ogr_api.h File Reference

#include "ogr_core.h"

Go to the source code of this file.

Functions

OGRErr OGR_G_CreateFromWkb (unsigned char *, OGRSpatialReferenceH, OGRGeometryH *, int)
 Create a geometry object of the appropriate type from it's well known binary representation.
OGRErr OGR_G_CreateFromWkt (char **, OGRSpatialReferenceH, OGRGeometryH *)
 Create a geometry object of the appropriate type from it's well known text representation.
void OGR_G_DestroyGeometry (OGRGeometryH)
 Destroy geometry object.
OGRGeometryH OGR_G_CreateGeometry (OGRwkbGeometryType)
 Create an empty geometry of desired type.
int OGR_G_GetDimension (OGRGeometryH)
 Get the dimension of this geometry.
int OGR_G_GetCoordinateDimension (OGRGeometryH)
 Get the dimension of the coordinates in this geometry.
OGRGeometryH OGR_G_Clone (OGRGeometryH)
 Make a copy of this object.
void OGR_G_GetEnvelope (OGRGeometryH, OGREnvelope *)
 Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure.
OGRErr OGR_G_ImportFromWkb (OGRGeometryH, unsigned char *, int)
 Assign geometry from well known binary data.
OGRErr OGR_G_ExportToWkb (OGRGeometryH, OGRwkbByteOrder, unsigned char *)
 Convert a geometry into well known binary format.
int OGR_G_WkbSize (OGRGeometryH hGeom)
 Returns size of related binary representation.
OGRErr OGR_G_ImportFromWkt (OGRGeometryH, char **)
 Assign geometry from well known text data.
OGRErr OGR_G_ExportToWkt (OGRGeometryH, char **)
 Convert a geometry into well known text format.
OGRwkbGeometryType OGR_G_GetGeometryType (OGRGeometryH)
 Fetch geometry type.
const char * OGR_G_GetGeometryName (OGRGeometryH)
 Fetch WKT name for geometry type.
void OGR_G_DumpReadable (OGRGeometryH, FILE *, const char *)
 Dump geometry in well known text format to indicated output file.
void OGR_G_FlattenTo2D (OGRGeometryH)
 Convert geometry to strictly 2D. In a sense this converts all Z coordinates to 0.0.
void OGR_G_AssignSpatialReference (OGRGeometryH, OGRSpatialReferenceH)
 Assign spatial reference to this object.
OGRSpatialReferenceH OGR_G_GetSpatialReference (OGRGeometryH)
 Returns spatial reference system for geometry.
OGRErr OGR_G_Transform (OGRGeometryH, OGRCoordinateTransformationH)
 Apply arbitrary coordinate transformation to geometry.
OGRErr OGR_G_TransformTo (OGRGeometryH, OGRSpatialReferenceH)
 Transform geometry to new spatial reference system.
void OGR_G_Segmentize (OGRGeometryH hGeom, double dfMaxLength)
 Modify the geometry such it has no segment longer then the given distance.
int OGR_G_Intersects (OGRGeometryH, OGRGeometryH)
 Do these features intersect?
int OGR_G_Equals (OGRGeometryH, OGRGeometryH)
 Returns TRUE if two geometries are equivalent.
int OGR_G_Disjoint (OGRGeometryH, OGRGeometryH)
 Test for disjointness.
int OGR_G_Touches (OGRGeometryH, OGRGeometryH)
 Test for touching.
int OGR_G_Crosses (OGRGeometryH, OGRGeometryH)
 Test for crossing.
int OGR_G_Within (OGRGeometryH, OGRGeometryH)
 Test for containment.
int OGR_G_Contains (OGRGeometryH, OGRGeometryH)
 Test for containment.
int OGR_G_Overlaps (OGRGeometryH, OGRGeometryH)
 Test for overlap.
OGRGeometryH OGR_G_GetBoundary (OGRGeometryH)
 Compute boundary.
OGRGeometryH OGR_G_ConvexHull (OGRGeometryH)
 Compute convex hull.
OGRGeometryH OGR_G_Buffer (OGRGeometryH, double, int)
 Compute buffer of geometry.
OGRGeometryH OGR_G_Intersection (OGRGeometryH, OGRGeometryH)
 Compute intersection.
OGRGeometryH OGR_G_Union (OGRGeometryH, OGRGeometryH)
 Compute union.
OGRGeometryH OGR_G_Difference (OGRGeometryH, OGRGeometryH)
 Compute difference.
OGRGeometryH OGR_G_SymmetricDifference (OGRGeometryH, OGRGeometryH)
 Compute symmetric difference.
double OGR_G_Distance (OGRGeometryH, OGRGeometryH)
 Compute distance between two geometries.
double OGR_G_GetArea (OGRGeometryH)
 Compute geometry area.
void OGR_G_Empty (OGRGeometryH)
 Clear geometry information. This restores the geometry to it's initial state after construction, and before assignment of actual geometry.
int OGR_G_IsEmpty (OGRGeometryH)
 Test if the geometry is empty.
int OGR_G_IsValid (OGRGeometryH)
 Test if the geometry is valid.
int OGR_G_IsSimple (OGRGeometryH)
 Returns TRUE if the geometry is simple.
int OGR_G_IsRing (OGRGeometryH)
 Test if the geometry is a ring.
int OGR_G_GetPointCount (OGRGeometryH)
 Fetch number of points from a geometry.
double OGR_G_GetX (OGRGeometryH, int)
 Fetch the x coordinate of a point from a geometry.
double OGR_G_GetY (OGRGeometryH, int)
 Fetch the x coordinate of a point from a geometry.
double OGR_G_GetZ (OGRGeometryH, int)
 Fetch the z coordinate of a point from a geometry.
void OGR_G_GetPoint (OGRGeometryH, int iPoint, double *, double *, double *)
 Fetch a point in line string or a point geometry.
void OGR_G_SetPoint (OGRGeometryH, int iPoint, double, double, double)
 Set the location of a vertex in a point or linestring geometry.
void OGR_G_SetPoint_2D (OGRGeometryH, int iPoint, double, double)
 Set the location of a vertex in a point or linestring geometry.
void OGR_G_AddPoint (OGRGeometryH, double, double, double)
 Add a point to a geometry (line string or point).
void OGR_G_AddPoint_2D (OGRGeometryH, double, double)
 Add a point to a geometry (line string or point).
int OGR_G_GetGeometryCount (OGRGeometryH)
 Fetch the number of elements in a geometry or number of geometries in container.
OGRGeometryH OGR_G_GetGeometryRef (OGRGeometryH, int)
 Fetch geometry from a geometry container.
OGRErr OGR_G_AddGeometry (OGRGeometryH, OGRGeometryH)
 Add a geometry to a geometry container.
OGRErr OGR_G_AddGeometryDirectly (OGRGeometryH, OGRGeometryH)
 Add a geometry directly to an existing geometry container.
OGRErr OGR_G_RemoveGeometry (OGRGeometryH, int, int)
 Remove a geometry from an exiting geometry container.
OGRGeometryH OGRBuildPolygonFromEdges (OGRGeometryH hLinesAsCollection, int bBestEffort, int bAutoClose, double dfTolerance, OGRErr *peErr)
OGRErr OGRSetGenerate_DB2_V72_BYTE_ORDER (int bGenerate_DB2_V72_BYTE_ORDER)
 Special entry point to enable the hack for generating DB2 V7.2 style WKB.
OGRFieldDefnH OGR_Fld_Create (const char *, OGRFieldType)
 Create a new field definition.
void OGR_Fld_Destroy (OGRFieldDefnH)
 Destroy a field definition.
void OGR_Fld_SetName (OGRFieldDefnH, const char *)
 Reset the name of this field.
const char * OGR_Fld_GetNameRef (OGRFieldDefnH)
 Fetch name of this field.
OGRFieldType OGR_Fld_GetType (OGRFieldDefnH)
 Fetch type of this field.
void OGR_Fld_SetType (OGRFieldDefnH, OGRFieldType)
 Set the type of this field. This should never be done to an OGRFieldDefn that is already part of an OGRFeatureDefn.
OGRJustification OGR_Fld_GetJustify (OGRFieldDefnH)
 Get the justification for this field.
void OGR_Fld_SetJustify (OGRFieldDefnH, OGRJustification)
 Set the justification for this field.
int OGR_Fld_GetWidth (OGRFieldDefnH)
 Get the formatting width for this field.
void OGR_Fld_SetWidth (OGRFieldDefnH, int)
 Set the formatting width for this field in characters.
int OGR_Fld_GetPrecision (OGRFieldDefnH)
 Get the formatting precision for this field. This should normally be zero for fields of types other than OFTReal.
void OGR_Fld_SetPrecision (OGRFieldDefnH, int)
 Set the formatting precision for this field in characters.
void OGR_Fld_Set (OGRFieldDefnH, const char *, OGRFieldType, int, int, OGRJustification)
 Set defining parameters for a field in one call.
const char * OGR_GetFieldTypeName (OGRFieldType)
 Fetch human readable name for a field type.
OGRFeatureDefnH OGR_FD_Create (const char *)
 Create a new feature definition object to hold the field definitions.
void OGR_FD_Destroy (OGRFeatureDefnH)
 Destroy a feature definition object and release all memory associated with it.
void OGR_FD_Release (OGRFeatureDefnH)
 Drop a reference, and destroy if unreferenced.
const char * OGR_FD_GetName (OGRFeatureDefnH)
 Get name of the OGRFeatureDefn passed as an argument.
int OGR_FD_GetFieldCount (OGRFeatureDefnH)
 Fetch number of fields on the passed feature definition.
OGRFieldDefnH OGR_FD_GetFieldDefn (OGRFeatureDefnH, int)
 Fetch field definition of the passed feature definition.
int OGR_FD_GetFieldIndex (OGRFeatureDefnH, const char *)
 Find field by name.
void OGR_FD_AddFieldDefn (OGRFeatureDefnH, OGRFieldDefnH)
 Add a new field definition to the passed feature definition.
OGRwkbGeometryType OGR_FD_GetGeomType (OGRFeatureDefnH)
 Fetch the geometry base type of the passed feature definition.
void OGR_FD_SetGeomType (OGRFeatureDefnH, OGRwkbGeometryType)
 Assign the base geometry type for the passed layer (the same as the feature definition).
int OGR_FD_Reference (OGRFeatureDefnH)
 Increments the reference count by one.
int OGR_FD_Dereference (OGRFeatureDefnH)
 Decrements the reference count by one.
int OGR_FD_GetReferenceCount (OGRFeatureDefnH)
 Fetch current reference count.
OGRFeatureH OGR_F_Create (OGRFeatureDefnH)
 Feature factory.
void OGR_F_Destroy (OGRFeatureH)
 Destroy feature.
OGRFeatureDefnH OGR_F_GetDefnRef (OGRFeatureH)
 Fetch feature definition.
OGRErr OGR_F_SetGeometryDirectly (OGRFeatureH, OGRGeometryH)
 Set feature geometry.
OGRErr OGR_F_SetGeometry (OGRFeatureH, OGRGeometryH)
 Set feature geometry.
OGRGeometryH OGR_F_GetGeometryRef (OGRFeatureH)
 Fetch an handle to feature geometry.
OGRFeatureH OGR_F_Clone (OGRFeatureH)
 Duplicate feature.
int OGR_F_Equal (OGRFeatureH, OGRFeatureH)
 Test if two features are the same.
int OGR_F_GetFieldCount (OGRFeatureH)
 Fetch number of fields on this feature This will always be the same as the field count for the OGRFeatureDefn.
OGRFieldDefnH OGR_F_GetFieldDefnRef (OGRFeatureH, int)
 Fetch definition for this field.
int OGR_F_GetFieldIndex (OGRFeatureH, const char *)
 Fetch the field index given field name.
int OGR_F_IsFieldSet (OGRFeatureH, int)
 Test if a field has ever been assigned a value or not.
void OGR_F_UnsetField (OGRFeatureH, int)
 Clear a field, marking it as unset.
OGRField * OGR_F_GetRawFieldRef (OGRFeatureH, int)
 Fetch an handle to the internal field value given the index.
int OGR_F_GetFieldAsInteger (OGRFeatureH, int)
 Fetch field value as integer.
double OGR_F_GetFieldAsDouble (OGRFeatureH, int)
 Fetch field value as a double.
const char * OGR_F_GetFieldAsString (OGRFeatureH, int)
 Fetch field value as a string.
const int * OGR_F_GetFieldAsIntegerList (OGRFeatureH, int, int *)
 Fetch field value as a list of integers.
const double * OGR_F_GetFieldAsDoubleList (OGRFeatureH, int, int *)
 Fetch field value as a list of doubles.
char ** OGR_F_GetFieldAsStringList (OGRFeatureH, int)
 Fetch field value as a list of strings.
GByte * OGR_F_GetFieldAsBinary (OGRFeatureH, int, int *)
 Fetch field value as binary.
int OGR_F_GetFieldAsDateTime (OGRFeatureH, int, int *, int *, int *, int *, int *, int *, int *)
 Fetch field value as date and time.
void OGR_F_SetFieldInteger (OGRFeatureH, int, int)
 Set field to integer value.
void OGR_F_SetFieldDouble (OGRFeatureH, int, double)
 Set field to double value.
void OGR_F_SetFieldString (OGRFeatureH, int, const char *)
 Set field to string value.
void OGR_F_SetFieldIntegerList (OGRFeatureH, int, int, int *)
 Set field to list of integers value.
void OGR_F_SetFieldDoubleList (OGRFeatureH, int, int, double *)
 Set field to list of doubles value.
void OGR_F_SetFieldStringList (OGRFeatureH, int, char **)
 Set field to list of strings value.
void OGR_F_SetFieldRaw (OGRFeatureH, int, OGRField *)
 Set field.
void OGR_F_SetFieldBinary (OGRFeatureH, int, int, GByte *)
 Set field to binary data.
void OGR_F_SetFieldDateTime (OGRFeatureH, int, int, int, int, int, int, int, int)
 Set field to datetime.
long OGR_F_GetFID (OGRFeatureH)
 Get feature identifier.
OGRErr OGR_F_SetFID (OGRFeatureH, long)
 Set the feature identifier.
void OGR_F_DumpReadable (OGRFeatureH, FILE *)
 Dump this feature in a human readable form.
OGRErr OGR_F_SetFrom (OGRFeatureH, OGRFeatureH, int)
 Set one feature from another.
OGRErr OGR_F_SetFromWithMap (OGRFeatureH, OGRFeatureH, int, int *)
 Set one feature from another.
const char * OGR_F_GetStyleString (OGRFeatureH)
 Fetch style string for this feature.
void OGR_F_SetStyleString (OGRFeatureH, const char *)
 Set feature style string. This method operate exactly as OGR_F_SetStyleStringDirectly() except that it does not assume ownership of the passed string, but instead makes a copy of it.
void OGR_F_SetStyleStringDirectly (OGRFeatureH, char *)
 Set feature style string. This method operate exactly as OGR_F_SetStyleString() except that it assumes ownership of the passed string.
OGRGeometryH OGR_L_GetSpatialFilter (OGRLayerH)
 This function returns the current spatial filter for this layer.
void OGR_L_SetSpatialFilter (OGRLayerH, OGRGeometryH)
 Set a new spatial filter.
void OGR_L_SetSpatialFilterRect (OGRLayerH, double, double, double, double)
 Set a new rectangular spatial filter.
OGRErr OGR_L_SetAttributeFilter (OGRLayerH, const char *)
 Set a new attribute query.
void OGR_L_ResetReading (OGRLayerH)
 Reset feature reading to start on the first feature.
OGRFeatureH OGR_L_GetNextFeature (OGRLayerH)
 Fetch the next available feature from this layer.
OGRErr OGR_L_SetNextByIndex (OGRLayerH, long)
 Move read cursor to the nIndex'th feature in the current resultset.
OGRFeatureH OGR_L_GetFeature (OGRLayerH, long)
 Fetch a feature by its identifier.
OGRErr OGR_L_SetFeature (OGRLayerH, OGRFeatureH)
 Rewrite an existing feature.
OGRErr OGR_L_CreateFeature (OGRLayerH, OGRFeatureH)
 Create and write a new feature within a layer.
OGRErr OGR_L_DeleteFeature (OGRLayerH, long)
 Delete feature from layer.
OGRFeatureDefnH OGR_L_GetLayerDefn (OGRLayerH)
 Fetch the schema information for this layer.
OGRSpatialReferenceH OGR_L_GetSpatialRef (OGRLayerH)
 Fetch the spatial reference system for this layer.
int OGR_L_GetFeatureCount (OGRLayerH, int)
 Fetch the feature count in this layer.
OGRErr OGR_L_GetExtent (OGRLayerH, OGREnvelope *, int)
 Fetch the extent of this layer.
int OGR_L_TestCapability (OGRLayerH, const char *)
 Test if this layer supported the named capability.
OGRErr OGR_L_CreateField (OGRLayerH, OGRFieldDefnH, int)
 Create a new field on a layer.
OGRErr OGR_L_StartTransaction (OGRLayerH)
 For datasources which support transactions, StartTransaction creates a transaction.
OGRErr OGR_L_CommitTransaction (OGRLayerH)
 For datasources which support transactions, CommitTransaction commits a transaction.
OGRErr OGR_L_RollbackTransaction (OGRLayerH)
 For datasources which support transactions, RollbackTransaction will roll back a datasource to its state before the start of the current transaction. If no transaction is active, or the rollback fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_NONE.
OGRErr OGR_L_SyncToDisk (OGRLayerH)
 Flush pending changes to disk.
const char * OGR_L_GetFIDColumn (OGRLayerH)
 This method returns the name of the underlying database column being used as the FID column, or "" if not supported.
const char * OGR_L_GetGeometryColumn (OGRLayerH)
 This method returns the name of the underlying database column being used as the geometry column, or "" if not supported.
void OGR_DS_Destroy (OGRDataSourceH)
 Closes opened datasource and releases allocated resources.
const char * OGR_DS_GetName (OGRDataSourceH)
 Returns the name of the data source.
int OGR_DS_GetLayerCount (OGRDataSourceH)
 Get the number of layers in this data source.
OGRLayerH OGR_DS_GetLayer (OGRDataSourceH, int)
 Fetch a layer by index.
OGRLayerH OGR_DS_GetLayerByName (OGRDataSourceH, const char *)
 Fetch a layer by name.
OGRErr OGR_DS_DeleteLayer (OGRDataSourceH, int)
 Delete the indicated layer from the datasource.
OGRSFDriverH OGR_DS_GetDriver (OGRDataSourceH)
 Returns the driver that the dataset was opened with.
OGRLayerH OGR_DS_CreateLayer (OGRDataSourceH, const char *, OGRSpatialReferenceH, OGRwkbGeometryType, char **)
 This function attempts to create a new layer on the data source with the indicated name, coordinate system, geometry type.
OGRLayerH OGR_DS_CopyLayer (OGRDataSourceH, OGRLayerH, const char *, char **)
 Duplicate an existing layer.
int OGR_DS_TestCapability (OGRDataSourceH, const char *)
 Test if capability is available.
OGRLayerH OGR_DS_ExecuteSQL (OGRDataSourceH, const char *, OGRGeometryH, const char *)
 Execute an SQL statement against the data store.
void OGR_DS_ReleaseResultSet (OGRDataSourceH, OGRLayerH)
 Release results of OGR_DS_ExecuteSQL().
OGRErr OGR_DS_SyncToDisk (OGRDataSourceH)
 Flush pending changes to disk.
const char * OGR_Dr_GetName (OGRSFDriverH)
 Fetch name of driver (file format). This name should be relatively short (10-40 characters), and should reflect the underlying file format. For instance "ESRI Shapefile".
OGRDataSourceH OGR_Dr_Open (OGRSFDriverH, const char *, int)
 Attempt to open file with this driver.
int OGR_Dr_TestCapability (OGRSFDriverH, const char *)
 Test if capability is available.
OGRDataSourceH OGR_Dr_CreateDataSource (OGRSFDriverH, const char *, char **)
 This function attempts to create a new data source based on the passed driver.
OGRDataSourceH OGR_Dr_CopyDataSource (OGRSFDriverH, OGRDataSourceH, const char *, char **)
 This function creates a new datasource by copying all the layers from the source datasource.
OGRErr OGR_Dr_DeleteDataSource (OGRSFDriverH, const char *)
 Delete a datasource.
OGRDataSourceH OGROpen (const char *, int, OGRSFDriverH *)
 Open a file / data source with one of the registered drivers.
OGRErr OGRReleaseDataSource (OGRDataSourceH)
 Drop a reference to this datasource, and if the reference count drops to zero close (destroy) the datasource.
void OGRRegisterDriver (OGRSFDriverH)
 Add a driver to the list of registered drivers.
int OGRGetDriverCount (void)
 Fetch the number of registered drivers.
OGRSFDriverH OGRGetDriver (int)
 Fetch the indicated driver.
OGRSFDriverH OGRGetDriverByName (const char *)
 Fetch the indicated driver.
int OGRGetOpenDSCount (void)
 Return the number of opened datasources.
OGRDataSourceH OGRGetOpenDS (int iDS)
 Return the iDS th datasource opened.
void OGRRegisterAll (void)
 Register all drivers.
void OGRCleanupAll (void)
 Cleanup all OGR related resources.
OGRStyleMgrH OGR_SM_Create (OGRStyleTableH hStyleTable)
 OGRStyleMgr factory.
void OGR_SM_Destroy (OGRStyleMgrH hSM)
 Destroy Style Manager.
const char * OGR_SM_InitFromFeature (OGRStyleMgrH hSM, OGRFeatureH hFeat)
 Initialize style manager from the style string of a feature.
int OGR_SM_InitStyleString (OGRStyleMgrH hSM, const char *pszStyleString)
 Initialize style manager from the style string.
int OGR_SM_GetPartCount (OGRStyleMgrH hSM, const char *pszStyleString)
 Get the number of parts in a style.
OGRStyleToolH OGR_SM_GetPart (OGRStyleMgrH hSM, int nPartId, const char *pszStyleString)
 Fetch a part (style tool) from the current style.
int OGR_SM_AddPart (OGRStyleMgrH hSM, OGRStyleToolH hST)
 Add a part (style tool) to the current style.
int OGR_SM_AddStyle (OGRStyleMgrH hSM, const char *pszStyleName, const char *pszStyleString)
OGRStyleToolH OGR_ST_Create (OGRSTClassId eClassId)
 OGRStyleTool factory.
void OGR_ST_Destroy (OGRStyleToolH hST)
 Destroy Style Tool.
OGRSTClassId OGR_ST_GetType (OGRStyleToolH hST)
 Determine type of Style Tool.
OGRSTUnitId OGR_ST_GetUnit (OGRStyleToolH hST)
 Get Style Tool units.
void OGR_ST_SetUnit (OGRStyleToolH hST, OGRSTUnitId eUnit, double dfGroundPaperScale)
 Set Style Tool units.
const char * OGR_ST_GetParamStr (OGRStyleToolH hST, int eParam, int *bValueIsNull)
 Get Style Tool parameter value as string.
int OGR_ST_GetParamNum (OGRStyleToolH hST, int eParam, int *bValueIsNull)
 Get Style Tool parameter value as an integer.
double OGR_ST_GetParamDbl (OGRStyleToolH hST, int eParam, int *bValueIsNull)
 Get Style Tool parameter value as a double.
void OGR_ST_SetParamStr (OGRStyleToolH hST, int eParam, const char *pszValue)
 Set Style Tool parameter value from a string.
void OGR_ST_SetParamNum (OGRStyleToolH hST, int eParam, int nValue)
 Set Style Tool parameter value from an integer.
const char * OGR_ST_GetStyleString (OGRStyleToolH hST)
 Get the style string for this Style Tool.
int OGR_ST_GetRGBFromString (OGRStyleToolH hST, const char *pszColor, int *pnRed, int *pnGreen, int *pnBlue, int *pnAlpha)
 Return the r,g,b,a components of a color encoded in #RRGGBB[AA] format.
OGRStyleTableH OGR_STBL_Create (void)
 OGRStyleTable factory.
void OGR_STBL_Destroy (OGRStyleTableH hSTBL)
 Destroy Style Table.
int OGR_STBL_SaveStyleTable (OGRStyleTableH hStyleTable, const char *pszFilename)
 Save a style table to a file.
int OGR_STBL_LoadStyleTable (OGRStyleTableH hStyleTable, const char *pszFilename)
 Load a style table from a file.
const char * OGR_STBL_Find (OGRStyleTableH hStyleTable, const char *pszName)
 Get a style string by name.
void OGR_STBL_ResetStyleStringReading (OGRStyleTableH hStyleTable)
 Reset the next style pointer to 0.
const char * OGR_STBL_GetNextStyle (OGRStyleTableH hStyleTable)
 Get the next style string from the table.
const char * OGR_STBL_GetLastStyleName (OGRStyleTableH hStyleTable)

