Line string geometry type, with support for z-dimension and m-values. More...

#include <qgslinestring.h>

Inheritance diagram for QgsLineString:

Public Member Functions
	QgsLineString ()

	QgsLineString (const QgsLineSegment2D &segment)
	Construct a linestring from a single 2d line segment. More...

	QgsLineString (const QgsPoint &p1, const QgsPoint &p2)
	Constructs a linestring with a single segment from p1 to p2. More...

	QgsLineString (const QVector< double > &x, const QVector< double > &y, const QVector< double > &z=QVector< double >(), const QVector< double > &m=QVector< double >(), bool is25DType=false)
	Construct a linestring from arrays of coordinates. More...

	QgsLineString (const QVector< QgsPoint > &points)
	Construct a linestring from a vector of points. More...

	QgsLineString (const QVector< QgsPointXY > &points)
	Construct a linestring from list of points. More...

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

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

void	addVertex (const QgsPoint &pt)
	Adds a new vertex to the end of the line string. More...

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

void	append (const QgsLineString *line)
	Appends the contents of another line string to the end of this line string. More...

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. More...

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. More...

json	asJsonObject (int precision=17) const override
	Returns a json object representation of the geometry. More...

QString	asKml (int precision=17) const override
	Returns a KML representation of the geometry. More...

QPolygonF	asQPolygonF () const override
	Returns a QPolygonF representing the points. More...

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

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

const QgsLineString *	cast (const QgsAbstractGeometry *geom) const
	Cast the geom to a QgsLineString. More...

QgsPoint	centroid () const override
	Returns the centroid of the geometry. More...

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

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

void	close ()
	Closes the line string by appending the first point to the end of the line, if it is not already closed. More...

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. More...

bool	convertTo (QgsWkbTypes::Type type) override
	Converts the geometry to a specified type. More...

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

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

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. More...

bool	deleteVertex (QgsVertexId position) override
	Deletes a vertex within the geometry. More...

int	dimension () const override
	Returns the inherent dimension of the geometry. More...

void	draw (QPainter &p) const override
	Draws the geometry using the specified QPainter. More...

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

bool	dropMValue () override
	Drops any measure values which exist in the geometry. More...

bool	dropZValue () override
	Drops any z-dimensions which exist in the geometry. More...

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

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

void	extend (double startDistance, double endDistance)
	Extends the line geometry by extrapolating out the start or end of the line by a specified distance. More...

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. More...

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

bool	fromWkt (const QString &wkt) override
	Sets the geometry from a WKT string. More...

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

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

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

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

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

double	length3D () const
	Returns the length in 3D world of the line string. More...

double	mAt (int index) const
	Returns the m value of the specified node in the line string. More...

const double *	mData () const
	Returns a const pointer to the m vertex data, or `nullptr` if the linestring does not have m values. More...

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

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

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

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

QgsPoint	pointN (int i) const
	Returns the specified point from inside the line string. More...

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

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. More...

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

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

void	setMAt (int index, double m)
	Sets the m value of the specified node in the line string. More...

void	setPoints (const QgsPointSequence &points)
	Resets the line string to match the specified list of points. More...

void	setXAt (int index, double x)
	Sets the x-coordinate of the specified node in the line string. More...

void	setYAt (int index, double y)
	Sets the y-coordinate of the specified node in the line string. More...

void	setZAt (int index, double z)
	Sets the z-coordinate of the specified node in the line string. More...

QgsLineString *	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. More...

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

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

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

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

void	transform (const QgsCoordinateTransform &ct, QgsCoordinateTransform::TransformDirection d=QgsCoordinateTransform::ForwardTransform, bool transformZ=false) override SIP_THROW(QgsCsException)
	Transforms the geometry using a coordinate transform. More...

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. More...

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. More...

double	vertexAngle (QgsVertexId vertex) const override
	Returns approximate angle at a vertex. More...

void	visitPointsByRegularDistance (double distance, const std::function< bool(double x, double y, double z, double m, double startSegmentX, double startSegmentY, double startSegmentZ, double startSegmentM, double endSegmentX, double endSegmentY, double endSegmentZ, double endSegmentM) > &visitPoint) const
	Visits regular points along the linestring, spaced by distance. More...

