QGIS API Documentation  3.14.0-Pi (9f7028fd23)
Classes | Public Types | Public Member Functions | Protected Member Functions | Protected Attributes | Friends | List of all members
QgsAbstractGeometry Class Referenceabstract

Abstract base class for all geometries. More...

#include <qgsabstractgeometry.h>

Inheritance diagram for QgsAbstractGeometry:
Inheritance graph
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Classes

class  const_part_iterator
 
class  part_iterator
 
class  vertex_iterator
 

Public Types

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 }
 WKB export flags. More...
 

Public Member Functions

 QgsAbstractGeometry ()=default
 Constructor for QgsAbstractGeometry. More...
 
 QgsAbstractGeometry (const QgsAbstractGeometry &geom)
 
virtual ~QgsAbstractGeometry ()=default
 
virtual bool addMValue (double mValue=0)=0
 Adds a measure to the geometry, initialized to a preset value. More...
 
virtual bool addZValue (double zValue=0)=0
 Adds a z-dimension to the geometry, initialized to a preset value. More...
 
virtual void adjacentVertices (QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex) const =0
 Returns the vertices adjacent to a specified vertex within a geometry. More...
 
virtual double area () const
 Returns the planar, 2-dimensional area of the geometry. More...
 
virtual QDomElement asGml2 (QDomDocument &doc, int precision=17, const QString &ns="gml", AxisOrder axisOrder=QgsAbstractGeometry::AxisOrder::XY) const =0
 Returns a GML2 representation of the geometry. More...
 
virtual QDomElement asGml3 (QDomDocument &doc, int precision=17, const QString &ns="gml", AxisOrder axisOrder=QgsAbstractGeometry::AxisOrder::XY) const =0
 Returns a GML3 representation of the geometry. More...
 
QString asJson (int precision=17)
 Returns a GeoJSON representation of the geometry as a QString. More...
 
virtual json asJsonObject (int precision=17) const
 Returns a json object representation of the geometry. More...
 
virtual QString asKml (int precision=17) const =0
 Returns a KML representation of the geometry. More...
 
virtual QByteArray asWkb (WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const =0
 Returns a WKB representation of the geometry. More...
 
virtual QString asWkt (int precision=17) const =0
 Returns a WKT representation of the geometry. More...
 
virtual QgsAbstractGeometryboundary () const =0
 Returns the closure of the combinatorial boundary of the geometry (ie the topological boundary of the geometry). More...
 
virtual QgsRectangle boundingBox () const =0
 Returns the minimal bounding box for the geometry. More...
 
virtual QgsPoint centroid () const
 Returns the centroid of the geometry. More...
 
virtual void clear ()=0
 Clears the geometry, ie reset it to a null geometry. More...
 
virtual QgsAbstractGeometryclone () const =0
 Clones the geometry by performing a deep copy. More...
 
virtual double closestSegment (const QgsPoint &pt, QgsPoint &segmentPt, QgsVertexId &vertexAfter, int *leftOf=nullptr, double epsilon=4 *std::numeric_limits< double >::epsilon()) const =0
 Searches for the closest segment of the geometry to a given point. More...
 
const_part_iterator const_parts_begin () const
 Returns STL-style iterator pointing to the const first part of the geometry. More...
 
const_part_iterator const_parts_end () const
 Returns STL-style iterator pointing to the imaginary const part after the last part of the geometry. More...
 
virtual bool convertTo (QgsWkbTypes::Type type)
 Converts the geometry to a specified type. More...
 
virtual QgsCoordinateSequence coordinateSequence () const =0
 Retrieves the sequence of geometries, rings and nodes. More...
 
virtual QgsAbstractGeometrycreateEmptyWithSameType () const =0
 Creates a new geometry with the same class and same WKB type as the original and transfers ownership. More...
 
virtual bool deleteVertex (QgsVertexId position)=0
 Deletes a vertex within the geometry. More...
 
virtual int dimension () const =0
 Returns the inherent dimension of the geometry. More...
 
virtual void draw (QPainter &p) const =0
 Draws the geometry using the specified QPainter. More...
 
virtual bool dropMValue ()=0
 Drops any measure values which exist in the geometry. More...
 
virtual bool dropZValue ()=0
 Drops any z-dimensions which exist in the geometry. More...
 
virtual void filterVertices (const std::function< bool(const QgsPoint &) > &filter)
 Filters the vertices from the geometry in place, removing any which do not return true for the filter function check. More...
 
virtual bool fromWkb (QgsConstWkbPtr &wkb)=0
 Sets the geometry from a WKB string. More...
 
virtual bool fromWkt (const QString &wkt)=0
 Sets the geometry from a WKT string. More...
 
virtual QString geometryType () const =0
 Returns a unique string representing the geometry type. More...
 
virtual bool hasCurvedSegments () const
 Returns true if the geometry contains curved segments. More...
 
virtual bool insertVertex (QgsVertexId position, const QgsPoint &vertex)=0
 Inserts a vertex into the geometry. More...
 
bool is3D () const
 Returns true if the geometry is 3D and contains a z-value. More...
 
virtual bool isEmpty () const
 Returns true if the geometry is empty. More...
 
bool isMeasure () const
 Returns true if the geometry contains m values. More...
 
virtual bool isValid (QString &error, int flags=0) const =0
 Checks validity of the geometry, and returns true if the geometry is valid. More...
 
virtual double length () const
 Returns the planar, 2-dimensional length of the geometry. More...
 
virtual bool moveVertex (QgsVertexId position, const QgsPoint &newPos)=0
 Moves a vertex within the geometry. More...
 
virtual int nCoordinates () const
 Returns the number of nodes contained in the geometry. More...
 
virtual bool nextVertex (QgsVertexId &id, QgsPoint &vertex) const =0
 Returns next vertex id and coordinates. More...
 
virtual bool operator!= (const QgsAbstractGeometry &other) const =0
 
QgsAbstractGeometryoperator= (const QgsAbstractGeometry &geom)
 
virtual bool operator== (const QgsAbstractGeometry &other) const =0
 
virtual int partCount () const =0
 Returns count of parts contained in the geometry. More...
 
