Circular string geometry type. More...

#include <qgscircularstring.h>

Inheritance diagram for QgsCircularString:

[legend]

Public Member Functions
	QgsCircularString ()
	Constructs an empty circular string.

	QgsCircularString (const QgsPoint &p1, const QgsPoint &p2, const QgsPoint &p3)
	Constructs a circular string with a single arc passing through p1, p2 and p3.

	QgsCircularString (const QVector< double > &x, const QVector< double > &y, const QVector< double > &z=QVector< double >(), const QVector< double > &m=QVector< double >())
	Construct a circular string from arrays of coordinates.

bool	addMValue (double mValue=0) override
	Adds a measure to the geometry, initialized to a preset value.

void	addToPainterPath (QPainterPath &path) const override
	Adds a curve to a painter path.

bool	addZValue (double zValue=0) override
	Adds a z-dimension to the geometry, initialized to a preset value.

void	append (const QgsCircularString *string)
	Appends the contents of another circular string to the end of this circular string.

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.

QByteArray	asWkb (QgsAbstractGeometry::WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const override

QString	asWkt (int precision=17) const override
	Returns a WKT representation of the geometry.

void	clear () override
	Clears the geometry, ie reset it to a null geometry.

QgsCircularString *	clone () const override
	Clones the geometry by performing a deep copy.

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.

QgsCircularString *	createEmptyWithSameType () const override
	Creates a new geometry with the same class and same WKB type as the original and transfers ownership.

QgsCircularString *	curveSubstring (double startDistance, double endDistance) const override
	Returns a new curve representing a substring of this curve.

QgsLineString *	curveToLine (double tolerance=M_PI_2/90, SegmentationToleranceType toleranceType=MaximumAngle) const override
	Returns a new line string geometry corresponding to a segmentized approximation of the curve.

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.

void	drawAsPolygon (QPainter &p) const override
	Draws the curve as a polygon on 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.

QgsPoint	endPoint () const override
	Returns the end point of the curve.

bool	equals (const QgsCurve &other) const override
	Checks whether this curve exactly equals another curve.

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.

bool	fromWkb (QgsConstWkbPtr &wkb) override
	Sets the geometry from a WKB string.

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.

QString	geometryType () const override
	Returns a unique string representing the geometry type.

bool	hasCurvedSegments () const override
	Returns `true` if the geometry contains curved segments.

int	indexOf (const QgsPoint &point) const final
	Returns the index of the first vertex matching the given point, or -1 if a matching vertex is not found.

bool	insertVertex (QgsVertexId position, const QgsPoint &vertex) override
	Inserts a vertex into the geometry.

QgsPoint *	interpolatePoint (double distance) const override
	Returns an interpolated point on the curve at the specified distance.

bool	isEmpty () const override
	Returns `true` if the geometry is empty.

bool	isValid (QString &error, Qgis::GeometryValidityFlags flags=Qgis::GeometryValidityFlags()) const override
	Checks validity of the geometry, and returns `true` if the geometry is valid.

double	length () const override
	Returns the planar, 2-dimensional length of the geometry.

double	mAt (int index) const override
	Returns the m-coordinate of the specified node in the line string.

bool	moveVertex (QgsVertexId position, const QgsPoint &newPos) override
	Moves a vertex within the geometry.

int	numPoints () const override
	Returns the number of points in the curve.

bool	pointAt (int node, QgsPoint &point, Qgis::VertexType &type) const override
	Returns the point and vertex id of a point within the curve.

QgsPoint	pointN (int i) const
	Returns the point at index i within the circular string.

void	points (QgsPointSequence &pts) const override
	Returns a list of points within the curve.

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.

QgsCircularString *	reversed () const override
	Returns a reversed copy of the curve, where the direction of the curve has been flipped.

void	scroll (int firstVertexIndex) final
	Scrolls the curve vertices so that they start with the vertex at the given index.

double	segmentLength (QgsVertexId startVertex) const override
	Returns the length of the segment of the geometry which begins at startVertex.

void	setPoints (const QgsPointSequence &points)
	Sets the circular string's points.

QgsCircularString *	snappedToGrid (double hSpacing, double vSpacing, double dSpacing=0, double mSpacing=0) const override
	Makes a new geometry with all the points or vertices snapped to the closest point of the grid.

std::tuple< std::unique_ptr< QgsCurve >, std::unique_ptr< QgsCurve > >	splitCurveAtVertex (int index) const final
	Splits the curve at the specified vertex index, returning two curves which represent the portion of the curve up to an including the vertex at index, and the portion of the curve from the vertex at index (inclusive) to the end of the curve.