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

const double *	xData () const
	Returns a const pointer to the x vertex data. More...

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

const double *	yData () const
	Returns a const pointer to the y vertex data. More...

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

const double *	zData () const
	Returns a const pointer to the z vertex data, or `nullptr` if the linestring does not have z values. More...

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

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

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

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

const QgsCurve *	cast (const QgsAbstractGeometry *geom) const
	Cast the geom to a QgsCurve. More...

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

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

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

bool	isValid (QString &error, int flags=0) const override
	Checks validity of the geometry, and returns `true` if the geometry is valid. More...

bool	nextVertex (QgsVertexId &id, QgsPoint &vertex) const override
	Returns next vertex id and coordinates. More...

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

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

Orientation	orientation () const
	Returns the curve's orientation, e.g. More...

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

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

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

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

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

QgsPoint	vertexAt (QgsVertexId id) const override
	Returns the point corresponding to a specified vertex id. More...

int	vertexCount (int part=0, int ring=0) const override
	Returns the number of vertices of which this geometry is built. More...

int	vertexNumberFromVertexId (QgsVertexId id) const override
	Returns the vertex number corresponding to a vertex id. More...

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

	QgsAbstractGeometry (const QgsAbstractGeometry &geom)

virtual	~QgsAbstractGeometry ()=default

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

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

virtual QByteArray	asWkb (WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const =0
	Returns a WKB representation of the geometry. 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	hasCurvedSegments () const
	Returns `true` if the geometry contains curved segments. More...

bool	is3D () const
	Returns `true` if the geometry is 3D and contains a z-value. More...

bool	isMeasure () const
	Returns `true` if the geometry contains m values. More...

QgsAbstractGeometry &	operator= (const QgsAbstractGeometry &geom)

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...

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...

Static Public Member Functions
static QgsLineString *	fromBezierCurve (const QgsPoint &start, const QgsPoint &controlPoint1, const QgsPoint &controlPoint2, const QgsPoint &end, int segments=30)
	Returns a new linestring created by segmentizing the bezier curve between start and end, with the specified control points. More...

static QgsLineString *	fromQPolygonF (const QPolygonF &polygon)
	Returns a new linestring from a QPolygonF polygon input. More...

Protected Member Functions
QgsRectangle	calculateBoundingBox () const override
	Default calculator for the minimal bounding box for the geometry. More...

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. More...

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

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

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. More...

Protected Member Functions inherited from QgsAbstractGeometry
virtual QgsAbstractGeometry *	childGeometry (int index) const
	Returns pointer to child geometry (for geometries with child geometries - i.e. 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...

Friends
class	QgsPolygon

class	QgsTriangle

Additional Inherited Members
Public Types inherited from QgsCurve
enum	Orientation { Clockwise, CounterClockwise }
	Curve orientation. More...

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 }
	WKB export flags. More...

Protected Attributes inherited from QgsAbstractGeometry
QgsWkbTypes::Type	mWkbType = QgsWkbTypes::Unknown

Detailed Description

Line string geometry type, with support for z-dimension and m-values.

Since: QGIS 2.10

Definition at line 43 of file qgslinestring.h.

Constructor & Destructor Documentation

◆ QgsLineString() [1/6]

QgsLineString::QgsLineString ( )

Definition at line 42 of file qgslinestring.cpp.

◆ QgsLineString() [2/6]

QgsLineString::QgsLineString ( const QVector< QgsPoint > & points )

Construct a linestring from a vector of points.

Z and M type will be set based on the type of the first point in the vector.

Since: QGIS 3.0

Definition at line 47 of file qgslinestring.cpp.

◆ QgsLineString() [3/6]

QgsLineString::QgsLineString	(	const QVector< double > &	x,
		const QVector< double > &	y,
		const QVector< double > &	z = `QVector<double>()`,
		const QVector< double > &	m = `QVector<double>()`,
		bool	is25DType = `false`
	)

Construct a linestring from arrays of coordinates.