QgsGeometryPartIterator parts ()
 Returns Java-style iterator for traversal of parts of the geometry. More...
 
QgsGeometryConstPartIterator parts () const
 Returns Java-style iterator for traversal of parts of the geometry. More...
 
part_iterator parts_begin ()
 Returns STL-style iterator pointing to the first part of the geometry. More...
 
part_iterator parts_end ()
 Returns STL-style iterator pointing to the imaginary part after the last part of the geometry. More...
 
virtual double perimeter () const
 Returns the planar, 2-dimensional perimeter of the geometry. More...
 
virtual bool removeDuplicateNodes (double epsilon=4 *std::numeric_limits< double >::epsilon(), bool useZValues=false)=0
 Removes duplicate nodes from the geometry, wherever removing the nodes does not result in a degenerate geometry. More...
 
virtual int ringCount (int part=0) const =0
 Returns the number of rings of which this geometry is built. More...
 
virtual QgsAbstractGeometrysegmentize (double tolerance=M_PI/180., SegmentationToleranceType toleranceType=MaximumAngle) const
 Returns a version of the geometry without curves. More...
 
virtual double segmentLength (QgsVertexId startVertex) const =0
 Returns the length of the segment of the geometry which begins at startVertex. More...
 
virtual QgsAbstractGeometrysnappedToGrid (double hSpacing, double vSpacing, double dSpacing=0, double mSpacing=0) const =0
 Makes a new geometry with all the points or vertices snapped to the closest point of the grid. More...
 
virtual void swapXy ()=0
 Swaps the x and y coordinates from the geometry. More...
 
virtual QgsAbstractGeometrytoCurveType () const =0
 Returns the geometry converted to the more generic curve type. More...
 
virtual void transform (const QgsCoordinateTransform &ct, QgsCoordinateTransform::TransformDirection d=QgsCoordinateTransform::ForwardTransform, bool transformZ=false) SIP_THROW(QgsCsException)=0
 Transforms the geometry using a coordinate transform. More...
 
virtual void transform (const QTransform &t, double zTranslate=0.0, double zScale=1.0, double mTranslate=0.0, double mScale=1.0)=0
 Transforms the x and y components of the geometry using a QTransform object t. More...
 
virtual void transformVertices (const std::function< QgsPoint(const QgsPoint &) > &transform)
 Transforms the vertices from the geometry in place, applying the transform function to every vertex. More...
 
virtual double vertexAngle (QgsVertexId vertex) const =0
 Returns approximate angle at a vertex. More...
 
virtual QgsPoint vertexAt (QgsVertexId id) const =0
 Returns the point corresponding to a specified vertex id. More...
 
virtual int vertexCount (int part=0, int ring=0) const =0
 Returns the number of vertices of which this geometry is built. More...
 
virtual int vertexNumberFromVertexId (QgsVertexId id) const =0
 Returns the vertex number corresponding to a vertex id. More...
 
QgsVertexIterator vertices () const
 Returns a read-only, Java-style iterator for traversal of vertices of all the geometry, including all geometry parts and rings. More...
 
vertex_iterator vertices_begin () const
 Returns STL-style iterator pointing to the first vertex of the geometry. More...
 
vertex_iterator vertices_end () const
 Returns STL-style iterator pointing to the imaginary vertex after the last vertex of the geometry. More...
 
QgsWkbTypes::Type wkbType () const
 Returns the WKB type of the geometry. More...
 
QString wktTypeStr () const
 Returns the WKT type string of the geometry. More...
 

Protected Member Functions

virtual QgsRectangle calculateBoundingBox () const
 Default calculator for the minimal bounding box for the geometry. More...
 
virtual int childCount () const
 Returns number of child geometries (for geometries with child geometries) or child points (for geometries without child geometries - i.e. More...
 
virtual QgsAbstractGeometrychildGeometry (int index) const
 Returns pointer to child geometry (for geometries with child geometries - i.e. More...
 
virtual QgsPoint childPoint (int index) const
 Returns point at index (for geometries without child geometries - i.e. More...
 
virtual void clearCache () const
 Clears any cached parameters associated with the geometry, e.g., bounding boxes. More...
 
virtual bool hasChildGeometries () const
 Returns whether the geometry has any child geometries (false for point / curve, true otherwise) More...
 
void setZMTypeFromSubGeometry (const QgsAbstractGeometry *subggeom, QgsWkbTypes::Type baseGeomType)
 Updates the geometry type based on whether sub geometries contain z or m values. More...
 

Protected Attributes

QgsWkbTypes::Type mWkbType = QgsWkbTypes::Unknown
 

Friends

class TestQgsGeometry
 

Detailed Description

Abstract base class for all geometries.