QgsPoint	startPoint () const override
	Returns the starting point of the curve.

void	sumUpArea (double &sum) const override
	Sums up the area of the curve by iterating over the vertices (shoelace formula).

void	swapXy () override
	Swaps the x and y coordinates from the geometry.

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 angle at a vertex.

int	wkbSize (QgsAbstractGeometry::WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const override
	Returns the length of the QByteArray returned by asWkb()

double	xAt (int index) const override
	Returns the x-coordinate of the specified node in the line string.

double	yAt (int index) const override
	Returns the y-coordinate of the specified node in the line string.

double	zAt (int index) const override
	Returns the z-coordinate of the specified node in the line string.

Public Member Functions inherited from QgsCurve
	QgsCurve ()=default
	Constructor for QgsCurve.

void	adjacentVertices (QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex) const override
	Returns the vertices adjacent to a specified vertex within a 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.

virtual QPolygonF	asQPolygonF () const
	Returns a QPolygonF representing the points.

QgsAbstractGeometry *	boundary () const override
	Returns the closure of the combinatorial boundary of the geometry (ie the topological boundary of the geometry).

QgsBox3D	boundingBox3D () const override
	Returns the 3D bounding box for the geometry.

QgsCoordinateSequence	coordinateSequence () const override
	Retrieves the sequence of geometries, rings and nodes.

virtual bool	isClosed () const
	Returns `true` if the curve is closed.

virtual bool	isClosed2D () const
	Returns true if the curve is closed.

virtual bool	isRing () const
	Returns `true` if the curve is a ring.

bool	isValid (QString &error, Qgis::GeometryValidityFlags flags=Qgis::GeometryValidityFlags()) const override
	Checks validity of the geometry, and returns `true` if the geometry is valid.

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).

bool	operator!= (const QgsAbstractGeometry &other) const override

bool	operator== (const QgsAbstractGeometry &other) const override

Qgis::AngularDirection	orientation () const
	Returns the curve's orientation, e.g.

int	partCount () const override
	Returns count of parts contained in the geometry.

int	ringCount (int part=0) const override
	Returns the number of rings of which this geometry is built.

QgsCurve *	segmentize (double tolerance=M_PI_2/90, SegmentationToleranceType toleranceType=MaximumAngle) const override
	Returns a geometry without curves.

double	sinuosity () const
	Returns the curve sinuosity, which is the ratio of the curve length() to curve straightDistance2d().

double	straightDistance2d () const
	Returns the straight distance of the curve, i.e.

QgsCurve *	toCurveType () const override
	Returns the geometry converted to the more generic curve type.

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 QgsAbstractGeometry
	QgsAbstractGeometry ()=default
	Constructor for QgsAbstractGeometry.

	QgsAbstractGeometry (const QgsAbstractGeometry &geom)

virtual	~QgsAbstractGeometry ()=default

virtual double	area () const
	Returns the planar, 2-dimensional area of the geometry.

QString	asJson (int precision=17)
	Returns a GeoJSON representation of the geometry as a QString.

virtual QByteArray	asWkb (WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const =0
	Returns a WKB representation of the geometry.

virtual QgsRectangle	boundingBox () const
	Returns the minimal bounding box for the geometry.

virtual bool	boundingBoxIntersects (const QgsBox3D &box3d) const
	Returns `true` if the bounding box of this geometry intersects with a box3d.

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 int	nCoordinates () const
	Returns the number of nodes contained in the geometry.

QgsAbstractGeometry &	operator= (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 double	perimeter () const
	Returns the planar, 2-dimensional perimeter of the geometry.

virtual const QgsAbstractGeometry *	simplifiedTypeRef () 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 QgsCircularString *	cast (const QgsAbstractGeometry *geom)
	Cast the geom to a QgsCircularString.

static QgsCircularString	fromTwoPointsAndCenter (const QgsPoint &p1, const QgsPoint &p2, const QgsPoint &center, bool useShortestArc=true)
	Creates a circular string with a single arc representing the curve from p1 to p2 with the specified center.

Static Public Member Functions inherited from QgsCurve
static const QgsCurve *	cast (const QgsAbstractGeometry *geom)
	Cast the geom to a QgsCurve.

Protected Member Functions
QgsBox3D	calculateBoundingBox3D () const override
	Calculates the minimal 3D bounding box for the geometry.

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 QgsCurve
int	childCount () const override
	Returns number of child geometries (for geometries with child geometries) or child points (for geometries without child geometries - i.e.

