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OGRPolygon Class Reference

Concrete class representing polygons. More...

#include <ogr_geometry.h>

Inheritance diagram for OGRPolygon:
OGRCurvePolygon OGRSurface OGRGeometry OGRTriangle

Public Member Functions

 OGRPolygon ()
 Create an empty polygon.
 
 OGRPolygon (const OGRPolygon &other)
 Copy constructor. More...
 
OGRPolygonoperator= (const OGRPolygon &other)
 Assignment operator. More...
 
virtual const char * getGeometryName () const CPL_OVERRIDE
 Fetch WKT name for geometry type. More...
 
virtual OGRwkbGeometryType getGeometryType () const CPL_OVERRIDE
 Fetch geometry type. More...
 
virtual OGRBoolean hasCurveGeometry (int bLookForNonLinear=FALSE) const CPL_OVERRIDE
 Returns if this geometry is or has curve geometry. More...
 
virtual OGRGeometrygetCurveGeometry (const char *const *papszOptions=NULL) const CPL_OVERRIDE
 Return curve version of this geometry. More...
 
virtual OGRGeometrygetLinearGeometry (double dfMaxAngleStepSizeDegrees=0, const char *const *papszOptions=NULL) const CPL_OVERRIDE
 Return, possibly approximate, non-curve version of this geometry. More...
 
virtual OGRErr PointOnSurface (OGRPoint *poPoint) const CPL_OVERRIDE
 This method relates to the SFCOM ISurface::get_PointOnSurface() method. More...
 
virtual int WkbSize () const CPL_OVERRIDE
 Returns size of related binary representation. More...
 
virtual OGRErr importFromWkb (const unsigned char *, int, OGRwkbVariant, int &nBytesConsumedOut) CPL_OVERRIDE
 Assign geometry from well known binary data. More...
 
virtual OGRErr exportToWkb (OGRwkbByteOrder, unsigned char *, OGRwkbVariant=wkbVariantOldOgc) const CPL_OVERRIDE
 Convert a geometry into well known binary format. More...
 
virtual OGRErr importFromWkt (char **) CPL_OVERRIDE
 Assign geometry from well known text data. More...
 
virtual OGRErr exportToWkt (char **ppszDstText, OGRwkbVariant=wkbVariantOldOgc) const CPL_OVERRIDE
 Convert a geometry into well known text format. More...
 
virtual OGRPolygonCurvePolyToPoly (double dfMaxAngleStepSizeDegrees=0, const char *const *papszOptions=NULL) const CPL_OVERRIDE
 Return a polygon from a curve polygon. More...
 
OGRLinearRinggetExteriorRing ()
 Fetch reference to external polygon ring. More...
 
const OGRLinearRinggetExteriorRing () const
 Fetch reference to external polygon ring. More...
 
virtual OGRLinearRinggetInteriorRing (int)
 Fetch reference to indicated internal ring. More...
 
virtual const OGRLinearRinggetInteriorRing (int) const
 Fetch reference to indicated internal ring. More...
 
OGRLinearRingstealExteriorRing ()
 "Steal" reference to external polygon ring. More...
 
virtual OGRLinearRingstealInteriorRing (int)
 "Steal" reference to indicated interior ring. More...
 
OGRBoolean IsPointOnSurface (const OGRPoint *) const
 Return whether the point is on the surface. More...
 
virtual void closeRings () CPL_OVERRIDE
 Force rings to be closed. More...
 
- Public Member Functions inherited from OGRCurvePolygon
 OGRCurvePolygon ()
 Create an empty curve polygon.
 
 OGRCurvePolygon (const OGRCurvePolygon &)
 Copy constructor. More...
 
OGRCurvePolygonoperator= (const OGRCurvePolygon &other)
 Assignment operator. More...
 
virtual OGRGeometryclone () const CPL_OVERRIDE
 Make a copy of this object. More...
 
virtual void empty () CPL_OVERRIDE
 Clear geometry information. More...
 
virtual OGRErr transform (OGRCoordinateTransformation *poCT) CPL_OVERRIDE
 Apply arbitrary coordinate transformation to geometry. More...
 
virtual void flattenTo2D () CPL_OVERRIDE
 Convert geometry to strictly 2D. More...
 
virtual OGRBoolean IsEmpty () const CPL_OVERRIDE
 Returns TRUE (non-zero) if the object has no points. More...
 
virtual void segmentize (double dfMaxLength) CPL_OVERRIDE
 Modify the geometry such it has no segment longer then the given distance. More...
 
virtual double get_Area () const CPL_OVERRIDE
 Get the area of the surface object. More...
 
