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OGRCurvePolygon Class Reference

Concrete class representing curve polygons. More...

#include <ogr_geometry.h>

Inheritance diagram for OGRCurvePolygon:
OGRSurface OGRGeometry OGRPolygon

List of all members.

Public Member Functions

 OGRCurvePolygon ()
 Create an empty curve polygon.
virtual const char * getGeometryName () const
 Fetch WKT name for geometry type.
virtual OGRwkbGeometryType getGeometryType () const
 Fetch geometry type.
virtual OGRGeometryclone () const
 Make a copy of this object.
virtual void empty ()
 Clear geometry information.
virtual OGRErr transform (OGRCoordinateTransformation *poCT)
 Apply arbitrary coordinate transformation to geometry.
virtual void flattenTo2D ()
 Convert geometry to strictly 2D.
virtual OGRBoolean IsEmpty () const
 Returns TRUE (non-zero) if the object has no points.
virtual void segmentize (double dfMaxLength)
 Modify the geometry such it has no segment longer then the given distance.
virtual OGRBoolean hasCurveGeometry (int bLookForNonLinear=FALSE) const
 Returns if this geometry is or has curve geometry.
virtual OGRGeometrygetLinearGeometry (double dfMaxAngleStepSizeDegrees=0, const char *const *papszOptions=NULL) const
 Return, possibly approximate, non-curve version of this geometry.
virtual double get_Area () const
 Get the area of the surface object.
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 eWkbVariant=wkbVariantOldOgc) const
 Convert a geometry into well known text format.
virtual int getDimension () const
 Get the dimension of this object.
virtual void getEnvelope (OGREnvelope *psEnvelope) const
 Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure.
virtual void getEnvelope (OGREnvelope3D *psEnvelope) const
 Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure.
virtual OGRPolygonCurvePolyToPoly (double dfMaxAngleStepSizeDegrees=0, const char *const *papszOptions=NULL) const
 Return a polygon from a curve polygon.
virtual OGRBoolean Equals (OGRGeometry *) const
 Returns TRUE if two geometries are equivalent.
virtual OGRBoolean Intersects (const OGRGeometry *) const
 Do these features intersect?
virtual OGRBoolean Contains (const OGRGeometry *) const
 Test for containment.
virtual void setCoordinateDimension (int nDimension)
 Set the coordinate dimension.
OGRErr addRing (OGRCurve *)
 Add a ring to a polygon.
OGRErr addRingDirectly (OGRCurve *)
 Add a ring to a polygon.
OGRCurvegetExteriorRingCurve ()
 Fetch reference to external polygon ring.
const OGRCurvegetExteriorRingCurve () const
int getNumInteriorRings () const
 Fetch the number of internal rings.
OGRCurvegetInteriorRingCurve (int)
 Fetch reference to indicated internal ring.
const OGRCurvegetInteriorRingCurve (int) const
OGRCurvestealExteriorRingCurve ()
 "Steal" reference to external ring.
virtual void swapXY ()
 Swap x and y coordinates.

Protected Member Functions

virtual OGRSurfaceCasterToPolygon GetCasterToPolygon () const
virtual
OGRSurfaceCasterToCurvePolygon 
GetCasterToCurvePolygon () const

Static Protected Member Functions

static OGRPolygonCastToPolygon (OGRCurvePolygon *poCP)
 Convert to polygon.

Protected Attributes

OGRCurveCollection oCC

Friends

class OGRPolygon

Detailed Description

Concrete class representing curve polygons.

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

Compatibility: ISO SQL/MM Part 3.

Since:
GDAL 2.0

Member Function Documentation

OGRErr OGRCurvePolygon::addRing ( OGRCurve poNewRing)

Add a ring to a polygon.

If the polygon has no external ring (it is empty) this will be used as the external ring, otherwise it is used as an internal ring. The passed OGRCurve remains the responsibility of the caller (an internal copy is made).

This method has no SFCOM analog.

Parameters:
poNewRingring to be added to the polygon.
Returns:
OGRERR_NONE in case of success
OGRErr OGRCurvePolygon::addRingDirectly ( OGRCurve poNewRing)

Add a ring to a polygon.

If the polygon has no external ring (it is empty) this will be used as the external ring, otherwise it is used as an internal ring. Ownership of the passed ring is assumed by the OGRCurvePolygon, but otherwise this method operates the same as OGRCurvePolygon::AddRing().

This method has no SFCOM analog.

Parameters:
poNewRingring to be added to the polygon.
Returns:
OGRERR_NONE in case of success
OGRPolygon * OGRCurvePolygon::CastToPolygon ( OGRCurvePolygon poCP) [static, protected]

Convert to polygon.

This method should only be called if the curve polygon actually only contains instances of OGRLineString. This can be verified if hasCurveGeometry(TRUE) returns FALSE. It is not intended to approximate curve polygons. For that use getLinearGeometry().

The passed in geometry is consumed and a new one returned (or NULL in case of failure).

Parameters:
poMSthe input geometry - ownership is passed to the method.
Returns:
new geometry.
OGRGeometry * OGRCurvePolygon::clone ( ) const [virtual]

Make a copy of this object.

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

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

Returns:
a new object instance with the same geometry, and spatial reference system as the original.

Implements OGRGeometry.

OGRBoolean OGRCurvePolygon::Contains ( const OGRGeometry poOtherGeom) const [virtual]

Test for containment.

Tests if actual geometry object contains the passed geometry.

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

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

Parameters:
poOtherGeomthe geometry to compare to this geometry.
Returns:
TRUE if poOtherGeom contains this geometry, otherwise FALSE.