Note
QgsAbstractGeometry objects are inherently Cartesian/planar geometries. They have no concept of geodesy, and none of the methods or properties exposed from the QgsAbstractGeometry API (or QgsGeometry API) utilize geodesic calculations. Accordingly, properties like length() and area() and spatial operations like centroid() are always calculated using strictly Cartesian mathematics. In contrast, the QgsDistanceArea class exposes methods for working with geodesic calculations and spatial operations on geometries, and should be used whenever calculations which account for the curvature of the Earth (or any other celestial body) are required.
Since
QGIS 2.10

Definition at line 71 of file qgsabstractgeometry.h.

Member Enumeration Documentation

◆ AxisOrder

Axis order for GML generation.

Enumerator
XY 

X comes before Y (or lon before lat)

YX 

Y comes before X (or lat before lon)

Definition at line 128 of file qgsabstractgeometry.h.

◆ SegmentationToleranceType

Segmentation tolerance as maximum angle or maximum difference between approximation and circle.

Enumerator
MaximumAngle 

Maximum angle between generating radii (lines from arc center to output vertices)

MaximumDifference 

Maximum distance between an arbitrary point on the original curve and closest point on its approximation.

Definition at line 112 of file qgsabstractgeometry.h.

◆ WkbFlag

WKB export flags.

Since
QGIS 3.14
Enumerator
FlagExportTrianglesAsPolygons 

Triangles should be exported as polygon geometries.

Definition at line 245 of file qgsabstractgeometry.h.

Constructor & Destructor Documentation

◆ QgsAbstractGeometry() [1/2]

QgsAbstractGeometry::QgsAbstractGeometry ( )
default

Constructor for QgsAbstractGeometry.

◆ ~QgsAbstractGeometry()

virtual QgsAbstractGeometry::~QgsAbstractGeometry ( )
virtualdefault

◆ QgsAbstractGeometry() [2/2]

QgsAbstractGeometry::QgsAbstractGeometry ( const QgsAbstractGeometry geom)

Definition at line 28 of file qgsabstractgeometry.cpp.

Member Function Documentation

◆ addMValue()

virtual bool QgsAbstractGeometry::addMValue ( double  mValue = 0)
pure virtual

Adds a measure to the geometry, initialized to a preset value.

Parameters
mValueinitial m-value for all nodes
Returns
true on success
See also
dropMValue()
addZValue()
Since
QGIS 2.12

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ addZValue()

virtual bool QgsAbstractGeometry::addZValue ( double  zValue = 0)
pure virtual

Adds a z-dimension to the geometry, initialized to a preset value.

Parameters
zValueinitial z-value for all nodes
Returns
true on success
See also
dropZValue()
addMValue()
Since
QGIS 2.12

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ adjacentVertices()

virtual void QgsAbstractGeometry::adjacentVertices ( QgsVertexId  vertex,
QgsVertexId previousVertex,
QgsVertexId nextVertex 
) const
pure virtual

Returns the vertices adjacent to a specified vertex within a geometry.

Since
QGIS 3.0

Implemented in QgsPoint, QgsCurvePolygon, QgsCurve, and QgsGeometryCollection.

◆ area()

double QgsAbstractGeometry::area ( ) const
virtual

Returns the planar, 2-dimensional area of the geometry.

Warning
QgsAbstractGeometry objects are inherently Cartesian/planar geometries, and the area returned by this method is calculated using strictly Cartesian mathematics. In contrast, the QgsDistanceArea class exposes methods for calculating the areas of geometries using geodesic calculations which account for the curvature of the Earth (or any other celestial body).
See also
length()
perimeter()

Reimplemented in QgsGeometryCollection, and QgsCurvePolygon.

Definition at line 142 of file qgsabstractgeometry.cpp.

◆ asGml2()

virtual QDomElement QgsAbstractGeometry::asGml2 ( QDomDocument &  doc,
int  precision = 17,
const QString &  ns = "gml",
AxisOrder  axisOrder = QgsAbstractGeometry::AxisOrder::XY 
) const
pure virtual

Returns a GML2 representation of the geometry.

Parameters
docDOM document
precisionnumber of decimal places for coordinates
nsXML namespace
axisOrderAxis order for generated GML
See also
asWkb()
asWkt()
asGml3()
asJson()

Implemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsCurvePolygon, QgsCompoundCurve, QgsMultiPoint, QgsMultiCurve, QgsMultiLineString, QgsMultiSurface, and QgsMultiPolygon.

◆ asGml3()

virtual QDomElement QgsAbstractGeometry::asGml3 ( QDomDocument &  doc,
int  precision = 17,
const QString &  ns = "gml",
AxisOrder  axisOrder = QgsAbstractGeometry::AxisOrder::XY 
) const
pure virtual

Returns a GML3 representation of the geometry.

Parameters
docDOM document
precisionnumber of decimal places for coordinates
nsXML namespace
axisOrderAxis order for generated GML
See also
asWkb()
asWkt()
asGml2()
asJson()

Implemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsTriangle, QgsCurvePolygon, QgsCompoundCurve, QgsMultiPoint, QgsMultiCurve, QgsMultiLineString, QgsMultiSurface, and QgsMultiPolygon.

◆ asJson()

QString QgsAbstractGeometry::asJson ( int  precision = 17)

Returns a GeoJSON representation of the geometry as a QString.

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

Definition at line 157 of file qgsabstractgeometry.cpp.

◆ asJsonObject()

json QgsAbstractGeometry::asJsonObject ( int  precision = 17) const
virtual

Returns a json object representation of the geometry.

See also
asWkb()
asWkt()
asGml2()
asGml3()
asJson()
Note
not available in Python bindings
Since
QGIS 3.10

Reimplemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsCurvePolygon, QgsCompoundCurve, QgsMultiPoint, QgsMultiCurve, QgsMultiLineString, QgsMultiSurface, and QgsMultiPolygon.

