QGIS API Documentation 3.41.0-Master (a6c88b06562)
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Public Member Functions | Static Public Member Functions | Friends | List of all members
QgsPolygon Class Reference

Polygon geometry type. More...

#include <qgspolygon.h>

Inheritance diagram for QgsPolygon:
Inheritance graph
[legend]

Public Member Functions

 QgsPolygon ()
 Constructor for an empty polygon geometry.
 
 QgsPolygon (QgsLineString *exterior, const QList< QgsLineString * > &rings=QList< QgsLineString * >())
 Constructor for QgsPolygon, with the specified exterior ring and interior rings.
 
void addInteriorRing (QgsCurve *ring) override
 Adds an interior ring to the geometry (takes ownership)
 
QByteArray asWkb (QgsAbstractGeometry::WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const override
 Returns a WKB representation of the geometry.
 
QString asWkt (int precision=17) const override
 Returns a WKT representation of the geometry.
 
QgsAbstractGeometryboundary () const override
 Returns the closure of the combinatorial boundary of the geometry (ie the topological boundary of the geometry).
 
void clear () override
 Clears the geometry, ie reset it to a null geometry.
 
QgsPolygonclone () const override
 Clones the geometry by performing a deep copy.
 
QgsPolygoncreateEmptyWithSameType () const override
 Creates a new geometry with the same class and same WKB type as the original and transfers ownership.
 
bool fromWkb (QgsConstWkbPtr &wkb) override
 Sets the geometry from a WKB string.
 
QString geometryType () const override
 Returns a unique string representing the geometry type.
 
double pointDistanceToBoundary (double x, double y) const
 Returns the distance from a point to the boundary of the polygon (either the exterior ring or any closer interior rings).
 
void setExteriorRing (QgsCurve *ring) override
 Sets the exterior ring of the polygon.
 
QgsPolygonsurfaceToPolygon () const override
 Gets a polygon representation of this surface.
 
QgsCurvePolygontoCurveType () const override
 Returns the geometry converted to the more generic curve type QgsCurvePolygon.
 
int wkbSize (QgsAbstractGeometry::WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const override
 Returns the length of the QByteArray returned by asWkb()
 
- Public Member Functions inherited from QgsCurvePolygon
 QgsCurvePolygon ()
 
 QgsCurvePolygon (const QgsCurvePolygon &p)
 
 ~QgsCurvePolygon () override
 
bool addMValue (double mValue=0) override
 Adds a measure to the geometry, initialized to a preset value.
 
bool addZValue (double zValue=0) override
 Adds a z-dimension to the geometry, initialized to a preset value.
 
void adjacentVertices (QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex) const override
 Returns the vertices adjacent to a specified vertex within a geometry.
 
double area () const override
 Returns the planar, 2-dimensional area of the geometry.
 
QDomElement asGml2 (QDomDocument &doc, int precision=17, const QString &ns="gml", QgsAbstractGeometry::AxisOrder axisOrder=QgsAbstractGeometry::AxisOrder::XY) const override
 Returns a GML2 representation of the geometry.
 
QDomElement asGml3 (QDomDocument &doc, int precision=17, const QString &ns="gml", QgsAbstractGeometry::AxisOrder axisOrder=QgsAbstractGeometry::AxisOrder::XY) const override
 Returns a GML3 representation of the geometry.
 
json asJsonObject (int precision=17) const override
 Returns a json object representation of the geometry.
 
QString asKml (int precision=17) const override
 Returns a KML representation of the geometry.
 
QPainterPath asQPainterPath () const override
 Returns the geometry represented as a QPainterPath.
 
bool boundingBoxIntersects (const QgsBox3D &box3d) const override
 Returns true if the bounding box of this geometry intersects with a box3d.
 
double closestSegment (const QgsPoint &pt, QgsPoint &segmentPt, QgsVertexId &vertexAfter, int *leftOf=nullptr, double epsilon=4 *std::numeric_limits< double >::epsilon()) const override
 Searches for the closest segment of the geometry to a given point.
 
QgsCoordinateSequence coordinateSequence () const override
 Retrieves the sequence of geometries, rings and nodes.
 
bool deleteVertex (QgsVertexId position) override
 Deletes a vertex within the geometry.
 
int dimension () const override
 Returns the inherent dimension of the geometry.
 
void draw (QPainter &p) const override
 Draws the geometry using the specified QPainter.
 
bool dropMValue () override
 Drops any measure values which exist in the geometry.
 
bool dropZValue () override
 Drops any z-dimensions which exist in the geometry.
 