If the z or m arrays are non-empty then the resultant linestring will have z and m types accordingly. This constructor is more efficient then calling setPoints() or repeatedly calling addVertex()

If the z vector is filled, then the geometry type will either be a LineStringZ(M) or LineString25D depending on the is25DType argument. If is25DType is true (and the m vector is unfilled) then the created Linestring will be a LineString25D type. Otherwise, the LineString will be LineStringZ (or LineStringZM) type.

Since: QGIS 3.0

Definition at line 84 of file qgslinestring.cpp.

◆ QgsLineString() [4/6]

QgsLineString::QgsLineString	(	const QgsPoint &	p1,
		const QgsPoint &	p2
	)

Constructs a linestring with a single segment from p1 to p2.

Since: QGIS 3.2

Definition at line 130 of file qgslinestring.cpp.

◆ QgsLineString() [5/6]

QgsLineString::QgsLineString ( const QVector< QgsPointXY > & points )

Construct a linestring from list of points.

This constructor is more efficient then calling setPoints() or repeatedly calling addVertex()

Since: QGIS 3.0

Definition at line 155 of file qgslinestring.cpp.

◆ QgsLineString() [6/6]

QgsLineString::QgsLineString ( const QgsLineSegment2D & segment )

explicit

Construct a linestring from a single 2d line segment.

Since: QGIS 3.2

Definition at line 167 of file qgslinestring.cpp.

Member Function Documentation

◆ addMValue()

bool QgsLineString::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()

Since: QGIS 2.12

Implements QgsAbstractGeometry.

Definition at line 1580 of file qgslinestring.cpp.

◆ addToPainterPath()

void QgsLineString::addToPainterPath ( QPainterPath & path ) const

overridevirtual

Adds a curve to a painter path.

Implements QgsCurve.

Definition at line 1074 of file qgslinestring.cpp.

◆ addVertex()

void QgsLineString::addVertex ( const QgsPoint & pt )

Adds a new vertex to the end of the line string.

Parameters

pt	vertex to add

Definition at line 1290 of file qgslinestring.cpp.

◆ addZValue()

bool QgsLineString::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()

Since: QGIS 2.12

Implements QgsAbstractGeometry.

Definition at line 1556 of file qgslinestring.cpp.

◆ append()

void QgsLineString::append ( const QgsLineString * line )

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

Parameters

line	line to append. Ownership is not transferred.

Definition at line 815 of file qgslinestring.cpp.

◆ asGml2()

QDomElement QgsLineString::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 481 of file qgslinestring.cpp.

◆ asGml3()

QDomElement QgsLineString::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 496 of file qgslinestring.cpp.

◆ asJsonObject()

json QgsLineString::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 510 of file qgslinestring.cpp.

◆ asKml()

QString QgsLineString::asKml ( int precision = 17 ) const

overridevirtual

Returns a KML representation of the geometry.

Since: QGIS 3.12

Reimplemented from QgsCurve.

Definition at line 521 of file qgslinestring.cpp.

◆ asQPolygonF()

QPolygonF QgsLineString::asQPolygonF ( ) const

overridevirtual

Returns a QPolygonF representing the points.

Reimplemented from QgsCurve.

Definition at line 366 of file qgslinestring.cpp.

◆ asWkb()

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

override

Definition at line 444 of file qgslinestring.cpp.

◆ asWkt()

QString QgsLineString::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 466 of file qgslinestring.cpp.

◆ calculateBoundingBox()

QgsRectangle QgsLineString::calculateBoundingBox ( ) const

overrideprotectedvirtual

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 from QgsAbstractGeometry.

Definition at line 398 of file qgslinestring.cpp.

◆ cast()

const QgsLineString* QgsLineString::cast ( const QgsAbstractGeometry * geom ) const

inline

Cast the geom to a QgsLineString.

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

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

Since: QGIS 3.0

Definition at line 666 of file qgslinestring.h.

◆ centroid()

QgsPoint QgsLineString::centroid ( ) const

overridevirtual

Returns the centroid of the geometry.

Reimplemented from QgsAbstractGeometry.

Definition at line 1398 of file qgslinestring.cpp.

◆ clear()

void QgsLineString::clear ( )

overridevirtual

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

Implements QgsAbstractGeometry.

Definition at line 298 of file qgslinestring.cpp.

◆ clone()

QgsLineString * QgsLineString::clone ( ) const

overridevirtual

Clones the geometry by performing a deep copy.