Detailed Description

C API and defines for OGRFeature, OGRGeometry, and OGRDataSource related classes.

See also: ogr_geometry.h, ogr_feature.h, ogrsf_frmts.h, ogr_featurestyle.h

Function Documentation

OGRDataSourceH OGR_Dr_CopyDataSource ( OGRSFDriverH  hDriver,
OGRDataSourceH  hSrcDS,
const char *  pszNewName,
char **  papszOptions 
)

This function creates a new datasource by copying all the layers from the source datasource.

It is important to call OGR_DS_Destroy() when the datasource is no longer used to ensure that all data has been properly flushed to disk.

This function is the same as the C++ method OGRSFDriver::CopyDataSource().

Parameters:
hDriver handle to the driver on which data source creation is based.
hSrcDS source datasource
pszNewName the name for the new data source.
papszOptions a StringList of name=value options. Options are driver specific, and driver information can be found at the following url: http://www.gdal.org/ogr/ogr_formats.html
Returns:
NULL is returned on failure, or a new OGRDataSource handle on success.

References OGR_Dr_CopyDataSource().

Referenced by OGR_Dr_CopyDataSource().

OGRDataSourceH OGR_Dr_CreateDataSource ( OGRSFDriverH  hDriver,
const char *  pszName,
char **  papszOptions 
)

This function attempts to create a new data source based on the passed driver.

The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation.

It is important to call OGR_DS_Destroy() when the datasource is no longer used to ensure that all data has been properly flushed to disk.

This function is the same as the C++ method OGRSFDriver::CreateDataSource().

Parameters:
hDriver handle to the driver on which data source creation is based.
pszName the name for the new data source.
papszOptions a StringList of name=value options. Options are driver specific, and driver information can be found at the following url: http://www.gdal.org/ogr/ogr_formats.html
Returns:
NULL is returned on failure, or a new OGRDataSource handle on success.

References OGRSFDriver::CreateDataSource(), OGRDataSource::GetDriver(), OGR_Dr_CreateDataSource(), and OGRDataSource::SetDriver().

Referenced by OGR_Dr_CreateDataSource().

OGRErr OGR_Dr_DeleteDataSource ( OGRSFDriverH  hDriver,
const char *  pszDataSource 
)

Delete a datasource.

Delete (from the disk, in the database, ...) the named datasource. Normally it would be safest if the datasource was not open at the time.

Whether this is a supported operation on this driver case be tested using TestCapability() on ODrCDeleteDataSource.

This method is the same as the C++ method OGRSFDriver::DeleteDataSource().

Parameters:
hDriver handle to the driver on which data source deletion is based.
pszDataSource the name of the datasource to delete.
Returns:
OGRERR_NONE on success, and OGRERR_UNSUPPORTED_OPERATION if this is not supported by this driver.

References OGR_Dr_DeleteDataSource().

Referenced by OGR_Dr_DeleteDataSource().

const char * OGR_Dr_GetName ( OGRSFDriverH  hDriver  ) 

Fetch name of driver (file format). This name should be relatively short (10-40 characters), and should reflect the underlying file format. For instance "ESRI Shapefile".

This function is the same as the C++ method OGRSFDriver::GetName().

Parameters:
hDriver handle to the the driver to get the name from.
Returns:
driver name. This is an internal string and should not be modified or freed.

References OGR_Dr_GetName().

Referenced by OGR_Dr_GetName().

OGRDataSourceH OGR_Dr_Open ( OGRSFDriverH  hDriver,
const char *  pszName,
int  bUpdate 
)

Attempt to open file with this driver.

This function is the same as the C++ method OGRSFDriver::Open().

Parameters:
hDriver handle to the driver that is used to open file.
pszName the name of the file, or data source to try and open.
bUpdate TRUE if update access is required, otherwise FALSE (the default).
Returns:
NULL on error or if the pass name is not supported by this driver, otherwise an handle to an OGRDataSource. This OGRDataSource should be closed by deleting the object when it is no longer needed.

References OGRDataSource::GetDriver(), OGR_Dr_Open(), and OGRDataSource::SetDriver().

Referenced by OGR_Dr_Open().

int OGR_Dr_TestCapability ( OGRSFDriverH  hDriver,
const char *  pszCap 
)

Test if capability is available.

One of the following data source capability names can be passed into this function, and a TRUE or FALSE value will be returned indicating whether or not the capability is available for this object.

  • ODrCCreateDataSource: True if this driver can support creating data sources.

  • ODrCDeleteDataSource: True if this driver supports deleting data sources.

The #define macro forms of the capability names should be used in preference to the strings themselves to avoid mispelling.

This function is the same as the C++ method OGRSFDriver::TestCapability().

Parameters:
hDriver handle to the driver to test the capability against.
pszCap the capability to test.
Returns:
TRUE if capability available otherwise FALSE.

References OGR_Dr_TestCapability().

Referenced by OGR_Dr_TestCapability().

OGRLayerH OGR_DS_CopyLayer ( OGRDataSourceH  hDS,
OGRLayerH  hSrcLayer,
const char *  pszNewName,
char **  papszOptions 
)

Duplicate an existing layer.

This function creates a new layer, duplicate the field definitions of the source layer and then duplicate each features of the source layer. The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation. The source layer may come from another dataset.

This function is the same as the C++ method OGRDataSource::CopyLayer

Parameters:
hDS handle to the data source where to create the new layer
hSrcLayer handle to the source layer.
pszNewName the name of the layer to create.
papszOptions a StringList of name=value options. Options are driver specific.
Returns:
an handle to the layer, or NULL if an error occurs.

References OGR_DS_CopyLayer().

Referenced by OGR_DS_CopyLayer().

OGRLayerH OGR_DS_CreateLayer ( OGRDataSourceH  hDS,
const char *  pszName,
OGRSpatialReferenceH  hSpatialRef,
OGRwkbGeometryType  eType,
char **  papszOptions 
)

This function attempts to create a new layer on the data source with the indicated name, coordinate system, geometry type.

The papszOptions argument can be used to control driver specific creation options. These options are normally documented in the format specific documentation.

This function is the same as the C++ method OGRDataSource::CreateLayer().

Parameters:
hDS The dataset handle.
pszName the name for the new layer. This should ideally not match any existing layer on the datasource.
hSpatialRef handle to the coordinate system to use for the new layer, or NULL if no coordinate system is available.
eType the geometry type for the layer. Use wkbUnknown if there are no constraints on the types geometry to be written.
papszOptions a StringList of name=value options. Options are driver specific, and driver information can be found at the following url: http://www.gdal.org/ogr/ogr_formats.html
Returns:
NULL is returned on failure, or a new OGRLayer handle on success.
Example:

#include "ogrsf_frmts.h" 
#include "cpl_string.h"

...

        OGRLayerH *hLayer;
        char     *papszOptions;

        if( OGR_DS_TestCapability( hDS, ODsCCreateLayer ) )
        {
            ...
        }

        papszOptions = CSLSetNameValue( papszOptions, "DIM", "2" );
        hLayer = OGR_DS_CreateLayer( hDS, "NewLayer", NULL, wkbUnknown,
                                     papszOptions );
        CSLDestroy( papszOptions );

        if( hLayer == NULL )
        {
            ...
        }

References OGR_DS_CreateLayer().

Referenced by OGR_DS_CreateLayer().

OGRErr OGR_DS_DeleteLayer ( OGRDataSourceH  hDS,
int  iLayer 
)

Delete the indicated layer from the datasource.

If this method is supported the ODsCDeleteLayer capability will test TRUE on the OGRDataSource.

This method is the same as the C++ method OGRDataSource::DeleteLayer().

Parameters:
hDS handle to the datasource
iLayer the index of the layer to delete.
Returns:
OGRERR_NONE on success, or OGRERR_UNSUPPORTED_OPERATION if deleting layers is not supported for this datasource.

References OGR_DS_DeleteLayer().

Referenced by OGR_DS_DeleteLayer().

void OGR_DS_Destroy ( OGRDataSourceH  hDataSource  ) 

Closes opened datasource and releases allocated resources.

This method is the same as the C++ method OGRDataSource::DestroyDataSource().

Parameters:
hDataSource handle to allocated datasource object.

References OGR_DS_Destroy().

Referenced by OGR_DS_Destroy().

OGRLayerH OGR_DS_ExecuteSQL ( OGRDataSourceH  hDS,
const char *  pszSQLCommand,
OGRGeometryH  hSpatialFilter,
const char *  pszDialect 
)

Execute an SQL statement against the data store.

The result of an SQL query is either NULL for statements that are in error, or that have no results set, or an OGRLayer handle representing a results set from the query. Note that this OGRLayer is in addition to the layers in the data store and must be destroyed with OGR_DS_ReleaseResultsSet() before the data source is closed (destroyed).

For more information on the SQL dialect supported internally by OGR review the OGR SQL document. Some drivers (ie. Oracle and PostGIS) pass the SQL directly through to the underlying RDBMS.

This function is the same as the C++ method OGRDataSource::ExecuteSQL();

Parameters:
hDS handle to the data source on which the SQL query is executed.
pszSQLCommand the SQL statement to execute.
hSpatialFilter handle to a geometry which represents a spatial filter.
pszDialect allows control of the statement dialect. By default it is assumed to be "generic" SQL, whatever that is.
Returns:
an handle to a OGRLayer containing the results of the query. Deallocate with OGR_DS_ReleaseResultsSet().

References OGR_DS_ExecuteSQL().

Referenced by OGR_DS_ExecuteSQL().

OGRSFDriverH OGR_DS_GetDriver ( OGRDataSourceH  hDS  ) 

Returns the driver that the dataset was opened with.

This method is the same as the C++ method OGRDataSource::GetDriver()

Parameters:
hDS handle to the datasource
Returns:
NULL if driver info is not available, or pointer to a driver owned by the OGRSFDriverManager.

References OGR_DS_GetDriver().

Referenced by OGR_DS_GetDriver().

OGRLayerH OGR_DS_GetLayer ( OGRDataSourceH  hDS,
int  iLayer 
)

Fetch a layer by index.

The returned layer remains owned by the OGRDataSource and should not be deleted by the application.

