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OGRPolygon Class Reference

Concrete class representing polygons. More...

#include <ogr_geometry.h>

Inheritance diagram for OGRPolygon:
OGRCurvePolygon OGRSurface OGRGeometry

List of all members.

Public Member Functions

 OGRPolygon ()
 Create an empty polygon.
virtual const char * getGeometryName () const
 Fetch WKT name for geometry type.
virtual OGRwkbGeometryType getGeometryType () const
 Fetch geometry type.
virtual OGRBoolean hasCurveGeometry (int bLookForNonLinear=FALSE) const
 Returns if this geometry is or has curve geometry.
virtual OGRGeometrygetCurveGeometry (const char *const *papszOptions=NULL) const
 Return curve version of this geometry.
virtual OGRGeometrygetLinearGeometry (double dfMaxAngleStepSizeDegrees=0, const char *const *papszOptions=NULL) const
 Return, possibly approximate, non-curve version of this geometry.
virtual int PointOnSurface (OGRPoint *poPoint) const
 This method relates to the SFCOM ISurface::get_PointOnSurface() method.
virtual int WkbSize () const
 Returns size of related binary representation.
virtual OGRErr importFromWkb (unsigned char *, int=-1, OGRwkbVariant=wkbVariantOldOgc)
 Assign geometry from well known binary data.
virtual OGRErr exportToWkb (OGRwkbByteOrder, unsigned char *, OGRwkbVariant=wkbVariantOldOgc) const
 Convert a geometry into well known binary format.
virtual OGRErr importFromWkt (char **)
 Assign geometry from well known text data.
virtual OGRErr exportToWkt (char **ppszDstText, OGRwkbVariant=wkbVariantOldOgc) const
 Convert a geometry into well known text format.
virtual OGRPolygonCurvePolyToPoly (double dfMaxAngleStepSizeDegrees=0, const char *const *papszOptions=NULL) const
 Return a polygon from a curve polygon.
OGRLinearRinggetExteriorRing ()
 Fetch reference to external polygon ring.
const OGRLinearRinggetExteriorRing () const
OGRLinearRinggetInteriorRing (int)
 Fetch reference to indicated internal ring.
const OGRLinearRinggetInteriorRing (int) const
OGRLinearRingstealExteriorRing ()
 "Steal" reference to external polygon ring.
OGRLinearRingstealInteriorRing (int)
 "Steal" reference to indicated interior ring.
OGRBoolean IsPointOnSurface (const OGRPoint *) const
virtual void closeRings ()
 Force rings to be closed.

Protected Member Functions

virtual int checkRing (OGRCurve *poNewRing) const
OGRErr importFromWKTListOnly (char **ppszInput, int bHasZ, int bHasM, OGRRawPoint *&paoPoints, int &nMaxPoints, double *&padfZ)
virtual OGRSurfaceCasterToPolygon GetCasterToPolygon () const
virtual
OGRSurfaceCasterToCurvePolygon 
GetCasterToCurvePolygon () const

Static Protected Member Functions

static OGRCurvePolygonCastToCurvePolygon (OGRPolygon *poPoly)
 Cast to curve polygon.

Friends

class OGRMultiSurface

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.


Member Function Documentation

OGRCurvePolygon * OGRPolygon::CastToCurvePolygon ( OGRPolygon poPoly) [static, protected]

Cast to curve polygon.

The passed in geometry is consumed and a new one returned .

Parameters:
poPolythe input geometry - ownership is passed to the method.
Returns:
new geometry.
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 OGRFree().
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.

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.

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.

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 getNumInternalRings() - 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 ( unsigned char *  pabyData,
int  nSize = -1,
OGRwkbVariant  eWkbVariant = wkbVariantOldOgc 
) [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 zero if not known.
eWkbVariantif wkbVariantPostGIS1, special interpretation is done for curve geometries code
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.

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.

int 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.

"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.

"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 getNumInternalRings() - 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 1.7.6.1.