QgsCurveexteriorRing ()
 Returns a non-const pointer to the curve polygon's exterior ring.
 
const QgsCurveexteriorRing () const
 Returns the curve polygon's exterior ring.
 
void filterVertices (const std::function< bool(const QgsPoint &) > &filter) override
 Filters the vertices from the geometry in place, removing any which do not return true for the filter function check.
 
void forceClockwise ()
 Forces the polygon to respect the exterior ring is clockwise, interior rings are counter-clockwise convention.
 
void forceCounterClockwise ()
 Forces the polygon to respect the exterior ring is counter-clockwise, interior rings are clockwise convention.
 
void forceRHR ()
 Forces the geometry to respect the Right-Hand-Rule, in which the area that is bounded by the polygon is to the right of the boundary.
 
bool fromWkt (const QString &wkt) override
 Sets the geometry from a WKT string.
 
bool fuzzyDistanceEqual (const QgsAbstractGeometry &other, double epsilon=1e-8) const override
 Performs fuzzy distance comparison between this geometry and other using an epsilon.
 
bool fuzzyEqual (const QgsAbstractGeometry &other, double epsilon=1e-8) const override
 Performs fuzzy comparison between this geometry and other using an epsilon.
 
bool hasCurvedSegments () const override
 Returns true if the geometry contains curved segments.
 
bool insertVertex (QgsVertexId position, const QgsPoint &vertex) override
 Inserts a vertex into the geometry.
 
QgsCurveinteriorRing (int i)
 Retrieves an interior ring from the curve polygon.
 
const QgsCurveinteriorRing (int i) const
 Retrieves an interior ring from the curve polygon.
 
bool isEmpty () const override
 Returns true if the geometry is empty.
 
bool moveVertex (QgsVertexId position, const QgsPoint &newPos) override
 Moves a vertex within the geometry.
 
int nCoordinates () const override
 Returns the number of nodes contained in the geometry.
 
bool nextVertex (QgsVertexId &id, QgsPoint &vertex) const override
 Returns next vertex id and coordinates.
 
void normalize () final
 Reorganizes the geometry into a normalized form (or "canonical" form).
 
int numInteriorRings () const
 Returns the number of interior rings contained with the curve polygon.
 
bool operator!= (const QgsAbstractGeometry &other) const override
 
QgsCurvePolygonoperator= (const QgsCurvePolygon &p)
 
bool operator== (const QgsAbstractGeometry &other) const override
 
int partCount () const override
 Returns count of parts contained in the geometry.
 
double perimeter () const override
 Returns the planar, 2-dimensional perimeter of the geometry.
 
bool removeDuplicateNodes (double epsilon=4 *std::numeric_limits< double >::epsilon(), bool useZValues=false) override
 Removes duplicate nodes from the geometry, wherever removing the nodes does not result in a degenerate geometry.
 
bool removeInteriorRing (int ringIndex)
 Removes an interior ring from the polygon.
 
void removeInteriorRings (double minimumAllowedArea=-1)
 Removes the interior rings from the polygon.
 
void removeInvalidRings ()
 Removes any interior rings which are not valid from the polygon.
 
int ringCount (int part=0) const override
 Returns the number of rings of which this geometry is built.
 
double roundness () const
 Returns the roundness of the curve polygon.
 
QgsAbstractGeometrysegmentize (double tolerance=M_PI_2/90, SegmentationToleranceType toleranceType=MaximumAngle) const override
 Returns a geometry without curves.
 
double segmentLength (QgsVertexId startVertex) const override
 Returns the length of the segment of the geometry which begins at startVertex.
 
void setInteriorRings (const QVector< QgsCurve * > &rings)
 Sets all interior rings (takes ownership)
 
QgsCurvePolygonsimplifyByDistance (double tolerance) const override
 Simplifies the geometry by applying the Douglas Peucker simplification by distance algorithm.
 