Definition at line 162 of file qgsabstractgeometry.cpp.

◆ asKml()

virtual QString QgsAbstractGeometry::asKml ( int  precision = 17) const
pure virtual

Returns a KML representation of the geometry.

Since
QGIS 3.12

Implemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCurve, and QgsCurvePolygon.

◆ asWkb()

virtual QByteArray QgsAbstractGeometry::asWkb ( WkbFlags  flags = QgsAbstractGeometry::WkbFlags()) const
pure virtual

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()
Since
QGIS 3.0

◆ asWkt()

virtual QString QgsAbstractGeometry::asWkt ( int  precision = 17) const
pure virtual

Returns a WKT representation of the geometry.

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

Implemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsCurvePolygon, and QgsCompoundCurve.

◆ boundary()

virtual QgsAbstractGeometry* QgsAbstractGeometry::boundary ( ) const
pure virtual

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.
Since
QGIS 3.0

Implemented in QgsPoint, QgsCurve, QgsGeometryCollection, QgsTriangle, QgsCurvePolygon, QgsPolygon, QgsMultiCurve, QgsMultiPolygon, QgsMultiPoint, and QgsMultiSurface.

◆ boundingBox()

virtual QgsRectangle QgsAbstractGeometry::boundingBox ( ) const
pure virtual

Returns the minimal bounding box for the geometry.

Implemented in QgsPoint, QgsGeometryCollection, QgsCurve, and QgsSurface.

◆ calculateBoundingBox()

QgsRectangle QgsAbstractGeometry::calculateBoundingBox ( ) const
protectedvirtual

Default calculator for the minimal bounding box for the geometry.

Derived classes should override this method if a more efficient bounding box calculation is available.

Reimplemented in QgsLineString, QgsGeometryCollection, QgsCurvePolygon, QgsCompoundCurve, and QgsCircularString.

Definition at line 85 of file qgsabstractgeometry.cpp.

◆ centroid()

QgsPoint QgsAbstractGeometry::centroid ( ) const
virtual

Returns the centroid of the geometry.

Reimplemented in QgsLineString.

Definition at line 167 of file qgsabstractgeometry.cpp.

◆ childCount()

virtual int QgsAbstractGeometry::childCount ( ) const
inlineprotectedvirtual

Returns number of child geometries (for geometries with child geometries) or child points (for geometries without child geometries - i.e.

curve / point)

Note
used for vertex_iterator implementation
Since
QGIS 3.0

Reimplemented in QgsPoint, QgsGeometryCollection, QgsCurvePolygon, and QgsCurve.

Definition at line 988 of file qgsabstractgeometry.h.

◆ childGeometry()

virtual QgsAbstractGeometry* QgsAbstractGeometry::childGeometry ( int  index) const
inlineprotectedvirtual

Returns pointer to child geometry (for geometries with child geometries - i.e.

geom. collection / polygon)

Note
used for vertex_iterator implementation
Since
QGIS 3.0

Reimplemented in QgsGeometryCollection, and QgsCurvePolygon.

Definition at line 995 of file qgsabstractgeometry.h.

◆ childPoint()

QgsPoint QgsAbstractGeometry::childPoint ( int  index) const
protectedvirtual

Returns point at index (for geometries without child geometries - i.e.

curve / point)

Note
used for vertex_iterator implementation
Since
QGIS 3.0

Reimplemented in QgsPoint, and QgsCurve.

Definition at line 292 of file qgsabstractgeometry.cpp.

◆ clear()

virtual void QgsAbstractGeometry::clear ( )
pure virtual

◆ clearCache()

void QgsAbstractGeometry::clearCache ( ) const
protectedvirtual

Clears any cached parameters associated with the geometry, e.g., bounding boxes.

Reimplemented in QgsGeometryCollection, QgsCurve, and QgsSurface.

Definition at line 112 of file qgsabstractgeometry.cpp.

◆ clone()

virtual QgsAbstractGeometry* QgsAbstractGeometry::clone ( ) const
pure virtual

◆ closestSegment()

virtual double QgsAbstractGeometry::closestSegment ( const QgsPoint pt,
QgsPoint segmentPt,
QgsVertexId vertexAfter,
int *  leftOf = nullptr,
double  epsilon = 4 *std::numeric_limits< double >::epsilon() 
) const
pure virtual

Searches for the closest segment of the geometry to a given point.

Parameters
ptspecifies the point to find closest segment to
segmentPtstorage for the closest point within the geometry
vertexAfterstorage for the ID of the vertex at the end of the closest segment
leftOfindicates whether the point lies on the left side of the geometry (-1 if point is to the left of the geometry, +1 if the point is to the right of the geometry, or 0 for cases where left/right could not be determined, e.g. point exactly on a line) false if point is to right of segment)
epsilonepsilon for segment snapping
Returns
squared distance to closest segment or negative value on error

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ const_parts_begin()

const_part_iterator QgsAbstractGeometry::const_parts_begin ( ) const
inline

Returns STL-style iterator pointing to the const first part of the geometry.

See also
const_parts_end()
Since
QGIS 3.6

Definition at line 812 of file qgsabstractgeometry.h.

◆ const_parts_end()

QgsAbstractGeometry::const_part_iterator QgsAbstractGeometry::const_parts_end ( ) const

Returns STL-style iterator pointing to the imaginary const part after the last part of the geometry.

See also
const_parts_begin()
Since
QGIS 3.6

Definition at line 276 of file qgsabstractgeometry.cpp.

