OGR
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#include <ogr_geometry.h>
Public Member Functions | |
OGRPolygon () | |
Create an empty polygon. | |
virtual const char * | getGeometryName () const |
Fetch WKT name for geometry type. More... | |
virtual OGRwkbGeometryType | getGeometryType () const |
Fetch geometry type. More... | |
virtual OGRGeometry * | clone () const |
Make a copy of this object. More... | |
virtual void | empty () |
Clear geometry information. This restores the geometry to it's initial state after construction, and before assignment of actual geometry. More... | |
virtual OGRErr | transform (OGRCoordinateTransformation *poCT) |
Apply arbitrary coordinate transformation to geometry. More... | |
virtual void | flattenTo2D () |
Convert geometry to strictly 2D. In a sense this converts all Z coordinates to 0.0. More... | |
virtual OGRBoolean | IsEmpty () const |
Returns TRUE (non-zero) if the object has no points. More... | |
virtual void | segmentize (double dfMaxLength) |
Modify the geometry such it has no segment longer then the given distance. More... | |
virtual double | get_Area () const |
Compute area of polygon. More... | |
virtual int | PointOnSurface (OGRPoint *poPoint) const |
This method relates to the SFCOM ISurface::get_PointOnSurface() method. More... | |
virtual int | WkbSize () const |
Returns size of related binary representation. More... | |
virtual OGRErr | importFromWkb (unsigned char *, int=-1) |
Assign geometry from well known binary data. More... | |
virtual OGRErr | exportToWkb (OGRwkbByteOrder, unsigned char *, OGRwkbVariant=wkbVariantOgc) const |
Convert a geometry into well known binary format. More... | |
virtual OGRErr | importFromWkt (char **) |
Assign geometry from well known text data. More... | |
virtual OGRErr | exportToWkt (char **ppszDstText) const |
Convert a geometry into well known text format. More... | |
virtual int | getDimension () const |
Get the dimension of this object. More... | |
virtual void | getEnvelope (OGREnvelope *psEnvelope) const |
Computes and returns the bounding envelope for this geometry in the passed psEnvelope structure. More... | |
virtual void | getEnvelope (OGREnvelope3D *psEnvelope) const |
Computes and returns the bounding envelope (3D) for this geometry in the passed psEnvelope structure. More... | |
virtual OGRBoolean | Equals (OGRGeometry *) const |
Returns TRUE if two geometries are equivalent. More... | |
virtual void | setCoordinateDimension (int nDimension) |
Set the coordinate dimension. More... | |
void | addRing (OGRLinearRing *) |
Add a ring to a polygon. More... | |
void | addRingDirectly (OGRLinearRing *) |
Add a ring to a polygon. More... | |
OGRLinearRing * | getExteriorRing () |
Fetch reference to external polygon ring. More... | |
int | getNumInteriorRings () const |
Fetch the number of internal rings. More... | |
OGRLinearRing * | getInteriorRing (int) |
Fetch reference to indicated internal ring. More... | |
OGRLinearRing * | stealExteriorRing () |
"Steal" reference to external polygon ring. More... | |
OGRLinearRing * | stealInteriorRing (int) |
"Steal" reference to indicated interior ring. More... | |
virtual void | closeRings () |
Force rings to be closed. More... | |
virtual void | swapXY () |
Swap x and y coordinates. More... | |
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virtual int | getCoordinateDimension () 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... | |
virtual OGRBoolean | IsRing () const |
Test if the geometry is a ring. 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... | |
void | assignSpatialReference (OGRSpatialReference *poSR) |
Assign spatial reference to this object. More... | |
OGRSpatialReference * | getSpatialReference (void) const |
Returns spatial reference system for object. More... | |
OGRErr | transformTo (OGRSpatialReference *poSR) |
Transform geometry to new spatial reference system. More... | |
virtual OGRBoolean | Intersects (OGRGeometry *) const |
Do these features intersect? 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 | Contains (const OGRGeometry *) const |
Test for containment. More... | |
virtual OGRBoolean | Overlaps (const OGRGeometry *) const |
Test for overlap. More... | |
virtual OGRGeometry * | Boundary () const |
Compute boundary. More... | |
virtual double | Distance (const OGRGeometry *) const |