QgsCurvePolygonsnappedToGrid (double hSpacing, double vSpacing, double dSpacing=0, double mSpacing=0, bool removeRedundantPoints=false) const override
 Makes a new geometry with all the points or vertices snapped to the closest point of the grid.
 
void swapXy () override
 Swaps the x and y coordinates from the geometry.
 
virtual QgsPolygontoPolygon (double tolerance=M_PI_2/90, SegmentationToleranceType toleranceType=MaximumAngle) const
 Returns a new polygon geometry corresponding to a segmentized approximation of the curve.
 
void transform (const QgsCoordinateTransform &ct, Qgis::TransformDirection d=Qgis::TransformDirection::Forward, bool transformZ=false) override
 Transforms the geometry using a coordinate transform.
 
void transform (const QTransform &t, double zTranslate=0.0, double zScale=1.0, double mTranslate=0.0, double mScale=1.0) override
 Transforms the x and y components of the geometry using a QTransform object t.
 
bool transform (QgsAbstractGeometryTransformer *transformer, QgsFeedback *feedback=nullptr) override
 Transforms the vertices from the geometry in place, using the specified geometry transformer object.
 
void transformVertices (const std::function< QgsPoint(const QgsPoint &) > &transform) override
 Transforms the vertices from the geometry in place, applying the transform function to every vertex.
 
double vertexAngle (QgsVertexId vertex) const override
 Returns approximate rotation angle for a vertex.
 
QgsPoint vertexAt (QgsVertexId id) const override
 Returns the point corresponding to a specified vertex id.
 
int vertexCount (int part=0, int ring=0) const override
 Returns the number of vertices of which this geometry is built.
 
int vertexNumberFromVertexId (QgsVertexId id) const override
 Returns the vertex number corresponding to a vertex id.
 
- Public Member Functions inherited from QgsSurface
QgsBox3D boundingBox3D () const override
 Returns the 3D bounding box for the geometry.
 
bool isValid (QString &error, Qgis::GeometryValidityFlags flags=Qgis::GeometryValidityFlags()) const override
 Checks validity of the geometry, and returns true if the geometry is valid.
 
- Public Member Functions inherited from QgsAbstractGeometry
 QgsAbstractGeometry ()=default
 
 QgsAbstractGeometry (const QgsAbstractGeometry &geom)
 
virtual ~QgsAbstractGeometry ()=default
 
QString asJson (int precision=17)
 Returns a GeoJSON representation of the geometry as a QString.
 
virtual QgsRectangle boundingBox () const
 Returns the minimal bounding box for the geometry.
 
virtual bool boundingBoxIntersects (const QgsRectangle &rectangle) const
 Returns true if the bounding box of this geometry intersects with a rectangle.
 
virtual QgsPoint centroid () const
 Returns the centroid of the geometry.
 
virtual int compareTo (const QgsAbstractGeometry *other) const
 Comparator for sorting of geometry.
 
const_part_iterator const_parts_begin () const
 Returns STL-style iterator pointing to the const first part of the geometry.
 
const_part_iterator const_parts_end () const
 Returns STL-style iterator pointing to the imaginary const part after the last part of the geometry.
 
virtual bool convertTo (Qgis::WkbType type)
 Converts the geometry to a specified type.
 
bool is3D () const
 Returns true if the geometry is 3D and contains a z-value.
 
bool isMeasure () const
 Returns true if the geometry contains m values.
 
virtual double length () const
 Returns the planar, 2-dimensional length of the geometry.
 
QgsAbstractGeometryoperator= (const QgsAbstractGeometry &geom)
 
QgsGeometryPartIterator parts ()
 Returns Java-style iterator for traversal of parts of the geometry.
 
QgsGeometryConstPartIterator parts () const
 Returns Java-style iterator for traversal of parts of the geometry.
 
part_iterator parts_begin ()
 Returns STL-style iterator pointing to the first part of the geometry.
 
part_iterator parts_end ()
 Returns STL-style iterator pointing to the imaginary part after the last part of the geometry.
 
virtual const QgsAbstractGeometrysimplifiedTypeRef () const
 Returns a reference to the simplest lossless representation of this geometry, e.g.
 
QgsVertexIterator vertices () const
 Returns a read-only, Java-style iterator for traversal of vertices of all the geometry, including all geometry parts and rings.
 
vertex_iterator vertices_begin () const
 Returns STL-style iterator pointing to the first vertex of the geometry.
 
vertex_iterator vertices_end () const
 Returns STL-style iterator pointing to the imaginary vertex after the last vertex of the geometry.
 
Qgis::WkbType wkbType () const
 Returns the WKB type of the geometry.
 
QString wktTypeStr () const
 Returns the WKT type string of the geometry.
 

Static Public Member Functions

static const QgsPolygoncast (const QgsAbstractGeometry *geom)
 Cast the geom to a QgsPolygonV2.
 