This function is the same as the C++ method OGRDataSource::GetLayer().

Parameters:
hDS handle to the data source from which to get the layer.
iLayer a layer number between 0 and OGR_DS_GetLayerCount()-1.
Returns:
an handle to the layer, or NULL if iLayer is out of range or an error occurs.

References OGR_DS_GetLayer().

Referenced by OGR_DS_GetLayer().

OGRLayerH OGR_DS_GetLayerByName ( OGRDataSourceH  hDS,
const char *  pszLayerName 
)

Fetch a layer by name.

The returned layer remains owned by the OGRDataSource and should not be deleted by the application.

This function is the same as the C++ method OGRDataSource::GetLayerByName().

Parameters:
hDS handle to the data source from which to get the layer.
pszLayerName Layer the layer name of the layer to fetch.
Returns:
an handle to the layer, or NULL if the layer is not found or an error occurs.

References OGR_DS_GetLayerByName().

Referenced by OGR_DS_GetLayerByName().

int OGR_DS_GetLayerCount ( OGRDataSourceH  hDS  ) 

Get the number of layers in this data source.

This function is the same as the C++ method OGRDataSource::GetLayerCount().

Parameters:
hDS handle to the data source from which to get the number of layers.
Returns:
layer count.

References OGR_DS_GetLayerCount().

Referenced by OGR_DS_GetLayerCount().

const char * OGR_DS_GetName ( OGRDataSourceH  hDS  ) 

Returns the name of the data source.

This string should be sufficient to open the data source if passed to the same OGRSFDriver that this data source was opened with, but it need not be exactly the same string that was used to open the data source. Normally this is a filename.

This function is the same as the C++ method OGRDataSource::GetName().

Parameters:
hDS handle to the data source to get the name from.
Returns:
pointer to an internal name string which should not be modified or freed by the caller.

References OGR_DS_GetName().

Referenced by OGR_DS_GetName().

void OGR_DS_ReleaseResultSet ( OGRDataSourceH  hDS,
OGRLayerH  hLayer 
)

Release results of OGR_DS_ExecuteSQL().

This function should only be used to deallocate OGRLayers resulting from an OGR_DS_ExecuteSQL() call on the same OGRDataSource. Failure to deallocate a results set before destroying the OGRDataSource may cause errors.

This function is the same as the C++ method OGRDataSource::ReleaseResultsSet().

Parameters:
hDS an handle to the data source on which was executed an SQL query.
hLayer handle to the result of a previous OGR_DS_ExecuteSQL() call.

References OGR_DS_ReleaseResultSet().

Referenced by OGR_DS_ReleaseResultSet().

OGRErr OGR_DS_SyncToDisk ( OGRDataSourceH  hDS  ) 

Flush pending changes to disk.

This call is intended to force the datasource to flush any pending writes to disk, and leave the disk file in a consistent state. It would not normally have any effect on read-only datasources.

Some data sources do not implement this method, and will still return OGRERR_NONE. An error is only returned if an error occurs while attempting to flush to disk.

The default implementation of this method just calls the SyncToDisk() method on each of the layers. Conceptionally, calling SyncToDisk() on a datasource should include any work that might be accomplished by calling SyncToDisk() on layers in that data source.

In any event, you should always close any opened datasource with OGR_DS_Destroy() that will ensure all data is correctly flushed.

This method is the same as the C++ method OGRDataSource::SyncToDisk()

Parameters:
hDS handle to the data source
Returns:
OGRERR_NONE if no error occurs (even if nothing is done) or an error code.

References OGR_DS_SyncToDisk().

Referenced by OGR_DS_SyncToDisk().

int OGR_DS_TestCapability ( OGRDataSourceH  hDS,
const char *  pszCapability 
)

Test if capability is available.

One of the following data source capability names can be passed into this function, and a TRUE or FALSE value will be returned indicating whether or not the capability is available for this object.

  • ODsCCreateLayer: True if this datasource can create new layers.

The #define macro forms of the capability names should be used in preference to the strings themselves to avoid mispelling.

This function is the same as the C++ method OGRDataSource::TestCapability().

Parameters:
hDS handle to the data source against which to test the capability.
pszCapability the capability to test.
Returns:
TRUE if capability available otherwise FALSE.

References OGR_DS_TestCapability().

Referenced by OGR_DS_TestCapability().

OGRFeatureH OGR_F_Clone ( OGRFeatureH  hFeat  ) 

Duplicate feature.

The newly created feature is owned by the caller, and will have it's own reference to the OGRFeatureDefn.

This function is the same as the C++ method OGRFeature::Clone().

Parameters:
hFeat handle to the feature to clone.
Returns:
an handle to the new feature, exactly matching this feature.

References OGR_F_Clone().

Referenced by OGR_F_Clone().

OGRFeatureH OGR_F_Create ( OGRFeatureDefnH  hDefn  ) 

Feature factory.

Note that the OGRFeature will increment the reference count of it's defining OGRFeatureDefn. Destruction of the OGRFeatureDefn before destruction of all OGRFeatures that depend on it is likely to result in a crash.

This function is the same as the C++ method OGRFeature::OGRFeature().

Parameters:
hDefn handle to the feature class (layer) definition to which the feature will adhere.
Returns:
an handle to the new feature object with null fields and no geometry.

References OGR_F_Create().

Referenced by OGR_F_Create().

void OGR_F_Destroy ( OGRFeatureH  hFeat  ) 

Destroy feature.

The feature is deleted, but within the context of the GDAL/OGR heap. This is necessary when higher level applications use GDAL/OGR from a DLL and they want to delete a feature created within the DLL. If the delete is done in the calling application the memory will be freed onto the application heap which is inappropriate.

This function is the same as the C++ method OGRFeature::DestroyFeature().

Parameters:
hFeat handle to the feature to destroy.

References OGR_F_Destroy().

Referenced by OGR_F_Destroy().

void OGR_F_DumpReadable ( OGRFeatureH  hFeat,
FILE *  fpOut 
)

Dump this feature in a human readable form.

This dumps the attributes, and geometry; however, it doesn't definition information (other than field types and names), nor does it report the geometry spatial reference system.

This function is the same as the C++ method OGRFeature::DumpReadable().

Parameters:
hFeat handle to the feature to dump.
fpOut the stream to write to, such as strout.

References OGR_F_DumpReadable().

Referenced by OGR_F_DumpReadable().

int OGR_F_Equal ( OGRFeatureH  hFeat,
OGRFeatureH  hOtherFeat 
)

Test if two features are the same.

Two features are considered equal if the share them (handle equality) same OGRFeatureDefn, have the same field values, and the same geometry (as tested by OGR_G_Equal()) as well as the same feature id.

This function is the same as the C++ method OGRFeature::Equal().

Parameters:
hFeat handle to one of the feature.
hOtherFeat handle to the other feature to test this one against.
Returns:
TRUE if they are equal, otherwise FALSE.

References OGR_F_Equal().

Referenced by OGR_F_Equal().

OGRFeatureDefnH OGR_F_GetDefnRef ( OGRFeatureH  hFeat  ) 

Fetch feature definition.

This function is the same as the C++ method OGRFeature::GetDefnRef().

Parameters:
hFeat handle to the feature to get the feature definition from.
Returns:
an handle to the feature definition object on which feature depends.

References OGR_F_GetDefnRef().

Referenced by OGR_F_GetDefnRef().

long OGR_F_GetFID ( OGRFeatureH  hFeat  ) 

Get feature identifier.

This function is the same as the C++ method OGRFeature::GetFID().

Parameters:
hFeat handle to the feature from which to get the feature identifier.
Returns:
feature id or OGRNullFID if none has been assigned.

References OGR_F_GetFID().

Referenced by OGR_F_GetFID().

GByte* OGR_F_GetFieldAsBinary ( OGRFeatureH  hFeat,
int  iField,
int *  pnBytes 
)

Fetch field value as binary.

Currently this method only works for OFTBinary fields.

This function is the same as the C++ method OGRFeature::GetFieldAsBinary().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnBytes location to place count of bytes returned.
Returns:
the field value. This list is internal, and should not be modified, or freed. It's lifetime may be very brief.

References OGR_F_GetFieldAsBinary().

Referenced by OGR_F_GetFieldAsBinary().

int OGR_F_GetFieldAsDateTime ( OGRFeatureH  hFeat,
int  iField,
int *  pnYear,
int *  pnMonth,
int *  pnDay,
int *  pnHour,
int *  pnMinute,
int *  pnSecond,
int *  pnTZFlag 
)

Fetch field value as date and time.

Currently this method only works for OFTDate, OFTTime and OFTDateTime fields.

This function is the same as the C++ method OGRFeature::GetFieldAsDateTime().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnYear (including century)
pnMonth (1-12)
pnDay (1-31)
pnHour (0-23)
pnMinute (0-59)
pnSecond (0-59)
pnTZFlag (0=unknown, 1=localtime, 100=GMT, see data model for details)
Returns:
TRUE on success or FALSE on failure.

References OGR_F_GetFieldAsDateTime().

Referenced by OGR_F_GetFieldAsDateTime().

double OGR_F_GetFieldAsDouble ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as a double.

OFTString features will be translated using atof(). OFTInteger fields will be cast to double. Other field types, or errors will result in a return value of zero.

This function is the same as the C++ method OGRFeature::GetFieldAsDouble().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value.

References OGR_F_GetFieldAsDouble().

Referenced by OGR_F_GetFieldAsDouble().

const double* OGR_F_GetFieldAsDoubleList ( OGRFeatureH  hFeat,
int  iField,
int *  pnCount 
)

Fetch field value as a list of doubles.

Currently this function only works for OFTRealList fields.

This function is the same as the C++ method OGRFeature::GetFieldAsDoubleList().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnCount an integer to put the list count (number of doubles) into.
Returns:
the field value. This list is internal, and should not be modified, or freed. It's lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.

References OGR_F_GetFieldAsDoubleList().

Referenced by OGR_F_GetFieldAsDoubleList().

int OGR_F_GetFieldAsInteger ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as integer.

OFTString features will be translated using atoi(). OFTReal fields will be cast to integer. Other field types, or errors will result in a return value of zero.

This function is the same as the C++ method OGRFeature::GetFieldAsInteger().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value.

References OGR_F_GetFieldAsInteger().

Referenced by OGR_F_GetFieldAsInteger().

const int* OGR_F_GetFieldAsIntegerList ( OGRFeatureH  hFeat,
int  iField,
int *  pnCount 
)

Fetch field value as a list of integers.

Currently this function only works for OFTIntegerList fields.

This function is the same as the C++ method OGRFeature::GetFieldAsIntegerList().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pnCount an integer to put the list count (number of integers) into.
Returns:
the field value. This list is internal, and should not be modified, or freed. It's lifetime may be very brief. If *pnCount is zero on return the returned pointer may be NULL or non-NULL.

References OGR_F_GetFieldAsIntegerList().

Referenced by OGR_F_GetFieldAsIntegerList().

const char* OGR_F_GetFieldAsString ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as a string.

OFTReal and OFTInteger fields will be translated to string using sprintf(), but not necessarily using the established formatting rules. Other field types, or errors will result in a return value of zero.

This function is the same as the C++ method OGRFeature::GetFieldAsString().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value. This string is internal, and should not be modified, or freed. It's lifetime may be very brief.

References OGR_F_GetFieldAsString().

Referenced by OGR_F_GetFieldAsString().

char** OGR_F_GetFieldAsStringList ( OGRFeatureH  hFeat,
int  iField 
)

Fetch field value as a list of strings.

Currently this method only works for OFTStringList fields.

The returned list is terminated by a NULL pointer. The number of elements can also be calculated using CSLCount().

This function is the same as the C++ method OGRFeature::GetFieldAsStringList().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the field value. This list is internal, and should not be modified, or freed. It's lifetime may be very brief.

References OGR_F_GetFieldAsStringList().

Referenced by OGR_F_GetFieldAsStringList().

int OGR_F_GetFieldCount ( OGRFeatureH  hFeat  ) 

Fetch number of fields on this feature This will always be the same as the field count for the OGRFeatureDefn.

This function is the same as the C++ method OGRFeature::GetFieldCount().

Parameters:
hFeat handle to the feature to get the fields count from.
Returns:
count of fields.

References OGR_F_GetFieldCount().

Referenced by OGR_F_GetFieldCount().

OGRFieldDefnH OGR_F_GetFieldDefnRef ( OGRFeatureH  hFeat,
int  i 
)

Fetch definition for this field.

This function is the same as the C++ method OGRFeature::GetFieldDefnRef().

Parameters:
hFeat handle to the feature on which the field is found.
i the field to fetch, from 0 to GetFieldCount()-1.
Returns:
an handle to the field definition (from the OGRFeatureDefn). This is an internal reference, and should not be deleted or modified.

References OGR_F_GetFieldDefnRef().

Referenced by OGR_F_GetFieldDefnRef().

int OGR_F_GetFieldIndex ( OGRFeatureH  hFeat,
const char *  pszName 
)

Fetch the field index given field name.

This is a cover for the OGRFeatureDefn::GetFieldIndex() method.

This function is the same as the C++ method OGRFeature::GetFieldIndex().

Parameters:
hFeat handle to the feature on which the field is found.
pszName the name of the field to search for.
Returns:
the field index, or -1 if no matching field is found.

References OGR_F_GetFieldIndex().

Referenced by OGR_F_GetFieldIndex().

OGRGeometryH OGR_F_GetGeometryRef ( OGRFeatureH  hFeat  ) 

Fetch an handle to feature geometry.

This function is the same as the C++ method OGRFeature::GetGeometryRef().

Parameters:
hFeat handle to the feature to get geometry from.
Returns:
an handle to internal feature geometry. This object should not be modified.

References OGR_F_GetGeometryRef().

Referenced by OGR_F_GetGeometryRef().

OGRField* OGR_F_GetRawFieldRef ( OGRFeatureH  hFeat,
int  iField 
)

Fetch an handle to the internal field value given the index.

This function is the same as the C++ method OGRFeature::GetRawFieldRef().

Parameters:
hFeat handle to the feature on which field is found.
iField the field to fetch, from 0 to GetFieldCount()-1.
Returns:
the returned handle is to an internal data structure, and should not be freed, or modified.

References OGR_F_GetRawFieldRef().

Referenced by OGR_F_GetRawFieldRef().

const char* OGR_F_GetStyleString ( OGRFeatureH  hFeat  ) 

Fetch style string for this feature.

Set the OGR Feature Style Specification for details on the format of this string, and ogr_featurestyle.h for services available to parse it.

This function is the same as the C++ method OGRFeature::GetStyleString().

Parameters:
hFeat handle to the feature to get the style from.
Returns:
a reference to a representation in string format, or NULL if there isn't one.

References OGR_F_GetStyleString().

Referenced by OGR_F_GetStyleString().

int OGR_F_IsFieldSet ( OGRFeatureH  hFeat,
int  iField 
)

Test if a field has ever been assigned a value or not.

This function is the same as the C++ method OGRFeature::IsFieldSet().

Parameters:
hFeat handle to the feature on which the field is.
iField the field to test.
Returns:
TRUE if the field has been set, otherwise false.

References OGR_F_IsFieldSet().

Referenced by OGR_F_IsFieldSet().

OGRErr OGR_F_SetFID ( OGRFeatureH  hFeat,
long  nFID 
)

Set the feature identifier.

For specific types of features this operation may fail on illegal features ids. Generally it always succeeds. Feature ids should be greater than or equal to zero, with the exception of OGRNullFID (-1) indicating that the feature id is unknown.

This function is the same as the C++ method OGRFeature::SetFID().

Parameters:
hFeat handle to the feature to set the feature id to.
nFID the new feature identifier value to assign.
Returns:
On success OGRERR_NONE, or on failure some other value.

References OGR_F_SetFID().

Referenced by OGR_F_SetFID().

void OGR_F_SetFieldBinary ( OGRFeatureH  hFeat,
int  iField,
int  nBytes,
GByte *  pabyData 
)

Set field to binary data.

This function currently on has an effect of OFTBinary fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nBytes the number of bytes in pabyData array.
pabyData the data to apply.

References OGR_F_SetFieldBinary().

Referenced by OGR_F_SetFieldBinary().

void OGR_F_SetFieldDateTime ( OGRFeatureH  hFeat,
int  iField,
int  nYear,
int  nMonth,
int  nDay,
int  nHour,
int  nMinute,
int  nSecond,
int  nTZFlag 
)

Set field to datetime.

This method currently only has an effect for OFTDate, OFTTime and OFTDateTime fields.

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nYear (including century)
nMonth (1-12)
nDay (1-31)
nHour (0-23)
nMinute (0-59)
nSecond (0-59)
nTZFlag (0=unknown, 1=localtime, 100=GMT, see data model for details)

References OGR_F_SetFieldDateTime().

Referenced by OGR_F_SetFieldDateTime().

void OGR_F_SetFieldDouble ( OGRFeatureH  hFeat,
int  iField,
double  dfValue 
)

Set field to double value.

OFTInteger and OFTReal fields will be set directly. OFTString fields will be assigned a string representation of the value, but not necessarily taking into account formatting constraints on this field. Other field types may be unaffected.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
dfValue the value to assign.

References OGR_F_SetFieldDouble().

Referenced by OGR_F_SetFieldDouble().

void OGR_F_SetFieldDoubleList ( OGRFeatureH  hFeat,
int  iField,
int  nCount,
double *  padfValues 
)

Set field to list of doubles value.