Compute distance between two geometries. More... | |
virtual OGRGeometry * | ConvexHull () const |
Compute convex hull. More... | |
virtual OGRGeometry * | Buffer (double dfDist, int nQuadSegs=30) const |
Compute buffer of geometry. More... | |
virtual OGRGeometry * | Intersection (const OGRGeometry *) const |
Compute intersection. More... | |
virtual OGRGeometry * | Union (const OGRGeometry *) const |
Compute union. More... | |
virtual OGRGeometry * | UnionCascaded () const |
Compute union using cascading. More... | |
virtual OGRGeometry * | Difference (const OGRGeometry *) const |
Compute difference. More... | |
virtual OGRGeometry * | SymDifference (const OGRGeometry *) const |
Compute symmetric difference. More... | |
virtual OGRErr | Centroid (OGRPoint *poPoint) const |
Compute the geometry centroid. More... | |
virtual OGRGeometry * | Simplify (double dTolerance) const |
Simplify the geometry. More... | |
OGRGeometry * | SimplifyPreserveTopology (double dTolerance) const |
Simplify the geometry while preserving topology. More... | |
virtual OGRGeometry * | Polygonize () const |
Polygonizes a set of sparse edges. More... | |
virtual OGRGeometry * | SymmetricDifference (const OGRGeometry *) const CPL_WARN_DEPRECATED("Non standard method. Use SymDifference() instead") |
Compute symmetric difference (deprecated) More... | |
virtual OGRGeometry * | getBoundary () const CPL_WARN_DEPRECATED("Non standard method. Use Boundary() instead") |
Compute boundary (deprecated) More... | |
Concrete class representing polygons.
Note that the OpenGIS simple features polygons consist of one outer ring, 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.
void OGRPolygon::addRing | ( | OGRLinearRing * | 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 OGRLinearRing remains the responsibility of the caller (an internal copy is made).
This method has no SFCOM analog.
poNewRing | ring to be added to the polygon. |
References OGRGeometry::getCoordinateDimension().
Referenced by clone(), and OGRLayer::SetSpatialFilterRect().
void OGRPolygon::addRingDirectly | ( | OGRLinearRing * | 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 OGRPolygon, but otherwise this method operates the same as OGRPolygon::AddRing().
This method has no SFCOM analog.
poNewRing | ring to be added to the polygon. |
References OGRGeometry::getCoordinateDimension().
Referenced by OGRGeometryFactory::createFromFgf(), OGRGeometryFactory::forceToPolygon(), OGRMultiPolygon::importFromWkt(), OGRBuildPolygonFromEdges(), and OGRGeometryFactory::organizePolygons().
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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().
Implements OGRGeometry.
References addRing(), OGRGeometry::assignSpatialReference(), OGRGeometry::getSpatialReference(), and OGRPolygon().
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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.
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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.
Referenced by importFromWkt(), and OGRPolygon().
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Returns TRUE if two geometries are equivalent.
This method is the same as the C function OGR_G_Equals().
Implements OGRGeometry.
References OGRLineString::Equals(), getExteriorRing(), OGRGeometry::getGeometryType(), getGeometryType(), getInteriorRing(), getNumInteriorRings(), OGRGeometry::IsEmpty(), and IsEmpty().
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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().
eByteOrder | One of wkbXDR or wkbNDR indicating MSB or LSB byte order respectively. |
pabyData | a buffer into which the binary representation is written. This buffer must be at least OGRGeometry::WkbSize() byte in size. |
eWkbVariant | What standard to use when exporting geometries with three dimensions (or more). The default wkbVariantOgc is the historical OGR variant. wkbVariantIso is the variant defined in ISO SQL/MM and adopted by OGC for SFSQL 1.2. |
Implements OGRGeometry.
References OGRGeometry::getCoordinateDimension(), getGeometryType(), and wkbVariantIso.
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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().
ppszDstText | a text buffer is allocated by the program, and assigned to the passed pointer. After use, *ppszDstText should be freed with OGRFree(). |
Implements OGRGeometry.