◆ convertTo()

bool QgsAbstractGeometry::convertTo ( QgsWkbTypes::Type  type)
virtual

Converts the geometry to a specified type.

Returns
true if conversion was successful
Since
QGIS 2.14

Reimplemented in QgsLineString, and QgsPoint.

Definition at line 219 of file qgsabstractgeometry.cpp.

◆ coordinateSequence()

virtual QgsCoordinateSequence QgsAbstractGeometry::coordinateSequence ( ) const
pure virtual

Retrieves the sequence of geometries, rings and nodes.

Returns
coordinate sequence

Implemented in QgsPoint, QgsCurvePolygon, QgsGeometryCollection, and QgsCurve.

◆ createEmptyWithSameType()

virtual QgsAbstractGeometry* QgsAbstractGeometry::createEmptyWithSameType ( ) const
pure virtual

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()
Since
3.0

Implemented in QgsLineString, QgsPoint, QgsTriangle, QgsGeometryCollection, QgsCurvePolygon, QgsCompoundCurve, QgsCircularString, QgsPolygon, QgsMultiCurve, QgsMultiPoint, QgsMultiSurface, QgsMultiLineString, and QgsMultiPolygon.

◆ deleteVertex()

virtual bool QgsAbstractGeometry::deleteVertex ( QgsVertexId  position)
pure virtual

Deletes a vertex within the geometry.

Parameters
positionvertex id for vertex to delete
Returns
true if delete was successful
See also
insertVertex
moveVertex

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, QgsCompoundCurve, and QgsTriangle.

◆ dimension()

virtual int QgsAbstractGeometry::dimension ( ) const
pure virtual

Returns the inherent dimension of the geometry.

For example, this is 0 for a point geometry, 1 for a linestring and 2 for a polygon.

Implemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsCurvePolygon, and QgsCompoundCurve.

◆ draw()

virtual void QgsAbstractGeometry::draw ( QPainter &  p) const
pure virtual

Draws the geometry using the specified QPainter.

Parameters
pdestination QPainter

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ dropMValue()

virtual bool QgsAbstractGeometry::dropMValue ( )
pure virtual

Drops any measure values which exist in the geometry.

Returns
true if m-values were present and have been removed
See also
addMValue()
dropZValue()
Since
QGIS 2.14

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ dropZValue()

virtual bool QgsAbstractGeometry::dropZValue ( )
pure virtual

Drops any z-dimensions which exist in the geometry.

Returns
true if Z values were present and have been removed
See also
addZValue()
dropMValue()
Since
QGIS 2.14

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ filterVertices()

void QgsAbstractGeometry::filterVertices ( const std::function< bool(const QgsPoint &) > &  filter)
virtual

Filters the vertices from the geometry in place, removing any which do not return true for the filter function check.

Has no meaning when called on a single point geometry.

Depending on the filter used, this may result in an invalid geometry.

Note
Not available in Python bindings
Since
QGIS 3.2

Reimplemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCompoundCurve, QgsCircularString, and QgsMultiPoint.

Definition at line 250 of file qgsabstractgeometry.cpp.

◆ fromWkb()

virtual bool QgsAbstractGeometry::fromWkb ( QgsConstWkbPtr wkb)
pure virtual

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

Implemented in QgsTriangle, QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsCurvePolygon, QgsPolygon, and QgsCompoundCurve.

◆ fromWkt()

virtual bool QgsAbstractGeometry::fromWkt ( const QString &  wkt)
pure virtual

◆ geometryType()

virtual QString QgsAbstractGeometry::geometryType ( ) const
pure virtual

◆ hasChildGeometries()

bool QgsAbstractGeometry::hasChildGeometries ( ) const
protectedvirtual

Returns whether the geometry has any child geometries (false for point / curve, true otherwise)

Note
used for vertex_iterator implementation
Since
QGIS 3.0

Definition at line 287 of file qgsabstractgeometry.cpp.

◆ hasCurvedSegments()

bool QgsAbstractGeometry::hasCurvedSegments ( ) const
virtual

Returns true if the geometry contains curved segments.

Reimplemented in QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

Definition at line 305 of file qgsabstractgeometry.cpp.

◆ insertVertex()

virtual bool QgsAbstractGeometry::insertVertex ( QgsVertexId  position,
const QgsPoint vertex 
)
pure virtual

Inserts a vertex into the geometry.

Parameters
positionvertex id for position of inserted vertex
vertexvertex to insert
Returns
true if insert was successful
See also
moveVertex
deleteVertex

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, QgsCompoundCurve, and QgsTriangle.

◆ is3D()

bool QgsAbstractGeometry::is3D ( ) const
inline

Returns true if the geometry is 3D and contains a z-value.

See also
isMeasure

Definition at line 202 of file qgsabstractgeometry.h.

◆ isEmpty()

bool QgsAbstractGeometry::isEmpty ( ) const
virtual

Returns true if the geometry is empty.

Reimplemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

Definition at line 298 of file qgsabstractgeometry.cpp.

◆ isMeasure()

bool QgsAbstractGeometry::isMeasure ( ) const
inline

Returns true if the geometry contains m values.

See also
is3D

Definition at line 211 of file qgsabstractgeometry.h.

◆ isValid()

virtual bool QgsAbstractGeometry::isValid ( QString &  error,
int  flags = 0 
) const
pure virtual

Checks validity of the geometry, and returns true if the geometry is valid.