This function currently on has an effect of OFTRealList fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nCount the number of values in the list being assigned.
padfValues the values to assign.

References OGR_F_SetFieldDoubleList().

Referenced by OGR_F_SetFieldDoubleList().

void OGR_F_SetFieldInteger ( OGRFeatureH  hFeat,
int  iField,
int  nValue 
)

Set field to integer value.

OFTInteger and OFTReal fields will be set directly. OFTString fields will be assigned a string representation of the value, but not necessarily taking into account formatting constraints on this field. Other field types may be unaffected.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
nValue the value to assign.

References OGR_F_SetFieldInteger().

Referenced by OGR_F_SetFieldInteger().

void OGR_F_SetFieldIntegerList ( OGRFeatureH  hFeat,
int  iField,
int  nCount,
int *  panValues 
)

Set field to list of integers value.

This function currently on has an effect of OFTIntegerList fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
nCount the number of values in the list being assigned.
panValues the values to assign.

References OGR_F_SetFieldIntegerList().

Referenced by OGR_F_SetFieldIntegerList().

void OGR_F_SetFieldRaw ( OGRFeatureH  hFeat,
int  iField,
OGRField *  psValue 
)

Set field.

The passed value OGRField must be of exactly the same type as the target field, or an application crash may occur. The passed value is copied, and will not be affected. It remains the responsibility of the caller.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
psValue handle on the value to assign.

References OGR_F_SetFieldRaw().

Referenced by OGR_F_SetFieldRaw().

void OGR_F_SetFieldString ( OGRFeatureH  hFeat,
int  iField,
const char *  pszValue 
)

Set field to string value.

OFTInteger fields will be set based on an atoi() conversion of the string. OFTReal fields will be set based on an atof() conversion of the string. Other field types may be unaffected.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to fetch, from 0 to GetFieldCount()-1.
pszValue the value to assign.

References OGR_F_SetFieldString().

Referenced by OGR_F_SetFieldString().

void OGR_F_SetFieldStringList ( OGRFeatureH  hFeat,
int  iField,
char **  papszValues 
)

Set field to list of strings value.

This function currently on has an effect of OFTStringList fields.

This function is the same as the C++ method OGRFeature::SetField().

Parameters:
hFeat handle to the feature that owned the field.
iField the field to set, from 0 to GetFieldCount()-1.
papszValues the values to assign.

References OGR_F_SetFieldStringList().

Referenced by OGR_F_SetFieldStringList().

OGRErr OGR_F_SetFrom ( OGRFeatureH  hFeat,
OGRFeatureH  hOtherFeat,
int  bForgiving 
)

Set one feature from another.

Overwrite the contents of this feature from the geometry and attributes of another. The hOtherFeature does not need to have the same OGRFeatureDefn. Field values are copied by corresponding field names. Field types do not have to exactly match. OGR_F_SetField*() function conversion rules will be applied as needed.

This function is the same as the C++ method OGRFeature::SetFrom().

Parameters:
hFeat handle to the feature to set to.
hOtherFeat handle to the feature from which geometry, and field values will be copied.
bForgiving TRUE if the operation should continue despite lacking output fields matching some of the source fields.
Returns:
OGRERR_NONE if the operation succeeds, even if some values are not transferred, otherwise an error code.

References OGR_F_SetFrom().

Referenced by OGR_F_SetFrom().

OGRErr OGR_F_SetFromWithMap ( OGRFeatureH  hFeat,
OGRFeatureH  hOtherFeat,
int  bForgiving,
int *  panMap 
)

Set one feature from another.

Overwrite the contents of this feature from the geometry and attributes of another. The hOtherFeature does not need to have the same OGRFeatureDefn. Field values are copied according to the provided indices map. Field types do not have to exactly match. OGR_F_SetField*() function conversion rules will be applied as needed. This is more efficient than OGR_F_SetFrom() in that this doesn't lookup the fields by their names. Particularly useful when the field names don't match.

This function is the same as the C++ method OGRFeature::SetFrom().

Parameters:
hFeat handle to the feature to set to.
hOtherFeat handle to the feature from which geometry, and field values will be copied.
panMap Array of the indices of the destination feature's fields stored at the corresponding index of the source feature's fields. A value of -1 should be used to ignore the source's field. The array should not be NULL and be as long as the number of fields in the source feature.
bForgiving TRUE if the operation should continue despite lacking output fields matching some of the source fields.
Returns:
OGRERR_NONE if the operation succeeds, even if some values are not transferred, otherwise an error code.

References OGR_F_SetFromWithMap().

Referenced by OGR_F_SetFromWithMap().

OGRErr OGR_F_SetGeometry ( OGRFeatureH  hFeat,
OGRGeometryH  hGeom 
)

Set feature geometry.

This function updates the features geometry, and operate exactly as SetGeometryDirectly(), except that this function does not assume ownership of the passed geometry, but instead makes a copy of it.

This function is the same as the C++ OGRFeature::SetGeometry().

Parameters:
hFeat handle to the feature on which new geometry is applied to.
hGeom handle to the new geometry to apply to feature.
Returns:
OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).

References OGR_F_SetGeometry().

Referenced by OGR_F_SetGeometry().

OGRErr OGR_F_SetGeometryDirectly ( OGRFeatureH  hFeat,
OGRGeometryH  hGeom 
)

Set feature geometry.

This function updates the features geometry, and operate exactly as SetGeometry(), except that this function assumes ownership of the passed geometry.

This function is the same as the C++ method OGRFeature::SetGeometryDirectly.

Parameters:
hFeat handle to the feature on which to apply the geometry.
hGeom handle to the new geometry to apply to feature.
Returns:
OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the OGRFeatureDefn (checking not yet implemented).

References OGR_F_SetGeometryDirectly().

Referenced by OGR_F_SetGeometryDirectly().

void OGR_F_SetStyleString ( OGRFeatureH  hFeat,
const char *  pszStyle 
)

Set feature style string. This method operate exactly as OGR_F_SetStyleStringDirectly() except that it does not assume ownership of the passed string, but instead makes a copy of it.

This function is the same as the C++ method OGRFeature::SetStyleString().

Parameters:
hFeat handle to the feature to set style to.
pszStyle the style string to apply to this feature, cannot be NULL.

References OGR_F_SetStyleString().

Referenced by OGR_F_SetStyleString().

void OGR_F_SetStyleStringDirectly ( OGRFeatureH  hFeat,
char *  pszStyle 
)

Set feature style string. This method operate exactly as OGR_F_SetStyleString() except that it assumes ownership of the passed string.

This function is the same as the C++ method OGRFeature::SetStyleStringDirectly().

Parameters:
hFeat handle to the feature to set style to.
pszStyle the style string to apply to this feature, cannot be NULL.

References OGR_F_SetStyleStringDirectly().

Referenced by OGR_F_SetStyleStringDirectly().

void OGR_F_UnsetField ( OGRFeatureH  hFeat,
int  iField 
)

Clear a field, marking it as unset.

This function is the same as the C++ method OGRFeature::UnsetField().

Parameters:
hFeat handle to the feature on which the field is.
iField the field to unset.

References OGR_F_UnsetField().

Referenced by OGR_F_UnsetField().

void OGR_FD_AddFieldDefn ( OGRFeatureDefnH  hDefn,
OGRFieldDefnH  hNewField 
)

Add a new field definition to the passed feature definition.

This function should only be called while there are no OGRFeature objects in existance based on this OGRFeatureDefn. The OGRFieldDefn passed in is copied, and remains the responsibility of the caller.

This function is the same as the C++ method OGRFeatureDefn::AddFieldDefn.

Parameters:
hDefn handle to the feature definition to add the field definition to.
hNewField handle to the new field definition.

References OGR_FD_AddFieldDefn().

Referenced by OGR_FD_AddFieldDefn().

OGRFeatureDefnH OGR_FD_Create ( const char *  pszName  ) 

Create a new feature definition object to hold the field definitions.

The OGRFeatureDefn maintains a reference count, but this starts at zero, and should normally be incremented by the owner.

This function is the same as the C++ method OGRFeatureDefn::OGRFeatureDefn().

Parameters:
pszName the name to be assigned to this layer/class. It does not need to be unique.
Returns:
handle to the newly created feature definition.

References OGR_FD_Create().

Referenced by OGR_FD_Create().

int OGR_FD_Dereference ( OGRFeatureDefnH  hDefn  ) 

Decrements the reference count by one.

This function is the same as the C++ method OGRFeatureDefn::Dereference().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
Returns:
the updated reference count.

References OGR_FD_Dereference().

Referenced by OGR_FD_Dereference().

void OGR_FD_Destroy ( OGRFeatureDefnH  hDefn  ) 

Destroy a feature definition object and release all memory associated with it.

This function is the same as the C++ method OGRFeatureDefn::~OGRFeatureDefn().

Parameters:
hDefn handle to the feature definition to be destroyed.

References OGR_FD_Destroy().

Referenced by OGR_FD_Destroy().

int OGR_FD_GetFieldCount ( OGRFeatureDefnH  hDefn  ) 

Fetch number of fields on the passed feature definition.

This function is the same as the C++ OGRFeatureDefn::GetFieldCount().

Parameters:
hDefn handle to the feature definition to get the fields count from.
Returns:
count of fields.

References OGR_FD_GetFieldCount().

Referenced by OGR_FD_GetFieldCount().

OGRFieldDefnH OGR_FD_GetFieldDefn ( OGRFeatureDefnH  hDefn,
int  iField 
)

Fetch field definition of the passed feature definition.

This function is the same as the C++ method OGRFeatureDefn::GetFieldDefn().

Starting with GDAL 1.7.0, this method will also issue an error if the index is not valid.

Parameters:
hDefn handle to the feature definition to get the field definition from.
iField the field to fetch, between 0 and GetFieldCount()-1.
Returns:
an handle to an internal field definition object or NULL if invalid index. This object should not be modified or freed by the application.

References OGR_FD_GetFieldDefn().

Referenced by OGR_FD_GetFieldDefn().

int OGR_FD_GetFieldIndex ( OGRFeatureDefnH  hDefn,
const char *  pszFieldName 
)

Find field by name.

The field index of the first field matching the passed field name (case insensitively) is returned.

This function is the same as the C++ method OGRFeatureDefn::GetFieldIndex.

Parameters:
hDefn handle to the feature definition to get field index from.
pszFieldName the field name to search for.
Returns:
the field index, or -1 if no match found.

References OGR_FD_GetFieldIndex().

Referenced by OGR_FD_GetFieldIndex().

OGRwkbGeometryType OGR_FD_GetGeomType ( OGRFeatureDefnH  hDefn  ) 

Fetch the geometry base type of the passed feature definition.

This function is the same as the C++ method OGRFeatureDefn::GetGeomType().

Parameters:
hDefn handle to the feature definition to get the geometry type from.
Returns:
the base type for all geometry related to this definition.

References OGR_FD_GetGeomType().

Referenced by OGR_FD_GetGeomType().

const char* OGR_FD_GetName ( OGRFeatureDefnH  hDefn  ) 

Get name of the OGRFeatureDefn passed as an argument.

This function is the same as the C++ method OGRFeatureDefn::GetName().

Parameters:
hDefn handle to the feature definition to get the name from.
Returns:
the name. This name is internal and should not be modified, or freed.

References OGR_FD_GetName().

Referenced by OGR_FD_GetName().

int OGR_FD_GetReferenceCount ( OGRFeatureDefnH  hDefn  ) 

Fetch current reference count.

This function is the same as the C++ method OGRFeatureDefn::GetReferenceCount().

Parameters:
hDefn hanlde to the feature definition on witch OGRFeature are based on.
Returns:
the current reference count.

References OGR_FD_GetReferenceCount().

Referenced by OGR_FD_GetReferenceCount().

int OGR_FD_Reference ( OGRFeatureDefnH  hDefn  ) 

Increments the reference count by one.

The reference count is used keep track of the number of OGRFeature objects referencing this definition.

This function is the same as the C++ method OGRFeatureDefn::Reference().

Parameters:
hDefn handle to the feature definition on witch OGRFeature are based on.
Returns:
the updated reference count.

References OGR_FD_Reference().

Referenced by OGR_FD_Reference().

void OGR_FD_Release ( OGRFeatureDefnH  hDefn  ) 

Drop a reference, and destroy if unreferenced.

This function is the same as the C++ method OGRFeatureDefn::Release().

Parameters:
hDefn handle to the feature definition to be released.

References OGR_FD_Release().

Referenced by OGR_FD_Release().

void OGR_FD_SetGeomType ( OGRFeatureDefnH  hDefn,
OGRwkbGeometryType  eType 
)

Assign the base geometry type for the passed layer (the same as the feature definition).

All geometry objects using this type must be of the defined type or a derived type. The default upon creation is wkbUnknown which allows for any geometry type. The geometry type should generally not be changed after any OGRFeatures have been created against this definition.

This function is the same as the C++ method OGRFeatureDefn::SetGeomType().

Parameters:
hDefn handle to the layer or feature definition to set the geometry type to.
eType the new type to assign.

References OGR_FD_SetGeomType().

Referenced by OGR_FD_SetGeomType().

OGRFieldDefnH OGR_Fld_Create ( const char *  pszName,
OGRFieldType  eType 
)

Create a new field definition.

This function is the same as the CPP method OGRFieldDefn::OGRFieldDefn().

Parameters:
pszName the name of the new field definition.
eType the type of the new field definition.
Returns:
handle to the new field definition.

References OGR_Fld_Create().

Referenced by OGR_Fld_Create().

void OGR_Fld_Destroy ( OGRFieldDefnH  hDefn  ) 

Destroy a field definition.

Parameters:
hDefn handle to the field definition to destroy.

References OGR_Fld_Destroy().

Referenced by OGR_Fld_Destroy().

OGRJustification OGR_Fld_GetJustify ( OGRFieldDefnH  hDefn  ) 

Get the justification for this field.

This function is the same as the CPP method OGRFieldDefn::GetJustify().

Parameters:
hDefn handle to the field definition to get justification from.
Returns:
the justification.

References OGR_Fld_GetJustify().

Referenced by OGR_Fld_GetJustify().

const char* OGR_Fld_GetNameRef ( OGRFieldDefnH  hDefn  ) 

Fetch name of this field.

This function is the same as the CPP method OGRFieldDefn::GetNameRef().

Parameters:
hDefn handle to the field definition.
Returns:
the name of the field definition.

References OGR_Fld_GetNameRef().

Referenced by OGR_Fld_GetNameRef().

int OGR_Fld_GetPrecision ( OGRFieldDefnH  hDefn  ) 

Get the formatting precision for this field. This should normally be zero for fields of types other than OFTReal.

This function is the same as the CPP method OGRFieldDefn::GetPrecision().

Parameters:
hDefn handle to the field definition to get precision from.
Returns:
the precision.

References OGR_Fld_GetPrecision().

Referenced by OGR_Fld_GetPrecision().

OGRFieldType OGR_Fld_GetType ( OGRFieldDefnH  hDefn  ) 

Fetch type of this field.

This function is the same as the CPP method OGRFieldDefn::GetType().

Parameters:
hDefn handle to the field definition to get type from.
Returns:
field type.

References OGR_Fld_GetType().

Referenced by OGR_Fld_GetType().

int OGR_Fld_GetWidth ( OGRFieldDefnH  hDefn  ) 

Get the formatting width for this field.

This function is the same as the CPP method OGRFieldDefn::GetWidth().

Parameters:
hDefn handle to the field definition to get width from.
Returns:
the width, zero means no specified width.

References OGR_Fld_GetWidth().

Referenced by OGR_Fld_GetWidth().

void OGR_Fld_Set ( OGRFieldDefnH  hDefn,
const char *  pszNameIn,
OGRFieldType  eTypeIn,
int  nWidthIn,
int  nPrecisionIn,
OGRJustification  eJustifyIn 
)

Set defining parameters for a field in one call.

This function is the same as the CPP method OGRFieldDefn::Set().

Parameters:
hDefn handle to the field definition to set to.
pszNameIn the new name to assign.
eTypeIn the new type (one of the OFT values like OFTInteger).
nWidthIn the preferred formatting width. Defaults to zero indicating undefined.
nPrecisionIn number of decimals places for formatting, defaults to zero indicating undefined.
eJustifyIn the formatting justification (OJLeft or OJRight), defaults to OJUndefined.

References OGR_Fld_Set().

Referenced by OGR_Fld_Set().

void OGR_Fld_SetJustify ( OGRFieldDefnH  hDefn,
OGRJustification  eJustify 
)

Set the justification for this field.

This function is the same as the CPP method OGRFieldDefn::SetJustify().

Parameters:
hDefn handle to the field definition to set justification to.
eJustify the new justification.

References OGR_Fld_SetJustify().

Referenced by OGR_Fld_SetJustify().

void OGR_Fld_SetName ( OGRFieldDefnH  hDefn,
const char *  pszName 
)

Reset the name of this field.

This function is the same as the CPP method OGRFieldDefn::SetName().

Parameters:
hDefn handle to the field definition to apply the new name to.
pszName the new name to apply.

References OGR_Fld_SetName().

Referenced by OGR_Fld_SetName().

void OGR_Fld_SetPrecision ( OGRFieldDefnH  hDefn,
int  nPrecision 
)

Set the formatting precision for this field in characters.

This should normally be zero for fields of types other than OFTReal.

This function is the same as the CPP method OGRFieldDefn::SetPrecision().

Parameters:
hDefn handle to the field definition to set precision to.
nPrecision the new precision.

References OGR_Fld_SetPrecision().