QgsPoint	childPoint (int index) const override
	Returns point at index (for geometries without child geometries - i.e.

void	clearCache () const override
	Clears any cached parameters associated with the geometry, e.g., bounding boxes.

bool	snapToGridPrivate (double hSpacing, double vSpacing, double dSpacing, double mSpacing, const QVector< double > &srcX, const QVector< double > &srcY, const QVector< double > &srcZ, const QVector< double > &srcM, QVector< double > &outX, QVector< double > &outY, QVector< double > &outZ, QVector< double > &outM) const
	Helper function for QgsCurve subclasses to snap to grids.

Protected Member Functions inherited from QgsAbstractGeometry
virtual QgsRectangle	calculateBoundingBox () const
	Default calculator for the minimal bounding box for the geometry.

virtual QgsAbstractGeometry *	childGeometry (int index) const
	Returns pointer to child geometry (for geometries with 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.

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...

Protected Attributes inherited from QgsCurve
QgsBox3D	mBoundingBox
	Cached bounding box.

bool	mHasCachedSummedUpArea = false

double	mSummedUpArea = 0

Protected Attributes inherited from QgsAbstractGeometry
Qgis::WkbType	mWkbType = Qgis::WkbType::Unknown

Detailed Description

Circular string geometry type.

Definition at line 33 of file qgscircularstring.h.

Constructor & Destructor Documentation

◆ QgsCircularString() [1/3]

QgsCircularString::QgsCircularString ( )

Constructs an empty circular string.

Definition at line 36 of file qgscircularstring.cpp.

◆ QgsCircularString() [2/3]

QgsCircularString::QgsCircularString	(	const QgsPoint &	p1,
		const QgsPoint &	p2,
		const QgsPoint &	p3
	)

Constructs a circular string with a single arc passing through p1, p2 and p3.

Since: QGIS 3.2

Definition at line 41 of file qgscircularstring.cpp.

◆ QgsCircularString() [3/3]

QgsCircularString::QgsCircularString	(	const QVector< double > &	x,
		const QVector< double > &	y,
		const QVector< double > &	z = `QVector<double>()`,
		const QVector< double > &	m = `QVector<double>()`
	)

Construct a circular string from arrays of coordinates.

If the z or m arrays are non-empty then the resultant circular string will have z and m types accordingly.

This constructor is more efficient then calling setPoints().

If the sizes of x and y are non-equal then the resultant circular string will be created using the minimum size of these arrays.

Warning: It is the caller's responsibility to ensure that the supplied arrays are of odd sizes.

Since: QGIS 3.20

Definition at line 74 of file qgscircularstring.cpp.

Member Function Documentation

◆ addMValue()

bool QgsCircularString::addMValue ( double mValue = 0 )

overridevirtual

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

Parameters

mValue initial m-value for all nodes

Returns: true on success

See also: dropMValue(); addZValue()

Implements QgsAbstractGeometry.

Definition at line 1821 of file qgscircularstring.cpp.

◆ addToPainterPath()

void QgsCircularString::addToPainterPath ( QPainterPath & path ) const

overridevirtual

Adds a curve to a painter path.

Implements QgsCurve.

Definition at line 1182 of file qgscircularstring.cpp.

◆ addZValue()

bool QgsCircularString::addZValue ( double zValue = 0 )

overridevirtual

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

Parameters

zValue initial z-value for all nodes

Returns: true on success

See also: dropZValue(); addMValue()

Implements QgsAbstractGeometry.

Definition at line 1803 of file qgscircularstring.cpp.

◆ append()

void QgsCircularString::append ( const QgsCircularString * string )

Appends the contents of another circular string to the end of this circular string.

Parameters

string circular string to append. Ownership is not transferred.

Warning: It is the caller's responsibility to ensure that the first point in the appended string matches the last point in the existing curve, or the result will be undefined.

Since: QGIS 3.20

Definition at line 1049 of file qgscircularstring.cpp.

◆ asGml2()

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

overridevirtual

Returns a GML2 representation of the geometry.

Parameters

doc	DOM document
precision	number of decimal places for coordinates
ns	XML namespace
axisOrder	Axis order for generated GML

See also: asWkb(); asWkt(); asGml3(); asJson()

Implements QgsAbstractGeometry.

Definition at line 533 of file qgscircularstring.cpp.

◆ asGml3()

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

overridevirtual

Returns a GML3 representation of the geometry.

Parameters

doc	DOM document
precision	number of decimal places for coordinates
ns	XML namespace
axisOrder	Axis order for generated GML

See also: asWkb(); asWkt(); asGml2(); asJson()

Implements QgsAbstractGeometry.