virtual int getDimension () const CPL_OVERRIDE
 Get the dimension of this object. More...
 
virtual void getEnvelope (OGREnvelope *psEnvelope) const CPL_OVERRIDE
 Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure. More...
 
virtual void getEnvelope (OGREnvelope3D *psEnvelope) const CPL_OVERRIDE
 Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure. More...
 
virtual OGRBoolean Equals (OGRGeometry *) const CPL_OVERRIDE
 Returns TRUE if two geometries are equivalent. More...
 
virtual OGRBoolean Intersects (const OGRGeometry *) const CPL_OVERRIDE
 Do these features intersect? More...
 
virtual OGRBoolean Contains (const OGRGeometry *) const CPL_OVERRIDE
 Test for containment. More...
 
virtual void setCoordinateDimension (int nDimension) CPL_OVERRIDE
 Set the coordinate dimension. More...
 
virtual void set3D (OGRBoolean bIs3D) CPL_OVERRIDE
 Add or remove the Z coordinate dimension. More...
 
virtual void setMeasured (OGRBoolean bIsMeasured) CPL_OVERRIDE
 Add or remove the M coordinate dimension. More...
 
virtual OGRErr addRing (OGRCurve *)
 Add a ring to a polygon. More...
 
virtual OGRErr addRingDirectly (OGRCurve *)
 Add a ring to a polygon. More...
 
OGRCurvegetExteriorRingCurve ()
 Fetch reference to external polygon ring. More...
 
const OGRCurvegetExteriorRingCurve () const
 Fetch reference to external polygon ring. More...
 
int getNumInteriorRings () const
 Fetch the number of internal rings. More...
 
OGRCurvegetInteriorRingCurve (int)
 Fetch reference to indicated internal ring. More...
 
const OGRCurvegetInteriorRingCurve (int) const
 Fetch reference to indicated internal ring. More...
 
OGRCurvestealExteriorRingCurve ()
 "Steal" reference to external ring. More...
 
virtual void swapXY () CPL_OVERRIDE
 Swap x and y coordinates. More...
 
- Public Member Functions inherited from OGRGeometry
 OGRGeometry (const OGRGeometry &other)
 Copy constructor. More...
 
OGRGeometryoperator= (const OGRGeometry &other)
 Assignment operator. More...
 
virtual int getCoordinateDimension () const
 Get the dimension of the coordinates in this object. More...
 
int CoordinateDimension () const
 Get the dimension of the coordinates in this object. More...
 
virtual OGRBoolean IsValid () const
 Test if the geometry is valid. More...
 
virtual OGRBoolean IsSimple () const
 Test if the geometry is simple. More...
 
OGRBoolean Is3D () const
 
OGRBoolean IsMeasured () const
 
virtual OGRBoolean IsRing () const
 Test if the geometry is a ring. More...
 
OGRErr importFromWkb (unsigned char *, int=-1, OGRwkbVariant=wkbVariantOldOgc)
 Assign geometry from well known binary data. More...
 
OGRwkbGeometryType getIsoGeometryType () const
 Get the geometry type that conforms with ISO SQL/MM Part3. More...
 
virtual void dumpReadable (FILE *, const char *=NULL, char **papszOptions=NULL) const
 Dump geometry in well known text format to indicated output file. More...
 
virtual char * exportToGML (const char *const *papszOptions=NULL) const
 Convert a geometry into GML format. More...
 
virtual char * exportToKML () const
 Convert a geometry into KML format. More...
 
virtual char * exportToJson () const
 Convert a geometry into GeoJSON format. More...
 
virtual GEOSGeom exportToGEOS (GEOSContextHandle_t hGEOSCtxt) const CPL_WARN_UNUSED_RESULT
 Returns a GEOSGeom object corresponding to the geometry. More...
 
void assignSpatialReference (OGRSpatialReference *poSR)
 Assign spatial reference to this object. More...
 
OGRSpatialReferencegetSpatialReference (void) const
 Returns spatial reference system for object. More...
 