- Static Public Member Functions inherited from QgsCurvePolygon
static const QgsCurvePolygoncast (const QgsAbstractGeometry *geom)
 Cast the geom to a QgsCurvePolygon.
 
- Static Public Member Functions inherited from QgsSurface
static const QgsSurfacecast (const QgsAbstractGeometry *geom)
 Cast the geom to a QgsSurface.
 

Friends

class QgsCurvePolygon
 

Additional Inherited Members

- Public Types inherited from QgsAbstractGeometry
enum  AxisOrder { XY = 0 , YX }
 Axis order for GML generation. More...
 
enum  SegmentationToleranceType { MaximumAngle = 0 , MaximumDifference }
 Segmentation tolerance as maximum angle or maximum difference between approximation and circle. More...
 
enum  WkbFlag { FlagExportTrianglesAsPolygons = 1 << 0 , FlagExportNanAsDoubleMin = 1 << 1 }
 WKB export flags. More...
 
typedef QFlags< WkbFlagWkbFlags
 
- Protected Member Functions inherited from QgsCurvePolygon
QgsBox3D calculateBoundingBox3D () const override
 Calculates the minimal 3D bounding box for the geometry.
 
int childCount () const override
 Returns number of child geometries (for geometries with child geometries) or child points (for geometries without child geometries - i.e.
 
QgsAbstractGeometrychildGeometry (int index) const override
 Returns pointer to child geometry (for geometries with child geometries - i.e.
 
int compareToSameClass (const QgsAbstractGeometry *other) const final
 Compares to an other geometry of the same class, and returns a integer for sorting of the two geometries.
 
- Protected Member Functions inherited from QgsSurface
void clearCache () const override
 Clears any cached parameters associated with the geometry, e.g., bounding boxes.
 
- Protected Member Functions inherited from QgsAbstractGeometry
virtual QgsRectangle calculateBoundingBox () const
 Default calculator for the minimal bounding box for the geometry.
 
virtual QgsPoint childPoint (int index) const
 Returns point at index (for geometries without child geometries - i.e.
 
virtual bool hasChildGeometries () const
 Returns whether the geometry has any child geometries (false for point / curve, true otherwise)
 
void setZMTypeFromSubGeometry (const QgsAbstractGeometry *subggeom, Qgis::WkbType baseGeomType)
 Updates the geometry type based on whether sub geometries contain z or m values.
 
int sortIndex () const
 Returns the sort index for the geometry, used in the compareTo() method to compare geometries of different types.
 
- Protected Attributes inherited from QgsCurvePolygon
std::unique_ptr< QgsCurvemExteriorRing
 
QVector< QgsCurve * > mInteriorRings
 
- Protected Attributes inherited from QgsSurface
QgsBox3D mBoundingBox
 
bool mHasCachedValidity = false
 
QString mValidityFailureReason
 
- Protected Attributes inherited from QgsAbstractGeometry
Qgis::WkbType mWkbType = Qgis::WkbType::Unknown
 

Detailed Description

Polygon geometry type.

Definition at line 32 of file qgspolygon.h.

Constructor & Destructor Documentation

◆ QgsPolygon() [1/2]

QgsPolygon::QgsPolygon ( )

Constructor for an empty polygon geometry.

Definition at line 25 of file qgspolygon.cpp.

◆ QgsPolygon() [2/2]

QgsPolygon::QgsPolygon ( QgsLineString exterior,
const QList< QgsLineString * > &  rings = QList< QgsLineString * >() 
)

Constructor for QgsPolygon, with the specified exterior ring and interior rings.

Ownership of exterior and rings is transferred to the polygon.

Since
QGIS 3.14

Member Function Documentation

◆ addInteriorRing()

void QgsPolygon::addInteriorRing ( QgsCurve ring)
overridevirtual

Adds an interior ring to the geometry (takes ownership)

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 235 of file qgspolygon.cpp.

◆ asWkb()

QByteArray QgsPolygon::asWkb ( QgsAbstractGeometry::WkbFlags  flags = QgsAbstractGeometry::WkbFlags()) const
overridevirtual

Returns a WKB representation of the geometry.

The optional flags argument specifies flags controlling WKB export behavior (since QGIS 3.14).

See also
asWkt
asGml2
asGml3
asJson()

Reimplemented from QgsCurvePolygon.

Definition at line 141 of file qgspolygon.cpp.