Referenced by OGR_Fld_SetPrecision().

void OGR_Fld_SetType ( OGRFieldDefnH  hDefn,
OGRFieldType  eType 
)

Set the type of this field. This should never be done to an OGRFieldDefn that is already part of an OGRFeatureDefn.

This function is the same as the CPP method OGRFieldDefn::SetType().

Parameters:
hDefn handle to the field definition to set type to.
eType the new field type.

References OGR_Fld_SetType().

Referenced by OGR_Fld_SetType().

void OGR_Fld_SetWidth ( OGRFieldDefnH  hDefn,
int  nNewWidth 
)

Set the formatting width for this field in characters.

This function is the same as the CPP method OGRFieldDefn::SetWidth().

Parameters:
hDefn handle to the field definition to set width to.
nNewWidth the new width.

References OGR_Fld_SetWidth().

Referenced by OGR_Fld_SetWidth().

OGRErr OGR_G_AddGeometry ( OGRGeometryH  hGeom,
OGRGeometryH  hNewSubGeom 
)

Add a geometry to a geometry container.

Some subclasses of OGRGeometryCollection restrict the types of geometry that can be added, and may return an error. The passed geometry is cloned to make an internal copy.

There is no SFCOM analog to this method.

This function is the same as the CPP method OGRGeometryCollection::addGeometry.

Parameters:
hGeom existing geometry container.
hNewSubGeom geometry to add to the container.
Returns:
OGRERR_NONE if successful, or OGRERR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the type of existing geometry.

References OGRLineString::getGeometryType(), wkbGeometryCollection, wkbLineString, wkbMultiLineString, wkbMultiPoint, wkbMultiPolygon, wkbPolygon, and OGRLinearRing::WkbSize().

OGRErr OGR_G_AddGeometryDirectly ( OGRGeometryH  hGeom,
OGRGeometryH  hNewSubGeom 
)

Add a geometry directly to an existing geometry container.

Some subclasses of OGRGeometryCollection restrict the types of geometry that can be added, and may return an error. Ownership of the passed geometry is taken by the container rather than cloning as addGeometry() does.

This function is the same as the CPP method OGRGeometryCollection::addGeometryDirectly.

There is no SFCOM analog to this method.

Parameters:
hGeom existing geometry.
hNewSubGeom geometry to add to the existing geometry.
Returns:
OGRERR_NONE if successful, or OGRERR_UNSUPPORTED_GEOMETRY_TYPE if the geometry type is illegal for the type of geometry container.

References OGRLineString::getGeometryType(), wkbGeometryCollection, wkbLineString, wkbMultiLineString, wkbMultiPoint, wkbMultiPolygon, wkbPolygon, and OGRLinearRing::WkbSize().

void OGR_G_AddPoint ( OGRGeometryH  hGeom,
double  dfX,
double  dfY,
double  dfZ 
)

Add a point to a geometry (line string or point).

The vertex count of the line string is increased by one, and assigned from the passed location value.

Parameters:
hGeom handle to the geometry to add a point to.
dfX x coordinate of point to add.
dfY y coordinate of point to add.
dfZ z coordinate of point to add.

References wkbLineString, and wkbPoint.

void OGR_G_AddPoint_2D ( OGRGeometryH  hGeom,
double  dfX,
double  dfY 
)

Add a point to a geometry (line string or point).

The vertex count of the line string is increased by one, and assigned from the passed location value.

Parameters:
hGeom handle to the geometry to add a point to.
dfX x coordinate of point to add.
dfY y coordinate of point to add.

References wkbLineString, and wkbPoint.

void OGR_G_AssignSpatialReference ( OGRGeometryH  hGeom,
OGRSpatialReferenceH  hSRS 
)

Assign spatial reference to this object.

Any existing spatial reference is replaced, but under no circumstances does this result in the object being reprojected. It is just changing the interpretation of the existing geometry. Note that assigning a spatial reference increments the reference count on the OGRSpatialReference, but does not copy it.

This is similar to the SFCOM IGeometry::put_SpatialReference() method.

This function is the same as the CPP method OGRGeometry::assignSpatialReference.

Parameters:
hGeom handle on the geometry to apply the new spatial reference system.
hSRS handle on the new spatial reference system to apply.

References OGR_G_AssignSpatialReference().

Referenced by OGR_G_AssignSpatialReference().

OGRGeometryH OGR_G_Buffer ( OGRGeometryH  hTarget,
double  dfDist,
int  nQuadSegs 
)

Compute buffer of geometry.

Builds a new geometry containing the buffer region around the geometry on which it is invoked. The buffer is a polygon containing the region within the buffer distance of the original geometry.

Some buffer sections are properly described as curves, but are converted to approximate polygons. The nQuadSegs parameter can be used to control how many segements should be used to define a 90 degree curve - a quadrant of a circle. A value of 30 is a reasonable default. Large values result in large numbers of vertices in the resulting buffer geometry while small numbers reduce the accuracy of the result.

This function is the same as the C++ method OGRGeometry::Buffer().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hTarget the geometry.
dfDist the buffer distance to be applied.
nQuadSegs the number of segments used to approximate a 90 degree (quadrant) of curvature.
Returns:
the newly created geometry, or NULL if an error occurs.

References OGR_G_Buffer().

Referenced by OGR_G_Buffer().

OGRGeometryH OGR_G_Clone ( OGRGeometryH  hGeom  ) 

Make a copy of this object.

This function relates to the SFCOM IGeometry::clone() method.

This function is the same as the CPP method OGRGeometry::clone().

Parameters:
hGeom handle on the geometry to clone from.
Returns:
an handle on the copy of the geometry with the spatial reference system as the original.

References OGR_G_Clone().

Referenced by OGR_G_Clone().

int OGR_G_Contains ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for containment.

Tests if this geometry contains the other geometry.

This function is the same as the C++ method OGRGeometry::Contains().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if hThis contains hOther geometry, otherwise FALSE.

References OGR_G_Contains().

Referenced by OGR_G_Contains().

OGRGeometryH OGR_G_ConvexHull ( OGRGeometryH  hTarget  ) 

Compute convex hull.

A new geometry object is created and returned containing the convex hull of the geometry on which the method is invoked.

This function is the same as the C++ method OGRGeometry::ConvexHull().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hTarget The Geometry to calculate the convex hull of.
Returns:
a handle to a newly allocated geometry now owned by the caller, or NULL on failure.

References OGR_G_ConvexHull().

Referenced by OGR_G_ConvexHull().

OGRErr OGR_G_CreateFromWkb ( unsigned char *  pabyData,
OGRSpatialReferenceH  hSRS,
OGRGeometryH *  phGeometry,
int  nBytes 
)

Create a geometry object of the appropriate type from it's well known binary representation.

Note that if nBytes is passed as zero, no checking can be done on whether the pabyData is sufficient. This can result in a crash if the input data is corrupt. This function returns no indication of the number of bytes from the data source actually used to represent the returned geometry object. Use OGR_G_WkbSize() on the returned geometry to establish the number of bytes it required in WKB format.

The OGRGeometryFactory::createFromWkb() CPP method is the same as this function.

Parameters:
pabyData pointer to the input BLOB data.
hSRS handle to the spatial reference to be assigned to the created geometry object. This may be NULL.
phGeometry the newly created geometry object will be assigned to the indicated handle on return. This will be NULL in case of failure.
nBytes the number of bytes of data available in pabyData, or -1 if it is not known, but assumed to be sufficient.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.

References OGRGeometryFactory::createFromWkb(), and OGR_G_CreateFromWkb().

Referenced by OGR_G_CreateFromWkb().

OGRErr OGR_G_CreateFromWkt ( char **  ppszData,
OGRSpatialReferenceH  hSRS,
OGRGeometryH *  phGeometry 
)

Create a geometry object of the appropriate type from it's well known text representation.

The OGRGeometryFactory::createFromWkt CPP method is the same as this function.

Parameters:
ppszData input zero terminated string containing well known text representation of the geometry to be created. The pointer is updated to point just beyond that last character consumed.
hSRS handle to the spatial reference to be assigned to the created geometry object. This may be NULL.
phGeometry the newly created geometry object will be assigned to the indicated handle on return. This will be NULL if the method fails.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.

References OGRGeometryFactory::createFromWkt(), and OGR_G_CreateFromWkt().

Referenced by OGR_G_CreateFromWkt().

OGRGeometryH OGR_G_CreateGeometry ( OGRwkbGeometryType  eGeometryType  ) 

Create an empty geometry of desired type.

This is equivelent to allocating the desired geometry with new, but the allocation is guaranteed to take place in the context of the GDAL/OGR heap.

This function is the same as the CPP method OGRGeometryFactory::createGeometry.

Parameters:
eGeometryType the type code of the geometry to be created.
Returns:
handle to the newly create geometry or NULL on failure.

References OGRGeometryFactory::createGeometry(), and OGR_G_CreateGeometry().

Referenced by OGR_G_CreateGeometry().

int OGR_G_Crosses ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for crossing.

Tests if this geometry and the other geometry are crossing.

This function is the same as the C++ method OGRGeometry::Crosses().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are crossing, otherwise FALSE.

References OGR_G_Crosses().

Referenced by OGR_G_Crosses().

void OGR_G_DestroyGeometry ( OGRGeometryH  hGeom  ) 

Destroy geometry object.

Equivalent to invoking delete on a geometry, but it guaranteed to take place within the context of the GDAL/OGR heap.

This function is the same as the CPP method OGRGeometryFactory::destroyGeometry.

Parameters:
hGeom handle to the geometry to delete.

References OGRGeometryFactory::destroyGeometry(), and OGR_G_DestroyGeometry().

Referenced by OGR_G_DestroyGeometry().

OGRGeometryH OGR_G_Difference ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute difference.

Generates a new geometry which is the region of this geometry with the region of the other geometry removed.

This function is the same as the C++ method OGRGeometry::Difference().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the difference or NULL if the difference is empty or an error occurs.

References OGR_G_Difference().

Referenced by OGR_G_Difference().

int OGR_G_Disjoint ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for disjointness.

Tests if this geometry and the other geometry are disjoint.

This function is the same as the C++ method OGRGeometry::Disjoint().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are disjoint, otherwise FALSE.

References OGR_G_Disjoint().

Referenced by OGR_G_Disjoint().

double OGR_G_Distance ( OGRGeometryH  hFirst,
OGRGeometryH  hOther 
)

Compute distance between two geometries.

Returns the shortest distance between the two geometries.

This function is the same as the C++ method OGRGeometry::Distance().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hFirst the first geometry to compare against.
hOther the other geometry to compare against.
Returns:
the distance between the geometries or -1 if an error occurs.

References OGR_G_Distance().

Referenced by OGR_G_Distance().

void OGR_G_DumpReadable ( OGRGeometryH  hGeom,
FILE *  fp,
const char *  pszPrefix 
)

Dump geometry in well known text format to indicated output file.

This method is the same as the CPP method OGRGeometry::dumpReadable.

Parameters:
hGeom handle on the geometry to dump.
fp the text file to write the geometry to.
pszPrefix the prefix to put on each line of output.

References OGR_G_DumpReadable().

Referenced by OGR_G_DumpReadable().

void OGR_G_Empty ( OGRGeometryH  hGeom  ) 

Clear geometry information. This restores the geometry to it's initial state after construction, and before assignment of actual geometry.

This function relates to the SFCOM IGeometry::Empty() method.

This function is the same as the CPP method OGRGeometry::empty().

Parameters:
hGeom handle on the geometry to empty.

References OGR_G_Empty().

Referenced by OGR_G_Empty().

int OGR_G_Equals ( OGRGeometryH  hGeom,
OGRGeometryH  hOther 
)

Returns TRUE if two geometries are equivalent.

This function is the same as the CPP method OGRGeometry::Equals() method.

Parameters:
hGeom handle on the first geometry.
hOther handle on the other geometry to test against.
Returns:
TRUE if equivalent or FALSE otherwise.

References OGR_G_Equals().

Referenced by OGR_G_Equals().

OGRErr OGR_G_ExportToWkb ( OGRGeometryH  hGeom,
OGRwkbByteOrder  eOrder,
unsigned char *  pabyDstBuffer 
)

Convert a geometry into well known binary format.

This function relates to the SFCOM IWks::ExportToWKB() method.

This function is the same as the CPP method OGRGeometry::exportToWkb().

Parameters:
hGeom handle on the geometry to convert to a well know binary data from.
eOrder One of wkbXDR or wkbNDR indicating MSB or LSB byte order respectively.
pabyDstBuffer a buffer into which the binary representation is written. This buffer must be at least OGR_G_WkbSize() byte in size.
Returns:
Currently OGRERR_NONE is always returned.

References OGR_G_ExportToWkb().

Referenced by OGR_G_ExportToWkb().

OGRErr OGR_G_ExportToWkt ( OGRGeometryH  hGeom,
char **  ppszSrcText 
)

Convert a geometry into well known text format.

This function relates to the SFCOM IWks::ExportToWKT() method.

This function is the same as the CPP method OGRGeometry::exportToWkt().

Parameters:
hGeom handle on the geometry to convert to a text format from.
ppszSrcText a text buffer is allocated by the program, and assigned to the passed pointer.
Returns:
Currently OGRERR_NONE is always returned.

References OGR_G_ExportToWkt().

Referenced by OGR_G_ExportToWkt().

void OGR_G_FlattenTo2D ( OGRGeometryH  hGeom  ) 

Convert geometry to strictly 2D. In a sense this converts all Z coordinates to 0.0.

This function is the same as the CPP method OGRGeometry::flattenTo2D().

Parameters:
hGeom handle on the geometry to convert.

References OGR_G_FlattenTo2D().

Referenced by OGR_G_FlattenTo2D().

double OGR_G_GetArea ( OGRGeometryH  hGeom  ) 

Compute geometry area.

Computes the area for an OGRLinearRing, OGRPolygon or OGRMultiPolygon. Undefined for all other geometry types (returns zero).

This function utilizes the C++ get_Area() methods such as OGRPolygon::get_Area().

Parameters:
hGeom the geometry to operate on.
Returns:
the area or 0.0 for unsupported geometry types.

References wkbGeometryCollection, wkbLinearRing, wkbLineString, wkbMultiPolygon, and wkbPolygon.

OGRGeometryH OGR_G_GetBoundary ( OGRGeometryH  hTarget  ) 

Compute boundary.

A new geometry object is created and returned containing the boundary of the geometry on which the method is invoked.

This function is the same as the C++ method OGR_G_GetBoundary().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hTarget The Geometry to calculate the boundary of.
Returns:
a handle to a newly allocated geometry now owned by the caller, or NULL on failure.

References OGR_G_GetBoundary().

Referenced by OGR_G_GetBoundary().

int OGR_G_GetCoordinateDimension ( OGRGeometryH  hGeom  ) 

Get the dimension of the coordinates in this geometry.

This function corresponds to the SFCOM IGeometry::GetDimension() method.

This function is the same as the CPP method OGRGeometry::getCoordinateDimension().

Parameters:
hGeom handle on the geometry to get the dimension of the coordinates from.
Returns:
in practice this always returns 2 indicating that coordinates are specified within a two dimensional space.

References OGR_G_GetCoordinateDimension().

Referenced by OGR_G_GetCoordinateDimension().

int OGR_G_GetDimension ( OGRGeometryH  hGeom  ) 

Get the dimension of this geometry.

This function corresponds to the SFCOM IGeometry::GetDimension() method. It indicates the dimension of the geometry, but does not indicate the dimension of the underlying space (as indicated by OGR_G_GetCoordinateDimension() function).

This function is the same as the CPP method OGRGeometry::getDimension().

Parameters:
hGeom handle on the geometry to get the dimension from.
Returns:
0 for points, 1 for lines and 2 for surfaces.

References OGR_G_GetDimension().

Referenced by OGR_G_GetDimension().

void OGR_G_GetEnvelope ( OGRGeometryH  hGeom,
OGREnvelope *  psEnvelope 
)

Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure.

This function is the same as the CPP method OGRGeometry::getEnvelope().

Parameters:
hGeom handle of the geometry to get envelope from.
psEnvelope the structure in which to place the results.

References OGR_G_GetEnvelope().

Referenced by OGR_G_GetEnvelope().

int OGR_G_GetGeometryCount ( OGRGeometryH  hGeom  ) 

Fetch the number of elements in a geometry or number of geometries in container.

Only geometries of type wkbPolygon[25D], wkbMultiPoint[25D], wkbMultiLineString[25D], wkbMultiPolygon[25D] or wkbGeometryCollection[25D] may return a valid value. Other geometry types will silently return 0.

Parameters:
hGeom single geometry or geometry container from which to get the number of elements.
Returns:
the number of elements.

References wkbGeometryCollection, wkbMultiLineString, wkbMultiPoint, wkbMultiPolygon, and wkbPolygon.

const char* OGR_G_GetGeometryName ( OGRGeometryH  hGeom  ) 

Fetch WKT name for geometry type.

There is no SFCOM analog to this function.

This function is the same as the CPP method OGRGeometry::getGeometryName().

Parameters:
hGeom handle on the geometry to get name from.
Returns:
name used for this geometry type in well known text format.

References OGR_G_GetGeometryName().

Referenced by OGR_G_GetGeometryName().

OGRGeometryH OGR_G_GetGeometryRef ( OGRGeometryH  hGeom,
int  iSubGeom 
)

Fetch geometry from a geometry container.

This function returns an handle to a geometry within the container. The returned geometry remains owned by the container, and should not be modified. The handle is only valid untill the next change to the geometry container. Use OGR_G_Clone() to make a copy.