Definition at line 541 of file qgscircularstring.cpp.

◆ asJsonObject()

json QgsCircularString::asJsonObject ( int precision = 17 ) const

overridevirtual

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 from QgsAbstractGeometry.

Definition at line 560 of file qgscircularstring.cpp.

◆ asWkb()

QByteArray QgsCircularString::asWkb ( QgsAbstractGeometry::WkbFlags flags = QgsAbstractGeometry::WkbFlags() ) const

override

Definition at line 505 of file qgscircularstring.cpp.

◆ asWkt()

QString QgsCircularString::asWkt ( int precision = 17 ) const

overridevirtual

Returns a WKT representation of the geometry.

Parameters

precision number of decimal places for coordinates

See also: asWkb(); asGml2(); asGml3(); asJson()

Implements QgsAbstractGeometry.

Definition at line 518 of file qgscircularstring.cpp.

◆ calculateBoundingBox3D()

QgsBox3D QgsCircularString::calculateBoundingBox3D ( ) const

overrideprotectedvirtual

Calculates the minimal 3D bounding box for the geometry.

See also: calculateBoundingBox()

Since: QGIS 3.34

Reimplemented from QgsAbstractGeometry.

Definition at line 244 of file qgscircularstring.cpp.

◆ cast()

static const QgsCircularString * QgsCircularString::cast ( const QgsAbstractGeometry * geom )

inlinestatic

Cast the geom to a QgsCircularString.

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

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

Definition at line 306 of file qgscircularstring.h.

◆ clear()

void QgsCircularString::clear ( )

overridevirtual

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

Implements QgsAbstractGeometry.

Definition at line 234 of file qgscircularstring.cpp.

◆ clone()

QgsCircularString * QgsCircularString::clone ( ) const

overridevirtual

Clones the geometry by performing a deep copy.

Implements QgsCurve.

Definition at line 229 of file qgscircularstring.cpp.

◆ closestSegment()

double QgsCircularString::closestSegment	(	const QgsPoint &	pt,
		QgsPoint &	segmentPt,
		QgsVertexId &	vertexAfter,
		int *	leftOf = `nullptr`,
		double	epsilon = `4 *std::numeric_limits< double >::epsilon()`
	)		const

overridevirtual

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

Parameters

pt	specifies the point to find closest segment to
segmentPt	storage for the closest point within the geometry
vertexAfter	storage for the ID of the vertex at the end of the closest segment
leftOf	indicates 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)
epsilon	epsilon for segment snapping

Returns: squared distance to closest segment or negative value on error

Implements QgsAbstractGeometry.

Definition at line 1308 of file qgscircularstring.cpp.

◆ compareToSameClass()

int QgsCircularString::compareToSameClass ( const QgsAbstractGeometry * other ) const

finalprotectedvirtual

Compares to an other geometry of the same class, and returns a integer for sorting of the two geometries.

Note: The actual logic for the sorting is an internal detail only and is subject to change between QGIS versions. The result should only be used for direct comparison of geometries and not stored for later use.

Since: QGIS 3.20

Implements QgsAbstractGeometry.

Definition at line 133 of file qgscircularstring.cpp.

◆ createEmptyWithSameType()

QgsCircularString * QgsCircularString::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()

Implements QgsAbstractGeometry.

Definition at line 126 of file qgscircularstring.cpp.

◆ curveSubstring()

QgsCircularString * QgsCircularString::curveSubstring	(	double	startDistance,
		double	endDistance
	)		const

overridevirtual

Returns a new curve representing a substring of this curve.

The startDistance and endDistance arguments specify the length along the curve which the substring should start and end at. If the endDistance is greater than the total length of the curve then any "extra" length will be ignored.

If z or m values are present, the output z and m will be interpolated using the existing vertices' z or m values.

Since: QGIS 3.4

Implements QgsCurve.

Definition at line 1673 of file qgscircularstring.cpp.

◆ curveToLine()

QgsLineString * QgsCircularString::curveToLine	(	double	tolerance = `M_PI_2/90`,
		SegmentationToleranceType	toleranceType = `MaximumAngle`
	)		const

overridevirtual

Returns a new line string geometry corresponding to a segmentized approximation of the curve.

Parameters

tolerance	segmentation tolerance
toleranceType	maximum segmentation angle or maximum difference between approximation and curve

Uses a MaximumAngle tolerance of 1 degrees by default (360 segments in a full circle)

Implements QgsCurve.

Definition at line 612 of file qgscircularstring.cpp.