Parameters
errorwill be set to the validity error message
flagsindicates optional flags which control the type of validity checking performed (corresponding to QgsGeometry::ValidityFlags).
Returns
true if geometry is valid
Since
QGIS 3.8

Implemented in QgsPoint, QgsGeometryCollection, QgsCurve, QgsSurface, and QgsMultiPoint.

◆ length()

double QgsAbstractGeometry::length ( ) const
virtual

Returns the planar, 2-dimensional length of the geometry.

Warning
QgsAbstractGeometry objects are inherently Cartesian/planar geometries, and the length returned by this method is calculated using strictly Cartesian mathematics. In contrast, the QgsDistanceArea class exposes methods for calculating the lengths of geometries using geodesic calculations which account for the curvature of the Earth (or any other celestial body).
See also
area()
perimeter()

Reimplemented in QgsLineString, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

Definition at line 132 of file qgsabstractgeometry.cpp.

◆ moveVertex()

virtual bool QgsAbstractGeometry::moveVertex ( QgsVertexId  position,
const QgsPoint newPos 
)
pure virtual

Moves a vertex within the geometry.

Parameters
positionvertex id for vertex to move
newPosnew position of vertex
Returns
true if move was successful
See also
insertVertex
deleteVertex

Implemented in QgsTriangle, QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ nCoordinates()

int QgsAbstractGeometry::nCoordinates ( ) const
virtual

Returns the number of nodes contained in the geometry.

Reimplemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, and QgsMultiPoint.

Definition at line 116 of file qgsabstractgeometry.cpp.

◆ nextVertex()

virtual bool QgsAbstractGeometry::nextVertex ( QgsVertexId id,
QgsPoint vertex 
) const
pure virtual

Returns next vertex id and coordinates.

Parameters
idinitial value should be the starting vertex id. The next vertex id will be stored in this variable if found.
vertexcontainer for found node
Returns
false if at end

Implemented in QgsPoint, QgsCurvePolygon, QgsGeometryCollection, and QgsCurve.

◆ operator!=()

virtual bool QgsAbstractGeometry::operator!= ( const QgsAbstractGeometry other) const
pure virtual

◆ operator=()

QgsAbstractGeometry & QgsAbstractGeometry::operator= ( const QgsAbstractGeometry geom)

Definition at line 33 of file qgsabstractgeometry.cpp.

◆ operator==()

virtual bool QgsAbstractGeometry::operator== ( const QgsAbstractGeometry other) const
pure virtual

◆ partCount()

virtual int QgsAbstractGeometry::partCount ( ) const
pure virtual

Returns count of parts contained in the geometry.

See also
vertexCount
ringCount

Implemented in QgsPoint, QgsCurvePolygon, QgsGeometryCollection, and QgsCurve.

◆ parts() [1/2]

QgsGeometryPartIterator QgsAbstractGeometry::parts ( )

Returns Java-style iterator for traversal of parts of the geometry.

This iterator can safely be used to modify parts of the geometry.

Example

# print the WKT representation of each part in a multi-point geometry
geometry = QgsMultiPoint.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.parts():
print(part.asWkt())
# single part geometries only have one part - this loop will iterate once only
geometry = QgsLineString.fromWkt( 'LineString( 0 0, 10 10 )' )
for part in geometry.parts():
print(part.asWkt())
# parts can be modified during the iteration
geometry = QgsMultiPoint.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.parts():
part.transform(ct)
# part iteration can also be combined with vertex iteration
geometry = QgsMultiPolygon.fromWkt( 'MultiPolygon((( 0 0, 0 10, 10 10, 10 0, 0 0 ),( 5 5, 5 6, 6 6, 6 5, 5 5)),((20 2, 22 2, 22 4, 20 4, 20 2)))' )
for part in geometry.parts():
for v in part.vertices():
print(v.x(), v.y())
See also
vertices()
Since
QGIS 3.6

◆ parts() [2/2]

QgsGeometryConstPartIterator QgsAbstractGeometry::parts ( ) const

Returns Java-style iterator for traversal of parts of the geometry.

This iterator returns read-only references to parts and cannot be used to modify the parts.

Note
Not available in Python bindings
Since
QGIS 3.6

Definition at line 266 of file qgsabstractgeometry.cpp.

◆ parts_begin()

part_iterator QgsAbstractGeometry::parts_begin ( )
inline

Returns STL-style iterator pointing to the first part of the geometry.

See also
parts_end()
parts()
Since
QGIS 3.6

Definition at line 743 of file qgsabstractgeometry.h.

◆ parts_end()

QgsAbstractGeometry::part_iterator QgsAbstractGeometry::parts_end ( )

Returns STL-style iterator pointing to the imaginary part after the last part of the geometry.

See also
parts_begin()
parts()
Since
QGIS 3.6

Definition at line 260 of file qgsabstractgeometry.cpp.

◆ perimeter()

double QgsAbstractGeometry::perimeter ( ) const
virtual

Returns the planar, 2-dimensional perimeter of the geometry.

Warning
QgsAbstractGeometry objects are inherently Cartesian/planar geometries, and the perimeter returned by this method is calculated using strictly Cartesian mathematics. In contrast, the QgsDistanceArea class exposes methods for calculating the perimeters of geometries using geodesic calculations which account for the curvature of the Earth (or any other celestial body).
See also
area()
length()

Reimplemented in QgsGeometryCollection, and QgsCurvePolygon.

Definition at line 137 of file qgsabstractgeometry.cpp.