◆ asWkt()

QString QgsPolygon::asWkt ( int  precision = 17) const
overridevirtual

Returns a WKT representation of the geometry.

Parameters
precisionnumber of decimal places for coordinates
See also
asWkb()
asGml2()
asGml3()
asJson()

Reimplemented from QgsCurvePolygon.

Definition at line 188 of file qgspolygon.cpp.

◆ boundary()

QgsAbstractGeometry * QgsPolygon::boundary ( ) const
overridevirtual

Returns the closure of the combinatorial boundary of the geometry (ie the topological boundary of the geometry).

For instance, a polygon geometry will have a boundary consisting of the linestrings for each ring in the polygon.

Returns
boundary for geometry. May be nullptr for some geometry types.

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 301 of file qgspolygon.cpp.

◆ cast()

static const QgsPolygon * QgsPolygon::cast ( const QgsAbstractGeometry geom)
inlinestatic

Cast the geom to a QgsPolygonV2.

Should be used by qgsgeometry_cast<QgsPolygon *>( geometry ).

Note
Not available in Python. Objects will be automatically be converted to the appropriate target type.

Definition at line 87 of file qgspolygon.h.

◆ clear()

void QgsPolygon::clear ( )
overridevirtual

Clears the geometry, ie reset it to a null geometry.

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 59 of file qgspolygon.cpp.

◆ clone()

QgsPolygon * QgsPolygon::clone ( ) const
overridevirtual

Clones the geometry by performing a deep copy.

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 54 of file qgspolygon.cpp.

◆ createEmptyWithSameType()

QgsPolygon * QgsPolygon::createEmptyWithSameType ( ) const
overridevirtual

Creates a new geometry with the same class and same WKB type as the original and transfers ownership.

To create it, the geometry is default constructed and then the WKB is changed.

See also
clone()

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 47 of file qgspolygon.cpp.

◆ fromWkb()

bool QgsPolygon::fromWkb ( QgsConstWkbPtr wkb)
overridevirtual

Sets the geometry from a WKB string.

After successful read the wkb argument will be at the position where the reading has stopped.

See also
fromWkt

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 65 of file qgspolygon.cpp.

◆ geometryType()

QString QgsPolygon::geometryType ( ) const
overridevirtual

Returns a unique string representing the geometry type.

See also
wkbType
wktTypeStr

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 42 of file qgspolygon.cpp.

◆ pointDistanceToBoundary()

double QgsPolygon::pointDistanceToBoundary ( double  x,
double  y 
) const

Returns the distance from a point to the boundary of the polygon (either the exterior ring or any closer interior rings).

The returned distance will be negative if the point lies outside the polygon.

Definition at line 324 of file qgspolygon.cpp.

◆ setExteriorRing()

void QgsPolygon::setExteriorRing ( QgsCurve ring)
overridevirtual

Sets the exterior ring of the polygon.

The CurvePolygon type will be updated to match the dimensionality of the exterior ring. For instance, setting a 2D exterior ring on a 3D CurvePolygon will drop the z dimension from the CurvePolygon and all interior rings.

Parameters
ringnew exterior ring. Ownership is transferred to the CurvePolygon.
See also
setInteriorRings()
exteriorRing()

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 266 of file qgspolygon.cpp.

◆ surfaceToPolygon()

QgsPolygon * QgsPolygon::surfaceToPolygon ( ) const
overridevirtual

Gets a polygon representation of this surface.

Ownership is transferred to the caller.

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 358 of file qgspolygon.cpp.

◆ toCurveType()

QgsCurvePolygon * QgsPolygon::toCurveType ( ) const
overridevirtual

Returns the geometry converted to the more generic curve type QgsCurvePolygon.

Returns
the converted geometry. Caller takes ownership

Reimplemented from QgsCurvePolygon.

Reimplemented in QgsTriangle.

Definition at line 363 of file qgspolygon.cpp.

◆ wkbSize()

int QgsPolygon::wkbSize ( QgsAbstractGeometry::WkbFlags  flags = QgsAbstractGeometry::WkbFlags()) const
overridevirtual

Returns the length of the QByteArray returned by asWkb()

The optional flags argument specifies flags controlling WKB export behavior

Since
QGIS 3.16

Reimplemented from QgsCurvePolygon.

Definition at line 124 of file qgspolygon.cpp.

Friends And Related Symbol Documentation

◆ QgsCurvePolygon

friend class QgsCurvePolygon
friend

Definition at line 116 of file qgspolygon.h.


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