◆ deleteVertex()

bool QgsCircularString::deleteVertex ( QgsVertexId position )

overridevirtual

Deletes a vertex within the geometry.

Parameters

position vertex id for vertex to delete

Returns: true if delete was successful

See also: insertVertex; moveVertex

Implements QgsAbstractGeometry.

Definition at line 1264 of file qgscircularstring.cpp.

◆ dimension()

int QgsCircularString::dimension ( ) const

overridevirtual

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.

Implements QgsAbstractGeometry.

Definition at line 224 of file qgscircularstring.cpp.

◆ draw()

void QgsCircularString::draw ( QPainter & p ) const

overridevirtual

Draws the geometry using the specified QPainter.

Parameters

p	destination QPainter

Implements QgsAbstractGeometry.

Definition at line 1114 of file qgscircularstring.cpp.

◆ drawAsPolygon()

void QgsCircularString::drawAsPolygon ( QPainter & p ) const

overridevirtual

Draws the curve as a polygon on the specified QPainter.

Parameters

p	destination QPainter

Implements QgsCurve.

Definition at line 1207 of file qgscircularstring.cpp.

◆ dropMValue()

bool QgsCircularString::dropMValue ( )

overridevirtual

Drops any measure values which exist in the geometry.

Returns: true if m-values were present and have been removed

See also: addMValue(); dropZValue()

Implements QgsAbstractGeometry.

Definition at line 1851 of file qgscircularstring.cpp.

◆ dropZValue()

bool QgsCircularString::dropZValue ( )

overridevirtual

Drops any z-dimensions which exist in the geometry.

Returns: true if Z values were present and have been removed

See also: addZValue(); dropMValue()

Implements QgsAbstractGeometry.

Definition at line 1839 of file qgscircularstring.cpp.

◆ endPoint()

QgsPoint QgsCircularString::endPoint ( ) const

overridevirtual

Returns the end point of the curve.

See also: startPoint

Implements QgsCurve.

Definition at line 603 of file qgscircularstring.cpp.

◆ equals()

bool QgsCircularString::equals ( const QgsCurve & other ) const

inlineoverridevirtual

Checks whether this curve exactly equals another curve.

Implements QgsCurve.

Definition at line 209 of file qgscircularstring.h.

◆ filterVertices()

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

overridevirtual

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 from QgsAbstractGeometry.

Definition at line 849 of file qgscircularstring.cpp.

◆ fromTwoPointsAndCenter()

QgsCircularString QgsCircularString::fromTwoPointsAndCenter	(	const QgsPoint &	p1,
		const QgsPoint &	p2,
		const QgsPoint &	center,
		bool	useShortestArc = `true`
	)

static

Creates a circular string with a single arc representing the curve from p1 to p2 with the specified center.

If useShortestArc is true, then the arc returned will be that corresponding to the shorter arc from p1 to p2. If it is false, the longer arc from p1 to p2 will be used (i.e. winding the other way around the circle).

Since: QGIS 3.2

Definition at line 120 of file qgscircularstring.cpp.

◆ fromWkb()

bool QgsCircularString::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

Implements QgsAbstractGeometry.

Definition at line 428 of file qgscircularstring.cpp.

◆ fromWkt()

bool QgsCircularString::fromWkt ( const QString & wkt )

overridevirtual

Sets the geometry from a WKT string.

See also: fromWkb

Implements QgsAbstractGeometry.

Definition at line 473 of file qgscircularstring.cpp.

◆ fuzzyDistanceEqual()

bool QgsCircularString::fuzzyDistanceEqual	(	const QgsAbstractGeometry &	other,
		double	epsilon = `1e-8`
	)		const

inlineoverridevirtual

Performs fuzzy distance comparison between this geometry and other using an epsilon.

Traditionally, the comparison is done by examining the specific values (such as x and y) that define the location of vertices in the geometry. It focuses on the numerical differences or relationships between these values. On the other hand, comparing distances between points considers the actual spatial separation or length between the points, regardless of their coordinate values. This comparison involves measuring the distance between two points using formulas like the distance formula. Here, it's the "distance comparison" (fuzzyDistanceEqual).

See also: fuzzyEqual; QgsGeometryUtilsBase::fuzzyEqual

Since: QGIS 3.36

Implements QgsAbstractGeometry.

Definition at line 180 of file qgscircularstring.h.

◆ fuzzyEqual()

bool QgsCircularString::fuzzyEqual	(	const QgsAbstractGeometry &	other,
		double	epsilon = `1e-8`
	)		const

inlineoverridevirtual

Performs fuzzy comparison between this geometry and other using an epsilon.