References CPLCalloc(), CPLDebug(), CPLStrdup(), OGRLineString::exportToWkt(), OGRGeometry::getCoordinateDimension(), getExteriorRing(), IsEmpty(), and OGRLineString::setCoordinateDimension().
Referenced by OGRGeometryFactory::organizePolygons().
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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.
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Compute area of polygon.
The area is computed as the area of the outer ring less the area of all internal rings.
Implements OGRSurface.
References OGRLinearRing::get_Area(), getExteriorRing(), getInteriorRing(), and getNumInteriorRings().
Referenced by OGRMultiPolygon::get_Area(), and OGRGeometryFactory::organizePolygons().
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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().
Implements OGRGeometry.
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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().
psEnvelope | the structure in which to place the results. |
Implements OGRGeometry.
References OGRLineString::getEnvelope(), and IsEmpty().
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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().
psEnvelope | the structure in which to place the results. |
Implements OGRGeometry.
References OGRLineString::getEnvelope(), and IsEmpty().
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.
Referenced by OGRGeometryFactory::createFromFgf(), OGRGeometry::dumpReadable(), Equals(), exportToWkt(), OGRGeometryFactory::forceToMultiLineString(), OGRGeometryFactory::forceToPolygon(), get_Area(), OGR_L_SetSpatialFilterRectEx(), and OGRGeometryFactory::organizePolygons().
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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().
Implements OGRGeometry.
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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().
Implements OGRGeometry.
References wkbPolygon, and wkbPolygon25D.
Referenced by Equals(), and exportToWkb().
OGRLinearRing * OGRPolygon::getInteriorRing | ( | int | iRing | ) |
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.
iRing | internal ring index from 0 to getNumInternalRings() - 1. |
Referenced by OGRGeometryFactory::createFromFgf(), OGRGeometry::dumpReadable(), Equals(), OGRGeometryFactory::forceToMultiLineString(), and get_Area().
int OGRPolygon::getNumInteriorRings | ( | ) | const |
Fetch the number of internal rings.
Relates to the SFCOM IPolygon::get_NumInteriorRings() method.
Referenced by OGRGeometryFactory::createFromFgf(), OGRGeometry::dumpReadable(), Equals(), OGRGeometryFactory::forceToMultiLineString(), OGRGeometryFactory::forceToPolygon(), get_Area(), and OGR_L_SetSpatialFilterRectEx().
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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().
pabyData | the binary input data. |
nSize | the size of pabyData in bytes, or zero if not known. |
Implements OGRGeometry.
References CPLError(), VSIMalloc2(), and wkbPolygon.
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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().
ppszInput | pointer to a pointer to the source text. The pointer is updated to pointer after the consumed text. |
Implements OGRGeometry.
References CPLRealloc(), empty(), and OGRLineString::setPoints().
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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.
Implements OGRGeometry.
Referenced by Equals(), exportToWkt(), and getEnvelope().
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This method relates to the SFCOM ISurface::get_PointOnSurface() method.
NOTE: Only implemented when GEOS included in build.
poPoint | point to be set with an internal point. |
Implements OGRSurface.
References OGRPoint::empty(), OGRPoint::getX(), OGRPoint::getY(), OGRPoint::IsEmpty(), OGR_G_PointOnSurface(), OGRPoint::setX(), and OGRPoint::setY().
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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 C function OGR_G_Segmentize()
dfMaxLength | the maximum distance between 2 points after segmentization |
Reimplemented from OGRGeometry.
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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.
nNewDimension | New coordinate dimension value, either 2 or 3. |
Reimplemented from OGRGeometry.
References OGRGeometry::setCoordinateDimension().
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.
Referenced by OGRGeometryFactory::forceToPolygon().
OGRLinearRing * OGRPolygon::stealInteriorRing | ( | int | iRing | ) |
"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.
iRing | internal ring index from 0 to getNumInternalRings() - 1. |
Referenced by OGRGeometryFactory::forceToPolygon().
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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().
poCT | the transformation to apply. |
Implements OGRGeometry.
References OGRGeometry::assignSpatialReference(), CPLDebug(), OGRCoordinateTransformation::GetTargetCS(), and OGRLineString::transform().
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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().
Implements OGRGeometry.
References OGRGeometry::getCoordinateDimension().