OGRErr transformTo (OGRSpatialReference *poSR)
 Transform geometry to new spatial reference system. More...
 
virtual OGRBoolean Disjoint (const OGRGeometry *) const
 Test for disjointness. More...
 
virtual OGRBoolean Touches (const OGRGeometry *) const
 Test for touching. More...
 
virtual OGRBoolean Crosses (const OGRGeometry *) const
 Test for crossing. More...
 
virtual OGRBoolean Within (const OGRGeometry *) const
 Test for containment. More...
 
virtual OGRBoolean Overlaps (const OGRGeometry *) const
 Test for overlap. More...
 
virtual OGRGeometryBoundary () const CPL_WARN_UNUSED_RESULT
 Compute boundary. More...
 
virtual double Distance (const OGRGeometry *) const
 Compute distance between two geometries. More...
 
virtual OGRGeometryConvexHull () const CPL_WARN_UNUSED_RESULT
 Compute convex hull. More...
 
virtual OGRGeometryBuffer (double dfDist, int nQuadSegs=30) const CPL_WARN_UNUSED_RESULT
 Compute buffer of geometry. More...
 
virtual OGRGeometryIntersection (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT
 Compute intersection. More...
 
virtual OGRGeometryUnion (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT
 Compute union. More...
 
virtual OGRGeometryUnionCascaded () const CPL_WARN_UNUSED_RESULT
 Compute union using cascading. More...
 
virtual OGRGeometryDifference (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT
 Compute difference. More...
 
virtual OGRGeometrySymDifference (const OGRGeometry *) const CPL_WARN_UNUSED_RESULT
 Compute symmetric difference. More...
 
virtual OGRErr Centroid (OGRPoint *poPoint) const
 Compute the geometry centroid. More...
 
virtual OGRGeometrySimplify (double dTolerance) const CPL_WARN_UNUSED_RESULT
 Simplify the geometry. More...
 
OGRGeometrySimplifyPreserveTopology (double dTolerance) const CPL_WARN_UNUSED_RESULT
 Simplify the geometry while preserving topology. More...
 
virtual OGRGeometryDelaunayTriangulation (double dfTolerance, int bOnlyEdges) const CPL_WARN_UNUSED_RESULT
 Return a Delaunay triangulation of the vertices of the geometry. More...
 
virtual OGRGeometryPolygonize () const CPL_WARN_UNUSED_RESULT
 Polygonizes a set of sparse edges. More...
 
virtual double Distance3D (const OGRGeometry *poOtherGeom) const
 Returns the 3D distance between two geometries. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from OGRGeometry
static GEOSContextHandle_t createGEOSContext ()
 Create a new GEOS context. More...
 
static void freeGEOSContext (GEOSContextHandle_t hGEOSCtxt)
 Destroy a GEOS context. More...
 
- Static Protected Member Functions inherited from OGRCurvePolygon
static OGRPolygonCastToPolygon (OGRCurvePolygon *poCP)
 Convert to polygon. More...
 

Detailed Description

Concrete class representing polygons.

Note that the OpenGIS simple features polygons consist of one outer ring (linearring), and zero or more inner rings. A polygon cannot represent disconnected regions (such as multiple islands in a political body). The OGRMultiPolygon must be used for this.

Constructor & Destructor Documentation

OGRPolygon::OGRPolygon ( const OGRPolygon other)

Copy constructor.

Note: before GDAL 2.1, only the default implementation of the constructor existed, which could be unsafe to use.

Since
GDAL 2.1

Member Function Documentation

void OGRPolygon::closeRings ( )
virtual

Force rings to be closed.

If this geometry, or any contained geometries has polygon rings that are not closed, they will be closed by adding the starting point at the end.

Reimplemented from OGRGeometry.

OGRPolygon * OGRPolygon::CurvePolyToPoly ( double  dfMaxAngleStepSizeDegrees = 0,
const char *const *  papszOptions = NULL 
) const
virtual

Return a polygon from a curve polygon.

This method is the same as C function OGR_G_CurvePolyToPoly().

The returned geometry is a new instance whose ownership belongs to the caller.

Parameters
dfMaxAngleStepSizeDegreesthe largest step in degrees along the arc, zero to use the default setting.
papszOptionsoptions as a null-terminated list of strings. Unused for now. Must be set to NULL.
Returns
a linestring
Since
OGR 2.0

Reimplemented from OGRCurvePolygon.

OGRErr OGRPolygon::exportToWkb ( OGRwkbByteOrder  eByteOrder,
unsigned char *  pabyData,
OGRwkbVariant  eWkbVariant = wkbVariantOldOgc 
) const
virtual

Convert a geometry into well known binary format.

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

This method is the same as the C function OGR_G_ExportToWkb() or OGR_G_ExportToIsoWkb(), depending on the value of eWkbVariant.

Parameters
eByteOrderOne of wkbXDR or wkbNDR indicating MSB or LSB byte order respectively.
pabyDataa buffer into which the binary representation is written. This buffer must be at least OGRGeometry::WkbSize() byte in size.
eWkbVariantWhat standard to use when exporting geometries with three dimensions (or more). The default wkbVariantOldOgc is the historical OGR variant. wkbVariantIso is the variant defined in ISO SQL/MM and adopted by OGC for SFSQL 1.2.
Returns
Currently OGRERR_NONE is always returned.