The comparison is done by examining the specific values (such as x and y) that define the location of vertices in the geometry.

See also: fuzzyDistanceEqual; QgsGeometryUtilsBase::fuzzyDistanceEqual

Since: QGIS 3.36

Implements QgsAbstractGeometry.

Definition at line 151 of file qgscircularstring.h.

◆ geometryType()

QString QgsCircularString::geometryType ( ) const

overridevirtual

Returns a unique string representing the geometry type.

See also: wkbType; wktTypeStr

Implements QgsAbstractGeometry.

Definition at line 219 of file qgscircularstring.cpp.

◆ hasCurvedSegments()

bool QgsCircularString::hasCurvedSegments ( ) const

overridevirtual

Returns true if the geometry contains curved segments.

Reimplemented from QgsAbstractGeometry.

Definition at line 1428 of file qgscircularstring.cpp.

◆ indexOf()

int QgsCircularString::indexOf ( const QgsPoint & point ) const

finalvirtual

Returns the index of the first vertex matching the given point, or -1 if a matching vertex is not found.

Note: If the curve has m or z values then the search point must have exactly matching m and z values in order to be matched against the curve's vertices.; This method only matches against segment vertices, not curve vertices.

Since: QGIS 3.20

Implements QgsCurve.

Definition at line 696 of file qgscircularstring.cpp.

◆ insertVertex()

bool QgsCircularString::insertVertex	(	QgsVertexId	position,
		const QgsPoint &	vertex
	)

overridevirtual

Inserts a vertex into the geometry.

Parameters

position	vertex id for position of inserted vertex
vertex	vertex to insert

Returns: true if insert was successful

See also: moveVertex; deleteVertex

Implements QgsAbstractGeometry.

Definition at line 1212 of file qgscircularstring.cpp.

◆ interpolatePoint()

QgsPoint * QgsCircularString::interpolatePoint ( double distance ) const

overridevirtual

Returns an interpolated point on the curve at the specified distance.

If z or m values are present, the output z and m will be interpolated using the existing vertices' z or m values.

If distance is negative, or is greater than the length of the curve, nullptr will be returned.

Since: QGIS 3.4

Implements QgsCurve.

Definition at line 1604 of file qgscircularstring.cpp.

◆ isEmpty()

bool QgsCircularString::isEmpty ( ) const

overridevirtual

Returns true if the geometry is empty.

Reimplemented from QgsAbstractGeometry.

Definition at line 567 of file qgscircularstring.cpp.

◆ isValid()

bool QgsCircularString::isValid	(	QString &	error,
		Qgis::GeometryValidityFlags	flags = `Qgis::GeometryValidityFlags()`
	)		const

overridevirtual

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

Parameters

error	will be set to the validity error message
flags	indicates optional flags which control the type of validity checking performed (corresponding to Qgis::GeometryValidityFlags).

Returns: true if geometry is valid

Since: QGIS 3.8

Implements QgsAbstractGeometry.

Definition at line 572 of file qgscircularstring.cpp.

◆ length()

double QgsCircularString::length ( ) const

overridevirtual

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 from QgsAbstractGeometry.

Definition at line 583 of file qgscircularstring.cpp.

◆ mAt()

double QgsCircularString::mAt ( int index ) const

overridevirtual

Returns the m-coordinate of the specified node in the line string.

Parameters

index index of node, where the first node in the line is 0

Returns: m-coordinate of node, or 0.0 if index is out of bounds

Since: QGIS 3.28

Implements QgsCurve.

Definition at line 797 of file qgscircularstring.cpp.

◆ moveVertex()

bool QgsCircularString::moveVertex	(	QgsVertexId	position,
		const QgsPoint &	newPos
	)

overridevirtual

Moves a vertex within the geometry.

Parameters

position	vertex id for vertex to move
newPos	new position of vertex

Returns: true if move was successful

See also: insertVertex; deleteVertex

Implements QgsAbstractGeometry.

Definition at line 1243 of file qgscircularstring.cpp.

◆ numPoints()

int QgsCircularString::numPoints ( ) const

overridevirtual

Returns the number of points in the curve.

Implements QgsCurve.

Definition at line 691 of file qgscircularstring.cpp.

◆ pointAt()

bool QgsCircularString::pointAt	(	int	node,
		QgsPoint &	point,
		Qgis::VertexType &	type
	)		const

overridevirtual

Returns the point and vertex id of a point within the curve.