This function relates to the SFCOM IGeometryCollection::get_Geometry() method.

This function is the same as the CPP method OGRGeometryCollection::getGeometryRef().

Parameters:
hGeom handle to the geometry container from which to get a geometry from.
iSubGeom the index of the geometry to fetch, between 0 and getNumGeometries() - 1.
Returns:
handle to the requested geometry.

References wkbGeometryCollection, wkbMultiLineString, wkbMultiPoint, wkbMultiPolygon, and wkbPolygon.

OGRwkbGeometryType OGR_G_GetGeometryType ( OGRGeometryH  hGeom  ) 

Fetch geometry type.

Note that the geometry type may include the 2.5D flag. To get a 2D flattened version of the geometry type apply the wkbFlatten() macro to the return result.

This function is the same as the CPP method OGRGeometry::getGeometryType().

Parameters:
hGeom handle on the geometry to get type from.
Returns:
the geometry type code.

References OGR_G_GetGeometryType(), and wkbUnknown.

Referenced by OGR_G_GetGeometryType().

void OGR_G_GetPoint ( OGRGeometryH  hGeom,
int  i,
double *  pdfX,
double *  pdfY,
double *  pdfZ 
)

Fetch a point in line string or a point geometry.

Parameters:
hGeom handle to the geometry from which to get the coordinates.
i the vertex to fetch, from 0 to getNumPoints()-1, zero for a point.
pdfX value of x coordinate.
pdfY value of y coordinate.
pdfZ value of z coordinate.

References wkbLineString, and wkbPoint.

int OGR_G_GetPointCount ( OGRGeometryH  hGeom  ) 

Fetch number of points from a geometry.

Only wkbPoint[25D] or wkbLineString[25D] may return a valid value. Other geometry types will silently return 0.

Parameters:
hGeom handle to the geometry from which to get the number of points.
Returns:
the number of points.

References OGRLineString::getNumPoints(), wkbLineString, and wkbPoint.

OGRSpatialReferenceH OGR_G_GetSpatialReference ( OGRGeometryH  hGeom  ) 

Returns spatial reference system for geometry.

This function relates to the SFCOM IGeometry::get_SpatialReference() method.

This function is the same as the CPP method OGRGeometry::getSpatialReference().

Parameters:
hGeom handle on the geometry to get spatial reference from.
Returns:
a reference to the spatial reference geometry.

References OGR_G_GetSpatialReference().

Referenced by OGR_G_GetSpatialReference().

double OGR_G_GetX ( OGRGeometryH  hGeom,
int  i 
)

Fetch the x coordinate of a point from a geometry.

Parameters:
hGeom handle to the geometry from which to get the x coordinate.
i point to get the x coordinate.
Returns:
the X coordinate of this point.

References wkbLineString, and wkbPoint.

double OGR_G_GetY ( OGRGeometryH  hGeom,
int  i 
)

Fetch the x coordinate of a point from a geometry.

Parameters:
hGeom handle to the geometry from which to get the y coordinate.
i point to get the Y coordinate.
Returns:
the Y coordinate of this point.

References wkbLineString, and wkbPoint.

double OGR_G_GetZ ( OGRGeometryH  hGeom,
int  i 
)

Fetch the z coordinate of a point from a geometry.

Parameters:
hGeom handle to the geometry from which to get the Z coordinate.
i point to get the Z coordinate.
Returns:
the Z coordinate of this point.

References wkbLineString, and wkbPoint.

OGRErr OGR_G_ImportFromWkb ( OGRGeometryH  hGeom,
unsigned char *  pabyData,
int  nSize 
)

Assign geometry from well known binary data.

The object must have already been instantiated as the correct derived type of geometry object to match the binaries type.

This function relates to the SFCOM IWks::ImportFromWKB() method.

This function is the same as the CPP method OGRGeometry::importFromWkb().

Parameters:
hGeom handle on the geometry to assign the well know binary data to.
pabyData the binary input data.
nSize the size of pabyData in bytes, or zero if not known.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.

References OGR_G_ImportFromWkb().

Referenced by OGR_G_ImportFromWkb().

OGRErr OGR_G_ImportFromWkt ( OGRGeometryH  hGeom,
char **  ppszSrcText 
)

Assign geometry from well known text data.

The object must have already been instantiated as the correct derived type of geometry object to match the text type.

This function relates to the SFCOM IWks::ImportFromWKT() method.

This function is the same as the CPP method OGRGeometry::importFromWkt().

Parameters:
hGeom handle on the geometry to assign well know text data to.
ppszSrcText pointer to a pointer to the source text. The pointer is updated to pointer after the consumed text.
Returns:
OGRERR_NONE if all goes well, otherwise any of OGRERR_NOT_ENOUGH_DATA, OGRERR_UNSUPPORTED_GEOMETRY_TYPE, or OGRERR_CORRUPT_DATA may be returned.

References OGR_G_ImportFromWkt().

Referenced by OGR_G_ImportFromWkt().

OGRGeometryH OGR_G_Intersection ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute intersection.

Generates a new geometry which is the region of intersection of the two geometries operated on. The OGR_G_Intersects() function can be used to test if two geometries intersect.

This function is the same as the C++ method OGRGeometry::Intersection().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the intersection or NULL if there is no intersection or an error occurs.

References OGR_G_Intersection().

Referenced by OGR_G_Intersection().

int OGR_G_Intersects ( OGRGeometryH  hGeom,
OGRGeometryH  hOtherGeom 
)

Do these features intersect?

Currently this is not implemented in a rigerous fashion, and generally just tests whether the envelopes of the two features intersect. Eventually this will be made rigerous.

This function is the same as the CPP method OGRGeometry::Intersects.

Parameters:
hGeom handle on the first geometry.
hOtherGeom handle on the other geometry to test against.
Returns:
TRUE if the geometries intersect, otherwise FALSE.

References OGR_G_Intersects().

Referenced by OGR_G_Intersects().

int OGR_G_IsEmpty ( OGRGeometryH  hGeom  ) 

Test if the geometry is empty.

This method is the same as the CPP method OGRGeometry::IsEmpty().

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if the geometry has no points, otherwise FALSE.

References OGR_G_IsEmpty().

Referenced by OGR_G_IsEmpty().

int OGR_G_IsRing ( OGRGeometryH  hGeom  ) 

Test if the geometry is a ring.

This function is the same as the C++ method OGRGeometry::IsRing().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always return FALSE.

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if the geometry has no points, otherwise FALSE.

References OGR_G_IsRing().

Referenced by OGR_G_IsRing().

int OGR_G_IsSimple ( OGRGeometryH  hGeom  ) 

Returns TRUE if the geometry is simple.

Returns TRUE if the geometry has no anomalous geometric points, such as self intersection or self tangency. The description of each instantiable geometric class will include the specific conditions that cause an instance of that class to be classified as not simple.

This function is the same as the c++ method OGRGeometry::IsSimple() method.

If OGR is built without the GEOS library, this function will always return FALSE.

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if object is simple, otherwise FALSE.

References OGR_G_IsSimple().

Referenced by OGR_G_IsSimple().

int OGR_G_IsValid ( OGRGeometryH  hGeom  ) 

Test if the geometry is valid.

This function is the same as the C++ method OGRGeometry::IsValid().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always return FALSE.

Parameters:
hGeom The Geometry to test.
Returns:
TRUE if the geometry has no points, otherwise FALSE.

References OGR_G_IsValid().

Referenced by OGR_G_IsValid().

int OGR_G_Overlaps ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for overlap.

Tests if this geometry and the other geometry overlap, that is their intersection has a non-zero area.

This function is the same as the C++ method OGRGeometry::Overlaps().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are overlapping, otherwise FALSE.

References OGR_G_Overlaps().

Referenced by OGR_G_Overlaps().

OGRErr OGR_G_RemoveGeometry ( OGRGeometryH  hGeom,
int  iGeom,
int  bDelete 
)

Remove a geometry from an exiting geometry container.

Removing a geometry will cause the geometry count to drop by one, and all "higher" geometries will shuffle down one in index.

There is no SFCOM analog to this method.

This function is the same as the CPP method OGRGeometryCollection::removeGeometry().

Parameters:
hGeom the existing geometry to delete from.
iGeom the index of the geometry to delete. A value of -1 is a special flag meaning that all geometries should be removed.
bDelete if TRUE the geometry will be destroyed, otherwise it will not. The default is TRUE as the existing geometry is considered to own the geometries in it.
Returns:
OGRERR_NONE if successful, or OGRERR_FAILURE if the index is out of range.

References wkbGeometryCollection, wkbMultiLineString, wkbMultiPoint, wkbMultiPolygon, and wkbPolygon.

void OGR_G_Segmentize ( OGRGeometryH  hGeom,
double  dfMaxLength 
)

Modify the geometry such it has no segment longer then the given distance.

Interpolated points will have Z and M values (if needed) set to 0. Distance computation is performed in 2d only

This function is the same as the CPP method OGRGeometry::segmentize().

Parameters:
hGeom handle on the geometry to segmentize
dfMaxLength the maximum distance between 2 points after segmentization

References OGR_G_Segmentize().

Referenced by OGR_G_Segmentize().

void OGR_G_SetPoint ( OGRGeometryH  hGeom,
int  i,
double  dfX,
double  dfY,
double  dfZ 
)

Set the location of a vertex in a point or linestring geometry.

If iPoint is larger than the number of existing points in the linestring, the point count will be increased to accomodate the request.

Parameters:
hGeom handle to the geometry to add a vertex to.
i the index of the vertex to assign (zero based) or zero for a point.
dfX input X coordinate to assign.
dfY input Y coordinate to assign.
dfZ input Z coordinate to assign (defaults to zero).

References wkbLineString, and wkbPoint.

void OGR_G_SetPoint_2D ( OGRGeometryH  hGeom,
int  i,
double  dfX,
double  dfY 
)

Set the location of a vertex in a point or linestring geometry.

If iPoint is larger than the number of existing points in the linestring, the point count will be increased to accomodate the request.

Parameters:
hGeom handle to the geometry to add a vertex to.
i the index of the vertex to assign (zero based) or zero for a point.
dfX input X coordinate to assign.
dfY input Y coordinate to assign.

References wkbLineString, and wkbPoint.

OGRGeometryH OGR_G_SymmetricDifference ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute symmetric difference.

Generates a new geometry which is the symmetric difference of this geometry and the other geometry.

This function is the same as the C++ method OGRGeometry::SymmetricDifference().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the symmetric difference or NULL if the difference is empty or an error occurs.

References OGR_G_SymmetricDifference().

Referenced by OGR_G_SymmetricDifference().

int OGR_G_Touches ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for touching.

Tests if this geometry and the other geometry are touching.

This function is the same as the C++ method OGRGeometry::Touches().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if they are touching, otherwise FALSE.

References OGR_G_Touches().

Referenced by OGR_G_Touches().

OGRErr OGR_G_Transform ( OGRGeometryH  hGeom,
OGRCoordinateTransformationH  hTransform 
)

Apply arbitrary coordinate transformation to geometry.

This function will transform the coordinates of a geometry from their current spatial reference system to a new target spatial reference system. Normally this means reprojecting the vectors, but it could include datum shifts, and changes of units.

Note that this function does not require that the geometry already have a spatial reference system. It will be assumed that they can be treated as having the source spatial reference system of the OGRCoordinateTransformation object, and the actual SRS of the geometry will be ignored. On successful completion the output OGRSpatialReference of the OGRCoordinateTransformation will be assigned to the geometry.

This function is the same as the CPP method OGRGeometry::transform.

Parameters:
hGeom handle on the geometry to apply the transform to.
hTransform handle on the transformation to apply.
Returns:
OGRERR_NONE on success or an error code.

References OGR_G_Transform().

Referenced by OGR_G_Transform().

OGRErr OGR_G_TransformTo ( OGRGeometryH  hGeom,
OGRSpatialReferenceH  hSRS 
)

Transform geometry to new spatial reference system.

This function will transform the coordinates of a geometry from their current spatial reference system to a new target spatial reference system. Normally this means reprojecting the vectors, but it could include datum shifts, and changes of units.

This function will only work if the geometry already has an assigned spatial reference system, and if it is transformable to the target coordinate system.

Because this function requires internal creation and initialization of an OGRCoordinateTransformation object it is significantly more expensive to use this function to transform many geometries than it is to create the OGRCoordinateTransformation in advance, and call transform() with that transformation. This function exists primarily for convenience when only transforming a single geometry.

This function is the same as the CPP method OGRGeometry::transformTo.

Parameters:
hGeom handle on the geometry to apply the transform to.
hSRS handle on the spatial reference system to apply.
Returns:
OGRERR_NONE on success, or an error code.

References OGR_G_TransformTo().

Referenced by OGR_G_TransformTo().

OGRGeometryH OGR_G_Union ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Compute union.

Generates a new geometry which is the region of union of the two geometries operated on.

This function is the same as the C++ method OGRGeometry::Union().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry.
hOther the other geometry.
Returns:
a new geometry representing the union or NULL if an error occurs.

References OGR_G_Union().

Referenced by OGR_G_Union().

int OGR_G_Within ( OGRGeometryH  hThis,
OGRGeometryH  hOther 
)

Test for containment.

Tests if this geometry is within the other geometry.

This function is the same as the C++ method OGRGeometry::Within().

This function is built on the GEOS library, check it for the definition of the geometry operation. If OGR is built without the GEOS library, this function will always fail, issuing a CPLE_NotSupported error.

Parameters:
hThis the geometry to compare.
hOther the other geometry to compare.
Returns:
TRUE if hThis is within hOther, otherwise FALSE.

References OGR_G_Within().

Referenced by OGR_G_Within().

int OGR_G_WkbSize ( OGRGeometryH  hGeom  ) 

Returns size of related binary representation.

This function returns the exact number of bytes required to hold the well known binary representation of this geometry object. Its computation may be slightly expensive for complex geometries.

This function relates to the SFCOM IWks::WkbSize() method.

This function is the same as the CPP method OGRGeometry::WkbSize().

Parameters:
hGeom handle on the geometry to get the binary size from.
Returns:
size of binary representation in bytes.

References OGR_G_WkbSize().

Referenced by OGR_G_WkbSize().

const char* OGR_GetFieldTypeName ( OGRFieldType  eType  ) 

Fetch human readable name for a field type.

This function is the same as the CPP method OGRFieldDefn::GetFieldTypeName().

Parameters:
eType the field type to get name for.
Returns:
the name.

References OGRFieldDefn::GetFieldTypeName(), and OGR_GetFieldTypeName().

Referenced by OGR_GetFieldTypeName().

OGRErr OGR_L_CommitTransaction ( OGRLayerH  hLayer  ) 

For datasources which support transactions, CommitTransaction commits a transaction.

If no transaction is active, or the commit fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_NONE.

This function is the same as the C++ method OGRLayer::CommitTransaction().

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE on success.

References OGR_L_CommitTransaction().

Referenced by OGR_L_CommitTransaction().

OGRErr OGR_L_CreateFeature ( OGRLayerH  hLayer,
OGRFeatureH  hFeat 
)

Create and write a new feature within a layer.

The passed feature is written to the layer as a new feature, rather than overwriting an existing one. If the feature has a feature id other than OGRNullFID, then the native implementation may use that as the feature id of the new feature, but not necessarily. Upon successful return the passed feature will have been updated with the new feature id.

This function is the same as the C++ method OGRLayer::CreateFeature().

Parameters:
hLayer handle to the layer to write the feature to.
hFeat the handle of the feature to write to disk.
Returns:
OGRERR_NONE on success.

References OGR_L_CreateFeature().

Referenced by OGR_L_CreateFeature().

OGRErr OGR_L_CreateField ( OGRLayerH  hLayer,
OGRFieldDefnH  hField,
int  bApproxOK 
)

Create a new field on a layer.

You must use this to create new fields on a real layer. Internally the OGRFeatureDefn for the layer will be updated to reflect the new field. Applications should never modify the OGRFeatureDefn used by a layer directly.

This function is the same as the C++ method OGRLayer::CreateField().

Parameters:
hLayer handle to the layer to write the field definition.
hField handle of the field definition to write to disk.
bApproxOK If TRUE, the field may be created in a slightly different form depending on the limitations of the format driver.
Returns:
OGRERR_NONE on success.

References OGR_L_CreateField().

Referenced by OGR_L_CreateField().

OGRErr OGR_L_DeleteFeature ( OGRLayerH  hLayer,
long  nFID 
)

Delete feature from layer.

The feature with the indicated feature id is deleted from the layer if supported by the driver. Most drivers do not support feature deletion, and will return OGRERR_UNSUPPORTED_OPERATION. The OGR_L_TestCapability() function may be called with OLCDeleteFeature to check if the driver supports feature deletion.

This method is the same as the C++ method OGRLayer::DeleteFeature().

Parameters:
hLayer handle to the layer
nFID the feature id to be deleted from the layer
Returns:
OGRERR_NONE on success.

References OGR_L_DeleteFeature().

Referenced by OGR_L_DeleteFeature().

OGRErr OGR_L_GetExtent ( OGRLayerH  hLayer,
OGREnvelope *  psExtent,
int  bForce 
)

Fetch the extent of this layer.

Returns the extent (MBR) of the data in the layer. If bForce is FALSE, and it would be expensive to establish the extent then OGRERR_FAILURE will be returned indicating that the extent isn't know. If bForce is TRUE then some implementations will actually scan the entire layer once to compute the MBR of all the features in the layer.