Reimplemented from OGRCurvePolygon.

OGRErr OGRPolygon::exportToWkt ( char **  ppszDstText,
OGRwkbVariant  eWkbVariant = wkbVariantOldOgc 
) const
virtual

Convert a geometry into well known text format.

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

This method is the same as the C function OGR_G_ExportToWkt().

Parameters
ppszDstTexta text buffer is allocated by the program, and assigned to the passed pointer. After use, *ppszDstText should be freed with CPLFree().
eWkbVariantthe specification that must be conformed too :
  • wbkVariantOgc for old-style 99-402 extended dimension (Z) WKB types
  • wbkVariantIso for SFSQL 1.2 and ISO SQL/MM Part 3
Returns
Currently OGRERR_NONE is always returned.

Reimplemented from OGRCurvePolygon.

OGRGeometry * OGRPolygon::getCurveGeometry ( const char *const *  papszOptions = NULL) const
virtual

Return curve version of this geometry.

Returns a geometry that has possibly CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE in it, by de-approximating curve geometries.

If the geometry has no curve portion, the returned geometry will be a clone of it.

The ownership of the returned geometry belongs to the caller.

The reverse method is OGRGeometry::getLinearGeometry().

This function is the same as C function OGR_G_GetCurveGeometry().

Parameters
papszOptionsoptions as a null-terminated list of strings. Unused for now. Must be set to NULL.
Returns
a new geometry.
Since
GDAL 2.0

Reimplemented from OGRGeometry.

OGRLinearRing * OGRPolygon::getExteriorRing ( )

Fetch reference to external polygon ring.

Note that the returned ring pointer is to an internal data object of the OGRPolygon. It should not be modified or deleted by the application, and the pointer is only valid till the polygon is next modified. Use the OGRGeometry::clone() method to make a separate copy within the application.

Relates to the SFCOM IPolygon::get_ExteriorRing() method.

Returns
pointer to external ring. May be NULL if the OGRPolygon is empty.
const OGRLinearRing * OGRPolygon::getExteriorRing ( ) const

Fetch reference to external polygon ring.

Note that the returned ring pointer is to an internal data object of the OGRPolygon. It should not be modified or deleted by the application, and the pointer is only valid till the polygon is next modified. Use the OGRGeometry::clone() method to make a separate copy within the application.

Relates to the SFCOM IPolygon::get_ExteriorRing() method.

Returns
pointer to external ring. May be NULL if the OGRPolygon is empty.
const char * OGRPolygon::getGeometryName ( ) const
virtual

Fetch WKT name for geometry type.

There is no SFCOM analog to this method.

This method is the same as the C function OGR_G_GetGeometryName().

Returns
name used for this geometry type in well known text format. The returned pointer is to a static internal string and should not be modified or freed.

Reimplemented from OGRCurvePolygon.

Reimplemented in OGRTriangle.

OGRwkbGeometryType OGRPolygon::getGeometryType ( ) const
virtual

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 method is the same as the C function OGR_G_GetGeometryType().

Returns
the geometry type code.

Reimplemented from OGRCurvePolygon.

Reimplemented in OGRTriangle.

OGRLinearRing * OGRPolygon::getInteriorRing ( int  iRing)
virtual

Fetch reference to indicated internal ring.

Note that the returned ring pointer is to an internal data object of the OGRPolygon. It should not be modified or deleted by the application, and the pointer is only valid till the polygon is next modified. Use the OGRGeometry::clone() method to make a separate copy within the application.

Relates to the SFCOM IPolygon::get_InternalRing() method.

Parameters
iRinginternal ring index from 0 to getNumInteriorRings() - 1.
Returns
pointer to interior ring. May be NULL.
const OGRLinearRing * OGRPolygon::getInteriorRing ( int  iRing) const
virtual

Fetch reference to indicated internal ring.

Note that the returned ring pointer is to an internal data object of the OGRPolygon. It should not be modified or deleted by the application, and the pointer is only valid till the polygon is next modified. Use the OGRGeometry::clone() method to make a separate copy within the application.

Relates to the SFCOM IPolygon::get_InternalRing() method.

Parameters
iRinginternal ring index from 0 to getNumInteriorRings() - 1.
Returns
pointer to interior ring. May be NULL.
OGRGeometry * OGRPolygon::getLinearGeometry ( double  dfMaxAngleStepSizeDegrees = 0,
const char *const *  papszOptions = NULL 
) const
virtual

Return, possibly approximate, non-curve version of this geometry.