Parameters

node	node number, where the first node is 0
point	will be set to point at corresponding node in the curve
type	will be set to the vertex type of the node

Returns: true if node exists within the curve

Implements QgsCurve.

Definition at line 1347 of file qgscircularstring.cpp.

◆ pointN()

QgsPoint QgsCircularString::pointN ( int i ) const

Returns the point at index i within the circular string.

Definition at line 736 of file qgscircularstring.cpp.

◆ points()

void QgsCircularString::points ( QgsPointSequence & pt ) const

overridevirtual

Returns a list of points within the curve.

Implements QgsCurve.

Definition at line 982 of file qgscircularstring.cpp.

◆ removeDuplicateNodes()

bool QgsCircularString::removeDuplicateNodes	(	double	epsilon = `4 *std::numeric_limits< double >::epsilon()`,
		bool	useZValues = `false`
	)

overridevirtual

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.

Implements QgsAbstractGeometry.

Definition at line 640 of file qgscircularstring.cpp.

◆ reversed()

QgsCircularString * QgsCircularString::reversed ( ) const

overridevirtual

Returns a reversed copy of the curve, where the direction of the curve has been flipped.

Implements QgsCurve.

Definition at line 1588 of file qgscircularstring.cpp.

◆ scroll()

void QgsCircularString::scroll ( int firstVertexIndex )

finalvirtual

Scrolls the curve vertices so that they start with the vertex at the given index.

Warning: This should only be called on closed curves, or the shape of the curve will be altered and the result is undefined.; The firstVertexIndex must correspond to a segment vertex and not a curve point or the result is undefined.

Since: QGIS 3.20

Implements QgsCurve.

Definition at line 288 of file qgscircularstring.cpp.

◆ segmentLength()

double QgsCircularString::segmentLength ( QgsVertexId startVertex ) const

overridevirtual

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.

Implements QgsAbstractGeometry.

Definition at line 1571 of file qgscircularstring.cpp.

◆ setPoints()

void QgsCircularString::setPoints ( const QgsPointSequence & points )

Sets the circular string's points.

Definition at line 992 of file qgscircularstring.cpp.

◆ snappedToGrid()

QgsCircularString * QgsCircularString::snappedToGrid	(	double	hSpacing,
		double	vSpacing,
		double	dSpacing = `0`,
		double	mSpacing = `0`
	)		const

overridevirtual

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

hSpacing	Horizontal spacing of the grid (x axis). 0 to disable.
vSpacing	Vertical spacing of the grid (y axis). 0 to disable.
dSpacing	Depth spacing of the grid (z axis). 0 (default) to disable.
mSpacing	Custom dimension spacing of the grid (m axis). 0 (default) to disable.

Implements QgsAbstractGeometry.

Definition at line 627 of file qgscircularstring.cpp.

◆ splitCurveAtVertex()

std::tuple< std::unique_ptr< QgsCurve >, std::unique_ptr< QgsCurve > > QgsCircularString::splitCurveAtVertex ( int index ) const

finalvirtual

Splits the curve at the specified vertex index, returning two curves which represent the portion of the curve up to an including the vertex at index, and the portion of the curve from the vertex at index (inclusive) to the end of the curve.

Note: The vertex index must correspond to a segment vertex, not a curve vertex.; Not available in Python bindings.

Since: QGIS 3.20

Implements QgsCurve.

Definition at line 923 of file qgscircularstring.cpp.

◆ startPoint()

QgsPoint QgsCircularString::startPoint ( ) const

overridevirtual

Returns the starting point of the curve.

See also: endPoint

Implements QgsCurve.

Definition at line 594 of file qgscircularstring.cpp.

◆ sumUpArea()

void QgsCircularString::sumUpArea ( double & sum ) const

overridevirtual

Sums up the area of the curve by iterating over the vertices (shoelace formula).

Implements QgsCurve.

Definition at line 1358 of file qgscircularstring.cpp.

◆ swapXy()

void QgsCircularString::swapXy ( )

overridevirtual

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

Implements QgsAbstractGeometry.

Definition at line 1863 of file qgscircularstring.cpp.

◆ transform() [1/3]

void QgsCircularString::transform	(	const QgsCoordinateTransform &	ct,
		Qgis::TransformDirection	d = `Qgis::TransformDirection::Forward`,
		bool	transformZ = `false`
	)

overridevirtual

Transforms the geometry using a coordinate transform.

Parameters

ct	coordinate transform
d	transformation direction
transformZ	set 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.

Implements QgsAbstractGeometry.

Definition at line 1121 of file qgscircularstring.cpp.