◆ removeDuplicateNodes()

virtual bool QgsAbstractGeometry::removeDuplicateNodes ( double  epsilon = 4 *std::numeric_limits< double >::epsilon(),
bool  useZValues = false 
)
pure virtual

Removes duplicate nodes from the geometry, wherever removing the nodes does not result in a degenerate geometry.

The epsilon parameter specifies the tolerance for coordinates when determining that vertices are identical.

By default, z values are not considered when detecting duplicate nodes. E.g. two nodes with the same x and y coordinate but different z values will still be considered duplicate and one will be removed. If useZValues is true, then the z values are also tested and nodes with the same x and y but different z will be maintained.

Note that duplicate nodes are not tested between different parts of a multipart geometry. E.g. a multipoint geometry with overlapping points will not be changed by this method.

The function will return true if nodes were removed, or false if no duplicate nodes were found.

Since
QGIS 3.0

Implemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsCompoundCurve, and QgsCurvePolygon.

◆ ringCount()

virtual int QgsAbstractGeometry::ringCount ( int  part = 0) const
pure virtual

Returns the number of rings of which this geometry is built.

Implemented in QgsPoint, QgsCurvePolygon, QgsGeometryCollection, and QgsCurve.

◆ segmentize()

QgsAbstractGeometry * QgsAbstractGeometry::segmentize ( double  tolerance = M_PI / 180.,
SegmentationToleranceType  toleranceType = MaximumAngle 
) const
virtual

Returns a version of the geometry without curves.

Caller takes ownership of the returned geometry.

Parameters
tolerancesegmentation tolerance
toleranceTypemaximum segmentation angle or maximum difference between approximation and curve

Reimplemented in QgsCurvePolygon, QgsGeometryCollection, and QgsCurve.

Definition at line 310 of file qgsabstractgeometry.cpp.

◆ segmentLength()

virtual double QgsAbstractGeometry::segmentLength ( QgsVertexId  startVertex) const
pure virtual

Returns the length of the segment of the geometry which begins at startVertex.

Warning
QgsAbstractGeometry objects are inherently Cartesian/planar geometries, and the lengths returned by this method are calculated using strictly Cartesian mathematics.
Since
QGIS 3.0

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, QgsCompoundCurve, and QgsMultiPoint.

◆ setZMTypeFromSubGeometry()

void QgsAbstractGeometry::setZMTypeFromSubGeometry ( const QgsAbstractGeometry subggeom,
QgsWkbTypes::Type  baseGeomType 
)
protected

Updates the geometry type based on whether sub geometries contain z or m values.

Definition at line 43 of file qgsabstractgeometry.cpp.

◆ snappedToGrid()

virtual QgsAbstractGeometry* QgsAbstractGeometry::snappedToGrid ( double  hSpacing,
double  vSpacing,
double  dSpacing = 0,
double  mSpacing = 0 
) const
pure virtual

Makes a new geometry with all the points or vertices snapped to the closest point of the grid.

Ownership is transferred to the caller.

If the gridified geometry could not be calculated nullptr will be returned. It may generate an invalid geometry (in some corner cases). It can also be thought as rounding the edges and it may be useful for removing errors.

Example

geometry->snappedToGrid(1, 1);

In this case we use a 2D grid of 1x1 to gridify. In this case, it can be thought like rounding the x and y of all the points/vertices to full units (remove all decimals).

Parameters
hSpacingHorizontal spacing of the grid (x axis). 0 to disable.
vSpacingVertical spacing of the grid (y axis). 0 to disable.
dSpacingDepth spacing of the grid (z axis). 0 (default) to disable.
mSpacingCustom dimension spacing of the grid (m axis). 0 (default) to disable.
Since
3.0

Implemented in QgsLineString, QgsPoint, QgsGeometryCollection, QgsCircularString, QgsCompoundCurve, and QgsCurvePolygon.

◆ swapXy()

virtual void QgsAbstractGeometry::swapXy ( )
pure virtual

Swaps the x and y coordinates from the geometry.

This can be used to repair geometries which have accidentally had their latitude and longitude coordinates reversed.

Since
QGIS 3.2

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ toCurveType()

virtual QgsAbstractGeometry* QgsAbstractGeometry::toCurveType ( ) const
pure virtual

Returns the geometry converted to the more generic curve type.

E.g. QgsLineString -> QgsCompoundCurve, QgsPolygon -> QgsCurvePolygon, QgsMultiLineString -> QgsMultiCurve, QgsMultiPolygon -> QgsMultiSurface

Returns
the converted geometry. Caller takes ownership

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCurve, QgsTriangle, QgsPolygon, QgsMultiLineString, QgsMultiPolygon, QgsMultiCurve, QgsMultiPoint, and QgsMultiSurface.

◆ transform() [1/2]

virtual void QgsAbstractGeometry::transform ( const QgsCoordinateTransform ct,
QgsCoordinateTransform::TransformDirection  d = QgsCoordinateTransform::ForwardTransform,
bool  transformZ = false 
)
pure virtual

Transforms the geometry using a coordinate transform.

Parameters
ctcoordinate transform
dtransformation direction
transformZset to true to also transform z coordinates. This requires that the z coordinates in the geometry represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and are expressed in its vertical units (generally meters). If false, then z coordinates will not be changed by the transform.

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ transform() [2/2]

virtual void QgsAbstractGeometry::transform ( const QTransform &  t,
double  zTranslate = 0.0,
double  zScale = 1.0,
double  mTranslate = 0.0,
double  mScale = 1.0 
)
pure virtual

Transforms the x and y components of the geometry using a QTransform object t.

Optionally, the geometry's z values can be scaled via zScale and translated via zTranslate. Similarly, m-values can be scaled via mScale and translated via mTranslate.