Reimplemented from OGRGeometry.

OGRPolygon * OGRCurvePolygon::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 in OGRPolygon.

void OGRCurvePolygon::empty ( ) [virtual]

Clear geometry information.

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

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

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

Implements OGRGeometry.

OGRBoolean OGRCurvePolygon::Equals ( OGRGeometry poOtherGeom) const [virtual]

Returns TRUE if two geometries are equivalent.

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

Returns:
TRUE if equivalent or FALSE otherwise.

Implements OGRGeometry.

OGRErr OGRCurvePolygon::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.

Implements OGRGeometry.

Reimplemented in OGRPolygon.

OGRErr OGRCurvePolygon::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.

Implements OGRGeometry.

Reimplemented in OGRPolygon.

void OGRCurvePolygon::flattenTo2D ( ) [virtual]

Convert geometry to strictly 2D.

In a sense this converts all Z coordinates to 0.0.

This method is the same as the C function OGR_G_FlattenTo2D().

Implements OGRGeometry.

double OGRCurvePolygon::get_Area ( ) const [virtual]

Get the area of the surface object.

For polygons the area is computed as the area of the outer ring less the area of all internal rings.

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

Returns:
the area of the feature in square units of the spatial reference system in use.

Implements OGRSurface.

int OGRCurvePolygon::getDimension ( ) const [virtual]

Get the dimension of this object.

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

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

Returns:
0 for points, 1 for lines and 2 for surfaces.

Implements OGRGeometry.

void OGRCurvePolygon::getEnvelope ( OGREnvelope psEnvelope) const [virtual]

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

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

Parameters:
psEnvelopethe structure in which to place the results.

Implements OGRGeometry.

void OGRCurvePolygon::getEnvelope ( OGREnvelope3D psEnvelope) const [virtual]

Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure.

This method is the same as the C function OGR_G_GetEnvelope3D().

Parameters:
psEnvelopethe structure in which to place the results.
Since:
OGR 1.9.0

Implements OGRGeometry.

Fetch reference to external polygon ring.

Note that the returned ring pointer is to an internal data object of the OGRCurvePolygon. 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 OGRCurvePolygon is empty.
const char * OGRCurvePolygon::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.

Implements OGRGeometry.

Reimplemented in OGRPolygon.

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.

Implements OGRGeometry.

Reimplemented in OGRPolygon.

Fetch reference to indicated internal ring.

Note that the returned ring pointer is to an internal data object of the OGRCurvePolygon. 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 * OGRCurvePolygon::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 OGRGeometry.

Reimplemented in OGRPolygon.

Fetch the number of internal rings.

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

Returns:
count of internal rings, zero or more.
OGRBoolean OGRCurvePolygon::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 OGRGeometry.

Reimplemented in OGRPolygon.

OGRErr OGRCurvePolygon::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.

Implements OGRGeometry.

Reimplemented in OGRPolygon.

OGRErr OGRCurvePolygon::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.

Implements OGRGeometry.

Reimplemented in OGRPolygon.

OGRBoolean OGRCurvePolygon::Intersects ( const OGRGeometry poOtherGeom) const [virtual]

Do these features intersect?

Determines whether two geometries intersect. If GEOS is enabled, then this is done in rigerous fashion otherwise TRUE is returned if the envelopes (bounding boxes) of the two features overlap.

The poOtherGeom argument may be safely NULL, but in this case the method will always return TRUE. That is, a NULL geometry is treated as being everywhere.

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

Parameters:
poOtherGeomthe other geometry to test against.
Returns:
TRUE if the geometries intersect, otherwise FALSE.

Reimplemented from OGRGeometry.

OGRBoolean OGRCurvePolygon::IsEmpty ( ) const [virtual]

Returns TRUE (non-zero) if the object has no points.

Normally this returns FALSE except between when an object is instantiated and points have been assigned.

This method relates to the SFCOM IGeometry::IsEmpty() method.

Returns:
TRUE if object is empty, otherwise FALSE.

Implements OGRGeometry.

int OGRCurvePolygon::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.

Implements OGRSurface.

Reimplemented in OGRPolygon.

void OGRCurvePolygon::segmentize ( double  dfMaxLength) [virtual]

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

Add intermediate vertices to a geometry.

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 C function OGR_G_Segmentize()

Parameters:
dfMaxLengththe maximum distance between 2 points after segmentization

This method modifies the geometry to add intermediate vertices if necessary so that the maximum length between 2 consecutives vertices is lower than dfMaxLength.

Parameters:
dfMaxLengthmaximum length between 2 consecutives vertices.

Reimplemented from OGRGeometry.

void OGRCurvePolygon::setCoordinateDimension ( int  nNewDimension) [virtual]

Set the coordinate dimension.

This method sets the explicit coordinate dimension. Setting the coordinate dimension of a geometry to 2 should zero out any existing Z values. Setting the dimension of a geometry collection will not necessarily affect the children geometries.

Parameters:
nNewDimensionNew coordinate dimension value, either 2 or 3.

Reimplemented from OGRGeometry.

"Steal" reference to external ring.

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

Returns:
pointer to external ring. May be NULL if the OGRCurvePolygon is empty.
void OGRCurvePolygon::swapXY ( ) [virtual]

Swap x and y coordinates.

Since:
OGR 1.8.0

Reimplemented from OGRGeometry.

Apply arbitrary coordinate transformation to geometry.

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

Parameters:
poCTthe transformation to apply.
Returns:
OGRERR_NONE on success or an error code.

Implements OGRGeometry.

int OGRCurvePolygon::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.

Implements OGRGeometry.

Reimplemented in OGRPolygon.


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

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