◆ transform() [2/3]

void QgsCircularString::transform	(	const QTransform &	t,
		double	zTranslate = `0.0`,
		double	zScale = `1.0`,
		double	mTranslate = `0.0`,
		double	mScale = `1.0`
	)

overridevirtual

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.

Implements QgsAbstractGeometry.

Definition at line 1145 of file qgscircularstring.cpp.

◆ transform() [3/3]

bool QgsCircularString::transform	(	QgsAbstractGeometryTransformer *	transformer,
		QgsFeedback *	feedback = `nullptr`
	)

overridevirtual

Transforms the vertices from the geometry in place, using the specified geometry transformer object.

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

The optional feedback argument can be used to cancel the transformation before it completes. If this is done, the geometry will be left in a semi-transformed state.

Returns: true if the geometry was successfully transformed.

Since: QGIS 3.18

Implements QgsAbstractGeometry.

Definition at line 805 of file qgscircularstring.cpp.

◆ transformVertices()

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

overridevirtual

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 from QgsAbstractGeometry.

Definition at line 895 of file qgscircularstring.cpp.

◆ vertexAngle()

double QgsCircularString::vertexAngle ( QgsVertexId vertex ) const

overridevirtual

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

vertex the vertex id

Returns: rotation in radians, clockwise from north

Implements QgsAbstractGeometry.

Definition at line 1514 of file qgscircularstring.cpp.

◆ wkbSize()

int QgsCircularString::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

Implements QgsAbstractGeometry.

Definition at line 498 of file qgscircularstring.cpp.

◆ xAt()

double QgsCircularString::xAt ( int index ) const

overridevirtual

Returns the x-coordinate of the specified node in the line string.

Parameters

index index of node, where the first node in the line is 0

Returns: x-coordinate of node, or 0.0 if index is out of bounds

Implements QgsCurve.

Definition at line 773 of file qgscircularstring.cpp.

◆ yAt()

double QgsCircularString::yAt ( int index ) const

overridevirtual

Returns the y-coordinate of the specified node in the line string.

Parameters

index index of node, where the first node in the line is 0

Returns: y-coordinate of node, or 0.0 if index is out of bounds

Implements QgsCurve.

Definition at line 781 of file qgscircularstring.cpp.

◆ zAt()

double QgsCircularString::zAt ( int index ) const

overridevirtual

Returns the z-coordinate of the specified node in the line string.

Parameters

index index of node, where the first node in the line is 0

Returns: z-coordinate of node, or 0.0 if index is out of bounds

Since: QGIS 3.28

Implements QgsCurve.

Definition at line 789 of file qgscircularstring.cpp.

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

/build/qgis-3.36.0+99sid/src/core/geometry/qgscircularstring.h
/build/qgis-3.36.0+99sid/src/core/geometry/qgscircularstring.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QgsCircularString() [1/3]

◆ QgsCircularString() [2/3]

◆ QgsCircularString() [3/3]

Member Function Documentation

◆ addMValue()

◆ addToPainterPath()

◆ addZValue()

◆ append()

◆ asGml2()

◆ asGml3()

◆ asJsonObject()

◆ asWkb()

◆ asWkt()

◆ calculateBoundingBox3D()

◆ cast()

◆ clear()

◆ clone()

◆ closestSegment()

◆ compareToSameClass()

◆ createEmptyWithSameType()

◆ curveSubstring()

◆ curveToLine()

◆ deleteVertex()

◆ dimension()

◆ draw()

◆ drawAsPolygon()

◆ dropMValue()

◆ dropZValue()

◆ endPoint()

◆ equals()

◆ filterVertices()

◆ fromTwoPointsAndCenter()

◆ fromWkb()

◆ fromWkt()

◆ fuzzyDistanceEqual()

◆ fuzzyEqual()

◆ geometryType()

◆ hasCurvedSegments()

◆ indexOf()

◆ insertVertex()

◆ interpolatePoint()

◆ isEmpty()

◆ isValid()

◆ length()

◆ mAt()

◆ moveVertex()

◆ numPoints()

◆ pointAt()

◆ pointN()

◆ points()

◆ removeDuplicateNodes()

◆ reversed()

◆ scroll()

◆ segmentLength()

◆ setPoints()

◆ snappedToGrid()

◆ splitCurveAtVertex()

◆ startPoint()

◆ sumUpArea()

◆ swapXy()

◆ transform() [1/3]

◆ transform() [2/3]

◆ transform() [3/3]

◆ transformVertices()

◆ vertexAngle()

◆ wkbSize()

◆ xAt()

◆ yAt()

◆ zAt()