Depending on the drivers, the returned extent may or may not take the spatial filter into account. So it is safer to call OGR_L_GetExtent() without setting a spatial filter.

Layers without any geometry may return OGRERR_FAILURE just indicating that no meaningful extents could be collected.

This function is the same as the C++ method OGRLayer::GetExtent().

Parameters:
hLayer handle to the layer from which to get extent.
psExtent the structure in which the extent value will be returned.
bForce Flag indicating whether the extent should be computed even if it is expensive.
Returns:
OGRERR_NONE on success, OGRERR_FAILURE if extent not known.

References OGR_L_GetExtent().

Referenced by OGR_L_GetExtent().

OGRFeatureH OGR_L_GetFeature ( OGRLayerH  hLayer,
long  nFeatureId 
)

Fetch a feature by its identifier.

This function will attempt to read the identified feature. The nFID value cannot be OGRNullFID. Success or failure of this operation is unaffected by the spatial or attribute filters.

If this function returns a non-NULL feature, it is guaranteed that its feature id (OGR_F_GetFID()) will be the same as nFID.

Use OGR_L_TestCapability(OLCRandomRead) to establish if this layer supports efficient random access reading via OGR_L_GetFeature(); however, the call should always work if the feature exists as a fallback implementation just scans all the features in the layer looking for the desired feature.

Sequential reads are generally considered interrupted by a OGR_L_GetFeature() call.

The returned feature should be free with OGR_F_Destroy().

This function is the same as the C++ method OGRLayer::GetFeature( ).

Parameters:
hLayer handle to the layer that owned the feature.
nFeatureId the feature id of the feature to read.
Returns:
an handle to a feature now owned by the caller, or NULL on failure.

References OGR_L_GetFeature().

Referenced by OGR_L_GetFeature().

int OGR_L_GetFeatureCount ( OGRLayerH  hLayer,
int  bForce 
)

Fetch the feature count in this layer.

Returns the number of features in the layer. For dynamic databases the count may not be exact. If bForce is FALSE, and it would be expensive to establish the feature count a value of -1 may be returned indicating that the count isn't know. If bForce is TRUE some implementations will actually scan the entire layer once to count objects.

The returned count takes the spatial filter into account.

This function is the same as the CPP OGRLayer::GetFeatureCount().

Parameters:
hLayer handle to the layer that owned the features.
bForce Flag indicating whether the count should be computed even if it is expensive.
Returns:
feature count, -1 if count not known.

References OGR_L_GetFeatureCount().

Referenced by OGR_L_GetFeatureCount().

const char * OGR_L_GetFIDColumn ( OGRLayerH  hLayer  ) 

This method returns the name of the underlying database column being used as the FID column, or "" if not supported.

This method is the same as the C++ method OGRLayer::GetFIDColumn()

Parameters:
hLayer handle to the layer
Returns:
fid column name.

References OGR_L_GetFIDColumn().

Referenced by OGR_L_GetFIDColumn().

const char * OGR_L_GetGeometryColumn ( OGRLayerH  hLayer  ) 

This method returns the name of the underlying database column being used as the geometry column, or "" if not supported.

This method is the same as the C++ method OGRLayer::GetGeometryColumn()

Parameters:
hLayer handle to the layer
Returns:
geometry column name.

References OGR_L_GetGeometryColumn().

Referenced by OGR_L_GetGeometryColumn().

OGRFeatureDefnH OGR_L_GetLayerDefn ( OGRLayerH  hLayer  ) 

Fetch the schema information for this layer.

The returned handle to the OGRFeatureDefn is owned by the OGRLayer, and should not be modified or freed by the application. It encapsulates the attribute schema of the features of the layer.

This function is the same as the C++ method OGRLayer::GetLayerDefn().

Parameters:
hLayer handle to the layer to get the schema information.
Returns:
an handle to the feature definition.

References OGR_L_GetLayerDefn().

Referenced by OGR_L_GetLayerDefn().

OGRFeatureH OGR_L_GetNextFeature ( OGRLayerH  hLayer  ) 

Fetch the next available feature from this layer.

The returned feature becomes the responsiblity of the caller to delete with OGR_F_Destroy(). It is critical that all features associated with an OGRLayer (more specifically an OGRFeatureDefn) be deleted before that layer/datasource is deleted.

Only features matching the current spatial filter (set with SetSpatialFilter()) will be returned.

This function implements sequential access to the features of a layer. The OGR_L_ResetReading() function can be used to start at the beginning again. Random reading, writing and spatial filtering will be added to the OGRLayer in the future.

This function is the same as the C++ method OGRLayer::GetNextFeature().

Parameters:
hLayer handle to the layer from which feature are read.
Returns:
an handle to a feature, or NULL if no more features are available.

References OGR_L_GetNextFeature().

Referenced by OGR_L_GetNextFeature().

OGRGeometryH OGR_L_GetSpatialFilter ( OGRLayerH  hLayer  ) 

This function returns the current spatial filter for this layer.

The returned pointer is to an internally owned object, and should not be altered or deleted by the caller.

This function is the same as the C++ method OGRLayer::GetSpatialFilter().

Parameters:
hLayer handle to the layer to get the spatial filter from.
Returns:
an handle to the spatial filter geometry.

References OGR_L_GetSpatialFilter().

Referenced by OGR_L_GetSpatialFilter().

OGRSpatialReferenceH OGR_L_GetSpatialRef ( OGRLayerH  hLayer  ) 

Fetch the spatial reference system for this layer.

The returned object is owned by the OGRLayer and should not be modified or freed by the application.

This function is the same as the C++ method OGRLayer::GetSpatialRef().

Parameters:
hLayer handle to the layer to get the spatial reference from.
Returns:
spatial reference, or NULL if there isn't one.

References OGR_L_GetSpatialRef().

Referenced by OGR_L_GetSpatialRef().

void OGR_L_ResetReading ( OGRLayerH  hLayer  ) 

Reset feature reading to start on the first feature.

This affects GetNextFeature().

This function is the same as the C++ method OGRLayer::ResetReading().

Parameters:
hLayer handle to the layer on which features are read.

References OGR_L_ResetReading().

Referenced by OGR_L_ResetReading().

OGRErr OGR_L_RollbackTransaction ( OGRLayerH  hLayer  ) 

For datasources which support transactions, RollbackTransaction will roll back a datasource to its state before the start of the current transaction. If no transaction is active, or the rollback fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_NONE.

This function is the same as the C++ method OGRLayer::RollbackTransaction().

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE on success.

References OGR_L_RollbackTransaction().

Referenced by OGR_L_RollbackTransaction().

OGRErr OGR_L_SetAttributeFilter ( OGRLayerH  hLayer,
const char *  pszQuery 
)

Set a new attribute query.

This function sets the attribute query string to be used when fetching features via the OGR_L_GetNextFeature() function. Only features for which the query evaluates as true will be returned.

The query string should be in the format of an SQL WHERE clause. For instance "population > 1000000 and population < 5000000" where population is an attribute in the layer. The query format is a restricted form of SQL WHERE clause as defined "eq_format=restricted_where" about half way through this document:

http://ogdi.sourceforge.net/prop/6.2.CapabilitiesMetadata.html

Note that installing a query string will generally result in resetting the current reading position (ala OGR_L_ResetReading()).

This function is the same as the C++ method OGRLayer::SetAttributeFilter().

Parameters:
hLayer handle to the layer on which attribute query will be executed.
pszQuery query in restricted SQL WHERE format, or NULL to clear the current query.
Returns:
OGRERR_NONE if successfully installed, or an error code if the query expression is in error, or some other failure occurs.

References OGR_L_SetAttributeFilter().

Referenced by OGR_L_SetAttributeFilter().

OGRErr OGR_L_SetFeature ( OGRLayerH  hLayer,
OGRFeatureH  hFeat 
)

Rewrite an existing feature.

This function will write a feature to the layer, based on the feature id within the OGRFeature.

Use OGR_L_TestCapability(OLCRandomWrite) to establish if this layer supports random access writing via OGR_L_SetFeature().

This function is the same as the C++ method OGRLayer::SetFeature().

Parameters:
hLayer handle to the layer to write the feature.
hFeat the feature to write.
Returns:
OGRERR_NONE if the operation works, otherwise an appropriate error code.

References OGR_L_SetFeature().

Referenced by OGR_L_SetFeature().

OGRErr OGR_L_SetNextByIndex ( OGRLayerH  hLayer,
long  nIndex 
)

Move read cursor to the nIndex'th feature in the current resultset.

This method allows positioning of a layer such that the GetNextFeature() call will read the requested feature, where nIndex is an absolute index into the current result set. So, setting it to 3 would mean the next feature read with GetNextFeature() would have been the 4th feature to have been read if sequential reading took place from the beginning of the layer, including accounting for spatial and attribute filters.

Only in rare circumstances is SetNextByIndex() efficiently implemented. In all other cases the default implementation which calls ResetReading() and then calls GetNextFeature() nIndex times is used. To determine if fast seeking is available on the current layer use the TestCapability() method with a value of OLCFastSetNextByIndex.

This method is the same as the C++ method OGRLayer::SetNextByIndex()

Parameters:
hLayer handle to the layer
nIndex the index indicating how many steps into the result set to seek.
Returns:
OGRERR_NONE on success or an error code.

References OGR_L_SetNextByIndex().

Referenced by OGR_L_SetNextByIndex().

void OGR_L_SetSpatialFilter ( OGRLayerH  hLayer,
OGRGeometryH  hGeom 
)

Set a new spatial filter.

This function set the geometry to be used as a spatial filter when fetching features via the OGR_L_GetNextFeature() function. Only features that geometrically intersect the filter geometry will be returned.

Currently this test is may be inaccurately implemented, but it is guaranteed that all features who's envelope (as returned by OGR_G_GetEnvelope()) overlaps the envelope of the spatial filter will be returned. This can result in more shapes being returned that should strictly be the case.

This function makes an internal copy of the passed geometry. The passed geometry remains the responsibility of the caller, and may be safely destroyed.

For the time being the passed filter geometry should be in the same SRS as the layer (as returned by OGR_L_GetSpatialRef()). In the future this may be generalized.

This function is the same as the C++ method OGRLayer::SetSpatialFilter.

Parameters:
hLayer handle to the layer on which to set the spatial filter.
hGeom handle to the geometry to use as a filtering region. NULL may be passed indicating that the current spatial filter should be cleared, but no new one instituted.

References OGR_L_SetSpatialFilter().

Referenced by OGR_L_SetSpatialFilter().

void OGR_L_SetSpatialFilterRect ( OGRLayerH  hLayer,
double  dfMinX,
double  dfMinY,
double  dfMaxX,
double  dfMaxY 
)

Set a new rectangular spatial filter.

This method set rectangle to be used as a spatial filter when fetching features via the OGR_L_GetNextFeature() method. Only features that geometrically intersect the given rectangle will be returned.

The x/y values should be in the same coordinate system as the layer as a whole (as returned by OGRLayer::GetSpatialRef()). Internally this method is normally implemented as creating a 5 vertex closed rectangular polygon and passing it to OGRLayer::SetSpatialFilter(). It exists as a convenience.

The only way to clear a spatial filter set with this method is to call OGRLayer::SetSpatialFilter(NULL).

This method is the same as the C++ method OGRLayer::SetSpatialFilterRect().

Parameters:
hLayer handle to the layer on which to set the spatial filter.
dfMinX the minimum X coordinate for the rectangular region.
dfMinY the minimum Y coordinate for the rectangular region.
dfMaxX the maximum X coordinate for the rectangular region.
dfMaxY the maximum Y coordinate for the rectangular region.

References OGR_L_SetSpatialFilterRect().

Referenced by OGR_L_SetSpatialFilterRect().

OGRErr OGR_L_StartTransaction ( OGRLayerH  hLayer  ) 

For datasources which support transactions, StartTransaction creates a transaction.

If starting the transaction fails, will return OGRERR_FAILURE. Datasources which do not support transactions will always return OGRERR_NONE.

This function is the same as the C++ method OGRLayer::StartTransaction().

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE on success.

References OGR_L_StartTransaction().

Referenced by OGR_L_StartTransaction().

OGRErr OGR_L_SyncToDisk ( OGRLayerH  hLayer  ) 

Flush pending changes to disk.

This call is intended to force the layer to flush any pending writes to disk, and leave the disk file in a consistent state. It would not normally have any effect on read-only datasources.

Some layers do not implement this method, and will still return OGRERR_NONE. The default implementation just returns OGRERR_NONE. An error is only returned if an error occurs while attempting to flush to disk.

In any event, you should always close any opened datasource with OGR_DS_Destroy() that will ensure all data is correctly flushed.

This method is the same as the C++ method OGRLayer::SyncToDisk()

Parameters:
hLayer handle to the layer
Returns:
OGRERR_NONE if no error occurs (even if nothing is done) or an error code.

References OGR_L_SyncToDisk().

Referenced by OGR_L_SyncToDisk().

int OGR_L_TestCapability ( OGRLayerH  hLayer,
const char *  pszCap 
)

Test if this layer supported the named capability.

The capability codes that can be tested are represented as strings, but #defined constants exists to ensure correct spelling. Specific layer types may implement class specific capabilities, but this can't generally be discovered by the caller.

  • OLCRandomRead / "RandomRead": TRUE if the GetFeature() method is implemented in an optimized way for this layer, as opposed to the default implementation using ResetReading() and GetNextFeature() to find the requested feature id.

  • OLCSequentialWrite / "SequentialWrite": TRUE if the CreateFeature() method works for this layer. Note this means that this particular layer is writable. The same OGRLayer class may returned FALSE for other layer instances that are effectively read-only.

  • OLCRandomWrite / "RandomWrite": TRUE if the SetFeature() method is operational on this layer. Note this means that this particular layer is writable. The same OGRLayer class may returned FALSE for other layer instances that are effectively read-only.

  • OLCFastSpatialFilter / "FastSpatialFilter": TRUE if this layer implements spatial filtering efficiently. Layers that effectively read all features, and test them with the OGRFeature intersection methods should return FALSE. This can be used as a clue by the application whether it should build and maintain its own spatial index for features in this layer.

  • OLCFastFeatureCount / "FastFeatureCount": TRUE if this layer can return a feature count (via OGR_L_GetFeatureCount()) efficiently ... ie. without counting the features. In some cases this will return TRUE until a spatial filter is installed after which it will return FALSE.

  • OLCFastGetExtent / "FastGetExtent": TRUE if this layer can return its data extent (via OGR_L_GetExtent()) efficiently ... ie. without scanning all the features. In some cases this will return TRUE until a spatial filter is installed after which it will return FALSE.

  • OLCFastSetNextByIndex / "FastSetNextByIndex": TRUE if this layer can perform the SetNextByIndex() call efficiently, otherwise FALSE.

  • OLCCreateField / "CreateField": TRUE if this layer can create new fields on the current layer using CreateField(), otherwise FALSE.

  • OLCDeleteFeature / "DeleteFeature": TRUE if the DeleteFeature() method is supported on this layer, otherwise FALSE.

  • OLCStringsAsUTF8 / "StringsAsUTF8": TRUE if values of OFTString fields are assured to be in UTF-8 format. If FALSE the encoding of fields is uncertain, though it might still be UTF-8.

  • OLCTransactions / "Transactions": TRUE if the StartTransaction(), CommitTransaction() and RollbackTransaction() methods work in a meaningful way, otherwise FALSE.

This function is the same as the C++ method OGRLayer::TestCapability().

Parameters:
hLayer handle to the layer to get the capability from.
pszCap the name of the capability to test.
Returns:
TRUE if the layer has the requested capability, or FALSE otherwise. OGRLayers will return FALSE for any unrecognised capabilities.

References OGR_L_TestCapability().

Referenced by OGR_L_TestCapability().

int OGR_SM_AddPart ( OGRStyleMgrH  hSM,
OGRStyleToolH  hST 
)

Add a part (style tool) to the current style.

This function is the same as the C++ method OGRStyleMgr::AddPart().

Parameters:
hSM handle to the style manager.
hST the style tool defining the part to add.
Returns:
TRUE on success, FALSE on errors.

References OGR_SM_AddPart().

Referenced by OGR_SM_AddPart().

int OGR_SM_AddStyle ( OGRStyleMgrH  hSM,
const char *  pszStyleName,
const char *  pszStyleString 
)

Add a style to the current style table.

This function is the same as the C++ method OGRStyleMgr::AddStyle().

Parameters:
hSM handle to the style manager.
pszStyleName the name of the style to add.
pszStyleString the style string to use, or NULL to use the style stored in the manager.
Returns:
TRUE on success, FALSE on errors.

References OGR_SM_AddStyle().

Referenced by OGR_SM_AddStyle().

OGRStyleMgrH OGR_SM_Create ( OGRStyleTableH  hStyleTable  ) 

OGRStyleMgr factory.

This function is the same as the C++ method OGRStyleMgr::OGRStyleMgr().

Parameters:
hStyleTable pointer to OGRStyleTable or NULL if not working with a style table.
Returns:
an handle to the new style manager object.

References OGR_SM_Create().

Referenced by OGR_SM_Create().

void OGR_SM_Destroy ( OGRStyleMgrH  hSM  ) 

Destroy Style Manager.

This function is the same as the C++ method OGRStyleMgr::~OGRStyleMgr().

Parameters:
hSM handle to the style manager to destroy.

References OGR_SM_Destroy().

Referenced by OGR_SM_Destroy().

OGRStyleToolH OGR_SM_GetPart ( OGRStyleMgrH  hSM,
int  nPartId,
const char *  pszStyleString 
)

Fetch a part (style tool) from the current style.