Returns a geometry that has no CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE in it, by approximating curve geometries.

The ownership of the returned geometry belongs to the caller.

The reverse method is OGRGeometry::getCurveGeometry().

This method is the same as the C function OGR_G_GetLinearGeometry().

Parameters
dfMaxAngleStepSizeDegreesthe largest step in degrees along the arc, zero to use the default setting.
papszOptionsoptions as a null-terminated list of strings. See OGRGeometryFactory::curveToLineString() for valid options.
Returns
a new geometry.
Since
GDAL 2.0

Reimplemented from OGRCurvePolygon.

OGRBoolean OGRPolygon::hasCurveGeometry ( int  bLookForNonLinear = FALSE) const
virtual

Returns if this geometry is or has curve geometry.

Returns if a geometry is, contains or may contain a CIRCULARSTRING, COMPOUNDCURVE, CURVEPOLYGON, MULTICURVE or MULTISURFACE.

If bLookForNonLinear is set to TRUE, it will be actually looked if the geometry or its subgeometries are or contain a non-linear geometry in them. In which case, if the method returns TRUE, it means that getLinearGeometry() would return an approximate version of the geometry. Otherwise, getLinearGeometry() would do a conversion, but with just converting container type, like COMPOUNDCURVE -> LINESTRING, MULTICURVE -> MULTILINESTRING or MULTISURFACE -> MULTIPOLYGON, resulting in a "loss-less" conversion.

This method is the same as the C function OGR_G_HasCurveGeometry().

Parameters
bLookForNonLinearset it to TRUE to check if the geometry is or contains a CIRCULARSTRING.
Returns
TRUE if this geometry is or has curve geometry.
Since
GDAL 2.0

Reimplemented from OGRCurvePolygon.

OGRErr OGRPolygon::importFromWkb ( const unsigned char *  pabyData,
int  nSize,
OGRwkbVariant  eWkbVariant,
int &  nBytesConsumedOut 
)
virtual

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 method is used by the OGRGeometryFactory class, but not normally called by application code.

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

This method is the same as the C function OGR_G_ImportFromWkb().

Parameters
pabyDatathe binary input data.
nSizethe size of pabyData in bytes, or -1 if not known.
eWkbVariantif wkbVariantPostGIS1, special interpretation is done for curve geometries code
nBytesConsumedOutoutput parameter. Number of bytes consumed.
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.
Since
GDAL 2.3

Reimplemented from OGRCurvePolygon.

Reimplemented in OGRTriangle.

OGRErr OGRPolygon::importFromWkt ( char **  ppszInput)
virtual

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 method is used by the OGRGeometryFactory class, but not normally called by application code.

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

This method is the same as the C function OGR_G_ImportFromWkt().

Parameters
ppszInputpointer 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.

Reimplemented from OGRCurvePolygon.

OGRBoolean OGRPolygon::IsPointOnSurface ( const OGRPoint pt) const

Return whether the point is on the surface.

Returns
TRUE or FALSE
OGRPolygon & OGRPolygon::operator= ( const OGRPolygon other)

Assignment operator.

Note: before GDAL 2.1, only the default implementation of the operator existed, which could be unsafe to use.

Since
GDAL 2.1
OGRErr OGRPolygon::PointOnSurface ( OGRPoint poPoint) const
virtual

This method relates to the SFCOM ISurface::get_PointOnSurface() method.

NOTE: Only implemented when GEOS included in build.

Parameters
poPointpoint to be set with an internal point.
Returns
OGRERR_NONE if it succeeds or OGRERR_FAILURE otherwise.

Reimplemented from OGRCurvePolygon.

OGRLinearRing * OGRPolygon::stealExteriorRing ( )

"Steal" reference to external polygon ring.

After the call to that function, only call to stealInteriorRing() or destruction of the OGRPolygon is valid. Other operations may crash.

Returns
pointer to external ring. May be NULL if the OGRPolygon is empty.
OGRLinearRing * OGRPolygon::stealInteriorRing ( int  iRing)
virtual

"Steal" reference to indicated interior ring.

After the call to that function, only call to stealInteriorRing() or destruction of the OGRPolygon is valid. Other operations may crash.

Parameters
iRinginternal ring index from 0 to getNumInteriorRings() - 1.
Returns
pointer to interior ring. May be NULL.
int OGRPolygon::WkbSize ( ) const
virtual

Returns size of related binary representation.

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

This method is the same as the C function OGR_G_WkbSize().

Returns
size of binary representation in bytes.

Reimplemented from OGRCurvePolygon.


The documentation for this class was generated from the following files:

Generated for GDAL by doxygen 1.8.8.