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ transformVertices()

void QgsAbstractGeometry::transformVertices ( const std::function< QgsPoint(const QgsPoint &) > &  transform)
virtual

Transforms the vertices from the geometry in place, applying the transform function to every vertex.

Depending on the transform used, this may result in an invalid geometry.

Transform functions are not permitted to alter the dimensionality of vertices. If a transform which adds (or removes) z/m values is desired, first call the corresponding addZValue() or addMValue() function to change the geometry's dimensionality and then transform.

Note
Not available in Python bindings
Since
QGIS 3.4

Reimplemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCompoundCurve, and QgsCircularString.

Definition at line 255 of file qgsabstractgeometry.cpp.

◆ vertexAngle()

virtual double QgsAbstractGeometry::vertexAngle ( QgsVertexId  vertex) const
pure virtual

Returns approximate angle at a vertex.

This is usually the average angle between adjacent segments, and can be pictured as the orientation of a line following the curvature of the geometry at the specified vertex.

Parameters
vertexthe vertex id
Returns
rotation in radians, clockwise from north

Implemented in QgsLineString, QgsPoint, QgsCurvePolygon, QgsGeometryCollection, QgsCircularString, and QgsCompoundCurve.

◆ vertexAt()

virtual QgsPoint QgsAbstractGeometry::vertexAt ( QgsVertexId  id) const
pure virtual

Returns the point corresponding to a specified vertex id.

Implemented in QgsPoint, QgsCurvePolygon, QgsGeometryCollection, and QgsCurve.

◆ vertexCount()

virtual int QgsAbstractGeometry::vertexCount ( int  part = 0,
int  ring = 0 
) const
pure virtual

Returns the number of vertices of which this geometry is built.

Implemented in QgsPoint, QgsCurvePolygon, QgsGeometryCollection, and QgsCurve.

◆ vertexNumberFromVertexId()

virtual int QgsAbstractGeometry::vertexNumberFromVertexId ( QgsVertexId  id) const
pure virtual

Returns the vertex number corresponding to a vertex id.

The vertex numbers start at 0, so a return value of 0 corresponds to the first vertex.

Returns -1 if a corresponding vertex could not be found.

Since
QGIS 3.0

Implemented in QgsPoint, QgsCurvePolygon, QgsCurve, QgsGeometryCollection, and QgsMultiPoint.

◆ vertices()

QgsVertexIterator QgsAbstractGeometry::vertices ( ) const

Returns a read-only, Java-style iterator for traversal of vertices of all the geometry, including all geometry parts and rings.

Warning
The iterator returns a copy of individual vertices, and accordingly geometries cannot be modified using the iterator. See transformVertices() for a safe method to modify vertices "in-place".

Example

# print the x and y coordinate for each vertex in a LineString
geometry = QgsLineString.fromWkt( 'LineString( 0 0, 1 1, 2 2)' )
for v in geometry.vertices():
print(v.x(), v.y())
# vertex iteration includes all parts and rings
geometry = QgsMultiPolygon.fromWkt( 'MultiPolygon((( 0 0, 0 10, 10 10, 10 0, 0 0 ),( 5 5, 5 6, 6 6, 6 5, 5 5)),((20 2, 22 2, 22 4, 20 4, 20 2)))' )
for v in geometry.vertices():
print(v.x(), v.y())
See also
parts()
Since
QGIS 3.0

Definition at line 282 of file qgsabstractgeometry.cpp.

◆ vertices_begin()

vertex_iterator QgsAbstractGeometry::vertices_begin ( ) const
inline

Returns STL-style iterator pointing to the first vertex of the geometry.

See also
vertices_end()
vertices()
Since
QGIS 3.0

Definition at line 886 of file qgsabstractgeometry.h.

◆ vertices_end()

vertex_iterator QgsAbstractGeometry::vertices_end ( ) const
inline

Returns STL-style iterator pointing to the imaginary vertex after the last vertex of the geometry.

See also
vertices_begin()
vertices()
Since
QGIS 3.0

Definition at line 899 of file qgsabstractgeometry.h.

◆ wkbType()

QgsWkbTypes::Type QgsAbstractGeometry::wkbType ( ) const
inline

Returns the WKB type of the geometry.

See also
geometryType
wktTypeStr

Definition at line 189 of file qgsabstractgeometry.h.

◆ wktTypeStr()

QString QgsAbstractGeometry::wktTypeStr ( ) const

Returns the WKT type string of the geometry.

See also
geometryType
wkbType

Definition at line 147 of file qgsabstractgeometry.cpp.

Friends And Related Function Documentation

◆ TestQgsGeometry

friend class TestQgsGeometry
friend

Definition at line 1023 of file qgsabstractgeometry.h.

Member Data Documentation

◆ mWkbType

QgsWkbTypes::Type QgsAbstractGeometry::mWkbType = QgsWkbTypes::Unknown
protected

Definition at line 1005 of file qgsabstractgeometry.h.


The documentation for this class was generated from the following files:
QgsMultiPolygon::fromWkt
bool fromWkt(const QString &wkt) override
Sets the geometry from a WKT string.
Definition: qgsmultipolygon.cpp:56
QgsMultiPoint::fromWkt
bool fromWkt(const QString &wkt) override
Sets the geometry from a WKT string.
Definition: qgsmultipoint.cpp:53
QgsLineString::fromWkt
bool fromWkt(const QString &wkt) override
Sets the geometry from a WKT string.
Definition: qgslinestring.cpp:427