This function is the same as the C++ method OGRStyleMgr::GetPart().

Parameters:
hSM handle to the style manager.
nPartId the part number (0-based index).
pszStyleString (optional) the style string on which to operate. If NULL then the current style string stored in the style manager is used.
Returns:
OGRStyleToolH of the requested part (style tools) or NULL on error.

References OGR_SM_GetPart().

Referenced by OGR_SM_GetPart().

int OGR_SM_GetPartCount ( OGRStyleMgrH  hSM,
const char *  pszStyleString 
)

Get the number of parts in a style.

This function is the same as the C++ method OGRStyleMgr::GetPartCount().

Parameters:
hSM handle to the style manager.
pszStyleString (optional) the style string on which to operate. If NULL then the current style string stored in the style manager is used.
Returns:
the number of parts (style tools) in the style.

References OGR_SM_GetPartCount().

Referenced by OGR_SM_GetPartCount().

const char* OGR_SM_InitFromFeature ( OGRStyleMgrH  hSM,
OGRFeatureH  hFeat 
)

Initialize style manager from the style string of a feature.

This function is the same as the C++ method OGRStyleMgr::InitFromFeature().

Parameters:
hSM handle to the style manager.
hFeat handle to the new feature from which to read the style.
Returns:
a reference to the style string read from the feature, or NULL in case of error.

References OGR_SM_InitFromFeature().

Referenced by OGR_SM_InitFromFeature().

int OGR_SM_InitStyleString ( OGRStyleMgrH  hSM,
const char *  pszStyleString 
)

Initialize style manager from the style string.

This function is the same as the C++ method OGRStyleMgr::InitStyleString().

Parameters:
hSM handle to the style manager.
pszStyleString the style string to use (can be NULL).
Returns:
TRUE on success, FALSE on errors.

References OGR_SM_InitStyleString().

Referenced by OGR_SM_InitStyleString().

OGRStyleToolH OGR_ST_Create ( OGRSTClassId  eClassId  ) 

OGRStyleTool factory.

This function is a constructor for OGRStyleTool derived classes.

Parameters:
eClassId subclass of style tool to create. One of OGRSTCPen (1), OGRSTCBrush (2), OGRSTCSymbol (3) or OGRSTCLabel (4).
Returns:
an handle to the new style tool object or NULL if the creation failed.

References OGR_ST_Create().

Referenced by OGR_ST_Create().

void OGR_ST_Destroy ( OGRStyleToolH  hST  ) 

Destroy Style Tool.

Parameters:
hST handle to the style tool to destroy.

References OGR_ST_Destroy().

Referenced by OGR_ST_Destroy().

double OGR_ST_GetParamDbl ( OGRStyleToolH  hST,
int  eParam,
int *  bValueIsNull 
)

Get Style Tool parameter value as a double.

Maps to the OGRStyleTool subclasses' GetParamDbl() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
bValueIsNull pointer to an integer that will be set to TRUE or FALSE to indicate whether the parameter value is NULL.
Returns:
the parameter value as double and sets bValueIsNull.

References OGR_ST_GetParamDbl().

Referenced by OGR_ST_GetParamDbl().

int OGR_ST_GetParamNum ( OGRStyleToolH  hST,
int  eParam,
int *  bValueIsNull 
)

Get Style Tool parameter value as an integer.

Maps to the OGRStyleTool subclasses' GetParamNum() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
bValueIsNull pointer to an integer that will be set to TRUE or FALSE to indicate whether the parameter value is NULL.
Returns:
the parameter value as integer and sets bValueIsNull.

References OGR_ST_GetParamNum().

Referenced by OGR_ST_GetParamNum().

const char* OGR_ST_GetParamStr ( OGRStyleToolH  hST,
int  eParam,
int *  bValueIsNull 
)

Get Style Tool parameter value as string.

Maps to the OGRStyleTool subclasses' GetParamStr() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
bValueIsNull pointer to an integer that will be set to TRUE or FALSE to indicate whether the parameter value is NULL.
Returns:
the parameter value as string and sets bValueIsNull.

References OGR_ST_GetParamStr().

Referenced by OGR_ST_GetParamStr().

int OGR_ST_GetRGBFromString ( OGRStyleToolH  hST,
const char *  pszColor,
int *  pnRed,
int *  pnGreen,
int *  pnBlue,
int *  pnAlpha 
)

Return the r,g,b,a components of a color encoded in #RRGGBB[AA] format.

Maps to OGRStyleTool::GetRGBFromString().

Parameters:
hST handle to the style tool.
pszColor the color to parse
pnRed pointer to an int in which the red value will be returned
pnGreen pointer to an int in which the green value will be returned
pnBlue pointer to an int in which the blue value will be returned
pnAlpha pointer to an int in which the (optional) alpha value will be returned
Returns:
TRUE if the color could be succesfully parsed, or FALSE in case of errors.

References OGR_ST_GetRGBFromString().

Referenced by OGR_ST_GetRGBFromString().

const char* OGR_ST_GetStyleString ( OGRStyleToolH  hST  ) 

Get the style string for this Style Tool.

Maps to the OGRStyleTool subclasses' GetStyleString() methods.

Parameters:
hST handle to the style tool.
Returns:
the style string for this style tool or "" if the hST is invalid.

References OGR_ST_GetStyleString().

Referenced by OGR_ST_GetStyleString().

OGRSTClassId OGR_ST_GetType ( OGRStyleToolH  hST  ) 

Determine type of Style Tool.

Parameters:
hST handle to the style tool.
Returns:
the style tool type, one of OGRSTCPen (1), OGRSTCBrush (2), OGRSTCSymbol (3) or OGRSTCLabel (4). Returns OGRSTCNone (0) if the OGRStyleToolH is invalid.

References OGR_ST_GetType().

Referenced by OGR_ST_GetType().

OGRSTUnitId OGR_ST_GetUnit ( OGRStyleToolH  hST  ) 

Get Style Tool units.

Parameters:
hST handle to the style tool.
Returns:
the style tool units.

References OGR_ST_GetUnit().

Referenced by OGR_ST_GetUnit().

void OGR_ST_SetParamNum ( OGRStyleToolH  hST,
int  eParam,
int  nValue 
)

Set Style Tool parameter value from an integer.

Maps to the OGRStyleTool subclasses' SetParamNum() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
nValue the new parameter value

References OGR_ST_SetParamNum().

Referenced by OGR_ST_SetParamNum().

void OGR_ST_SetParamStr ( OGRStyleToolH  hST,
int  eParam,
const char *  pszValue 
)

Set Style Tool parameter value from a string.

Maps to the OGRStyleTool subclasses' SetParamStr() methods.

Parameters:
hST handle to the style tool.
eParam the parameter id from the enumeration corresponding to the type of this style tool (one of the OGRSTPenParam, OGRSTBrushParam, OGRSTSymbolParam or OGRSTLabelParam enumerations)
pszValue the new parameter value

References OGR_ST_SetParamStr().

Referenced by OGR_ST_SetParamStr().

void OGR_ST_SetUnit ( OGRStyleToolH  hST,
OGRSTUnitId  eUnit,
double  dfGroundPaperScale 
)

Set Style Tool units.

This function is the same as OGRStyleTool::SetUnit()

Parameters:
hST handle to the style tool.
eUnit the new unit.
dfGroundPaperScale ground to paper scale factor.

References OGR_ST_SetUnit().

Referenced by OGR_ST_SetUnit().

OGRStyleTableH OGR_STBL_Create ( void   ) 

OGRStyleTable factory.

This function is the same as the C++ method OGRStyleTable::OGRStyleTable().

Returns:
an handle to the new style table object.

References OGR_STBL_Create().

Referenced by OGR_STBL_Create().

void OGR_STBL_Destroy ( OGRStyleTableH  hSTBL  ) 

Destroy Style Table.

Parameters:
hSTBL handle to the style table to destroy.

References OGR_STBL_Destroy().

Referenced by OGR_STBL_Destroy().

const char* OGR_STBL_Find ( OGRStyleTableH  hStyleTable,
const char *  pszName 
)

Get a style string by name.

This function is the same as the C++ method OGRStyleTable::Find().

Parameters:
hStyleTable handle to the style table.
pszName the name of the style string to find.
Returns:
the style string matching the name or NULL if not found or error.

References OGR_STBL_Find().

Referenced by OGR_STBL_Find().

const char* OGR_STBL_GetLastStyleName ( OGRStyleTableH  hStyleTable  ) 

Get the style name of the last style string fetched with OGR_STBL_GetNextStyle.

This function is the same as the C++ method OGRStyleTable::GetStyleName().

Parameters:
hStyleTable handle to the style table.
Returns:
the Name of the last style string or NULL on error.

References OGR_STBL_GetLastStyleName().

Referenced by OGR_STBL_GetLastStyleName().

const char* OGR_STBL_GetNextStyle ( OGRStyleTableH  hStyleTable  ) 

Get the next style string from the table.

This function is the same as the C++ method OGRStyleTable::GetNextStyle().

Parameters:
hStyleTable handle to the style table.
Returns:
the next style string or NULL on error.

References OGR_STBL_GetNextStyle().

Referenced by OGR_STBL_GetNextStyle().

int OGR_STBL_LoadStyleTable ( OGRStyleTableH  hStyleTable,
const char *  pszFilename 
)

Load a style table from a file.

This function is the same as the C++ method OGRStyleTable::LoadStyleTable().

Parameters:
hStyleTable handle to the style table.
pszFilename the name of the file to load from.
Returns:
TRUE on success, FALSE on error

References OGR_STBL_LoadStyleTable().

Referenced by OGR_STBL_LoadStyleTable().

void OGR_STBL_ResetStyleStringReading ( OGRStyleTableH  hStyleTable  ) 

Reset the next style pointer to 0.

This function is the same as the C++ method OGRStyleTable::ResetStyleStringReading().

Parameters:
hStyleTable handle to the style table.

References OGR_STBL_ResetStyleStringReading().

Referenced by OGR_STBL_ResetStyleStringReading().

int OGR_STBL_SaveStyleTable ( OGRStyleTableH  hStyleTable,
const char *  pszFilename 
)

Save a style table to a file.

This function is the same as the C++ method OGRStyleTable::SaveStyleTable().

Parameters:
hStyleTable handle to the style table.
pszFilename the name of the file to save to.
Returns:
TRUE on success, FALSE on error

References OGR_STBL_SaveStyleTable().

Referenced by OGR_STBL_SaveStyleTable().

OGRGeometryH OGRBuildPolygonFromEdges ( OGRGeometryH  hLines,
int  bBestEffort,
int  bAutoClose,
double  dfTolerance,
OGRErr *  peErr 
)

Build a ring from a bunch of arcs.

Parameters:
hLines handle to an OGRGeometryCollection (or OGRMultiLineString) containing the line string geometries to be built into rings.
bBestEffort not yet implemented???.
bAutoClose indicates if the ring should be close when first and last points of the ring are the same.
dfTolerance tolerance into which two arcs are considered close enough to be joined.
peErr OGRERR_NONE on success, or OGRERR_FAILURE on failure.
Returns:
an handle to the new geometry, a polygon.

References OGRLineString::addPoint(), OGRPolygon::addRingDirectly(), OGRGeometryCollection::getGeometryRef(), OGRGeometry::getGeometryType(), OGRGeometryCollection::getNumGeometries(), OGRPolygon::getNumInteriorRings(), OGRLineString::getNumPoints(), OGRLineString::getX(), OGRLineString::getY(), OGRLineString::getZ(), OGRBuildPolygonFromEdges(), wkbGeometryCollection, wkbLineString, and wkbMultiLineString.

Referenced by OGRBuildPolygonFromEdges().

void OGRCleanupAll ( void   ) 

Cleanup all OGR related resources.

This function will destroy the OGRSFDriverRegistrar along with all registered drivers, and then cleanup long lived OSR (OGRSpatialReference) and CPL resources. This may be called in an application when OGR services are no longer needed. It is not normally required, but by freeing all dynamically allocated memory it can make memory leak testing easier.

In addition to destroying the OGRDriverRegistrar, this function also calls:

  • OSRCleanup()
  • CPLFinderClean()
  • VSICleanupFileManager()
  • CPLFreeConfig()
  • CPLCleanupTLS()

References OGRCleanupAll(), and OSRCleanup().

Referenced by OGRCleanupAll().

OGRSFDriverH OGRGetDriver ( int  iDriver  ) 

Fetch the indicated driver.

This function is the same as the C++ method OGRSFDriverRegistrar::GetDriver().

Parameters:
iDriver the driver index, from 0 to GetDriverCount()-1.
Returns:
handle to the driver, or NULL if iDriver is out of range.

References OGRSFDriverRegistrar::GetDriver(), and OGRGetDriver().

Referenced by OGRGetDriver().

OGRSFDriverH OGRGetDriverByName ( const char *  pszName  ) 

Fetch the indicated driver.

This function is the same as the C++ method OGRSFDriverRegistrar::GetDriverByName()

Parameters:
pszName the driver name
Returns:
the driver, or NULL if no driver with that name is found

References OGRSFDriverRegistrar::GetDriverByName(), OGRSFDriverRegistrar::GetRegistrar(), and OGRGetDriverByName().

Referenced by OGRGetDriverByName().

int OGRGetDriverCount ( void   ) 

Fetch the number of registered drivers.

This function is the same as the C++ method OGRSFDriverRegistrar::GetDriverCount().

Returns:
the drivers count.

References OGRSFDriverRegistrar::GetDriverCount(), and OGRGetDriverCount().

Referenced by OGRGetDriverCount().

OGRDataSourceH OGRGetOpenDS ( int  iDS  ) 

Return the iDS th datasource opened.

This function is the same as the C++ method OGRSFDriverRegistrar::GetOpenDS.

Parameters:
iDS the index of the dataset to return (between 0 and GetOpenDSCount() - 1)

References OGRSFDriverRegistrar::GetOpenDS(), OGRSFDriverRegistrar::GetRegistrar(), and OGRGetOpenDS().

Referenced by OGRGetOpenDS().

int OGRGetOpenDSCount ( void   ) 

Return the number of opened datasources.

This function is the same as the C++ method OGRSFDriverRegistrar::GetOpenDSCount()

Returns:
the number of opened datasources.

References OGRSFDriverRegistrar::GetOpenDSCount(), OGRSFDriverRegistrar::GetRegistrar(), and OGRGetOpenDSCount().

Referenced by OGRGetOpenDSCount().

OGRDataSourceH OGROpen ( const char *  pszName,
int  bUpdate,
OGRSFDriverH *  pahDriverList 
)

Open a file / data source with one of the registered drivers.

This function loops through all the drivers registered with the driver manager trying each until one succeeds with the given data source. This function is static. Applications don't normally need to use any other OGRSFDriverRegistrar function, not do they normally need to have a pointer to an OGRSFDriverRegistrar instance.

If this function fails, CPLGetLastErrorMsg() can be used to check if there is an error message explaining why.

This function is the same as the C++ method OGRSFDriverRegistrar::Open().

Parameters:
pszName the name of the file, or data source to open.
bUpdate FALSE for read-only access (the default) or TRUE for read-write access.
pahDriverList if non-NULL, this argument will be updated with a pointer to the driver which was used to open the data source.
Returns:
NULL on error or if the pass name is not supported by this driver, otherwise an handle to an OGRDataSource. This OGRDataSource should be closed by deleting the object when it is no longer needed.
Example:

    OGRDataSourceH	hDS;
    OGRSFDriverH        *pahDriver;

    hDS = OGROpen( "polygon.shp", 0, pahDriver );
    if( hDS == NULL )
    {
        return;
    }

    ... use the data source ...

    OGRReleaseDataSource( hDS );

References OGROpen(), and OGRSFDriverRegistrar::Open().

Referenced by OGROpen().

void OGRRegisterDriver ( OGRSFDriverH  hDriver  ) 

Add a driver to the list of registered drivers.

If the passed driver is already registered (based on handle comparison) then the driver isn't registered. New drivers are added at the end of the list of registered drivers.

This function is the same as the C++ method OGRSFDriverRegistrar::RegisterDriver().

Parameters:
hDriver handle to the driver to add.

References OGRSFDriverRegistrar::GetRegistrar(), OGRRegisterDriver(), and OGRSFDriverRegistrar::RegisterDriver().

Referenced by OGRRegisterDriver().

OGRErr OGRReleaseDataSource ( OGRDataSourceH  hDS  ) 

Drop a reference to this datasource, and if the reference count drops to zero close (destroy) the datasource.

Internally this actually calls the OGRSFDriverRegistrar::ReleaseDataSource() method. This method is essentially a convenient alias.

This method is the same as the C++ method OGRDataSource::Release()

Parameters:
hDS handle to the data source to release
Returns:
OGRERR_NONE on success or an error code.

References OGRSFDriverRegistrar::GetRegistrar(), OGRReleaseDataSource(), and OGRSFDriverRegistrar::ReleaseDataSource().

Referenced by OGRReleaseDataSource().

OGRErr OGRSetGenerate_DB2_V72_BYTE_ORDER ( int  bGenerate_DB2_V72_BYTE_ORDER  ) 

Special entry point to enable the hack for generating DB2 V7.2 style WKB.

DB2 seems to have placed (and require) an extra 0x30 or'ed with the byte order in WKB. This entry point is used to turn on or off the generation of such WKB.

References OGRSetGenerate_DB2_V72_BYTE_ORDER().

Referenced by OGRSetGenerate_DB2_V72_BYTE_ORDER().

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