Implements QgsCurve.

Definition at line 293 of file qgslinestring.cpp.

◆ close()

void QgsLineString::close ( )

Closes the line string by appending the first point to the end of the line, if it is not already closed.

Definition at line 1488 of file qgslinestring.cpp.

◆ closestSegment()

double QgsLineString::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 1310 of file qgslinestring.cpp.

◆ convertTo()

bool QgsLineString::convertTo ( QgsWkbTypes::Type type )

overridevirtual

Converts the geometry to a specified type.

Returns: true if conversion was successful

Since: QGIS 2.14

Reimplemented from QgsAbstractGeometry.

Definition at line 1639 of file qgslinestring.cpp.

◆ createEmptyWithSameType()

QgsLineString * QgsLineString::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()

Since: 3.0

Implements QgsAbstractGeometry.

Definition at line 1131 of file qgslinestring.cpp.

◆ curveSubstring()

QgsLineString * QgsLineString::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 973 of file qgslinestring.cpp.

◆ curveToLine()

QgsLineString * QgsLineString::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

Implements QgsCurve.

Definition at line 643 of file qgslinestring.cpp.

◆ deleteVertex()

bool QgsLineString::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 1257 of file qgslinestring.cpp.

◆ dimension()

int QgsLineString::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 1143 of file qgslinestring.cpp.

◆ draw()

void QgsLineString::draw ( QPainter & p ) const

overridevirtual

Draws the geometry using the specified QPainter.

Parameters

p	destination QPainter

Implements QgsAbstractGeometry.

Definition at line 1069 of file qgslinestring.cpp.

◆ drawAsPolygon()

void QgsLineString::drawAsPolygon ( QPainter & p ) const

overridevirtual

Draws the curve as a polygon on the specified QPainter.

Parameters

p	destination QPainter

Implements QgsCurve.

Definition at line 1093 of file qgslinestring.cpp.

◆ dropMValue()

bool QgsLineString::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()

Since: QGIS 2.14

Implements QgsAbstractGeometry.

Definition at line 1622 of file qgslinestring.cpp.

◆ dropZValue()

bool QgsLineString::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()

Since: QGIS 2.14

Implements QgsAbstractGeometry.

Definition at line 1611 of file qgslinestring.cpp.

◆ endPoint()

QgsPoint QgsLineString::endPoint ( ) const

overridevirtual

Returns the end point of the curve.

See also: startPoint

Implements QgsCurve.

Definition at line 628 of file qgslinestring.cpp.

◆ equals()

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

overridevirtual

Checks whether this curve exactly equals another curve.

Since: QGIS 3.0

Implements QgsCurve.

Definition at line 265 of file qgslinestring.cpp.

◆ extend()

void QgsLineString::extend	(	double	startDistance,
		double	endDistance
	)

Extends the line geometry by extrapolating out the start or end of the line by a specified distance.

Lines are extended using the bearing of the first or last segment in the line.

Since: QGIS 3.0

Definition at line 1105 of file qgslinestring.cpp.

◆ filterVertices()

void QgsLineString::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 1659 of file qgslinestring.cpp.

◆ fromBezierCurve()

QgsLineString * QgsLineString::fromBezierCurve	(	const QgsPoint &	start,
		const QgsPoint &	controlPoint1,
		const QgsPoint &	controlPoint2,
		const QgsPoint &	end,
		int	segments = `30`
	)

static

Returns a new linestring created by segmentizing the bezier curve between start and end, with the specified control points.

The segments parameter controls how many line segments will be present in the returned linestring.

Any z or m values present in the input coordinates will be interpolated along with the x and y values.

Since: QGIS 3.10

Definition at line 184 of file qgslinestring.cpp.

◆ fromQPolygonF()

QgsLineString * QgsLineString::fromQPolygonF ( const QPolygonF & polygon )

static

Returns a new linestring from a QPolygonF polygon input.

Since: QGIS 3.10

Definition at line 245 of file qgslinestring.cpp.

◆ fromWkb()

bool QgsLineString::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 381 of file qgslinestring.cpp.

◆ fromWkt()

bool QgsLineString::fromWkt ( const QString & wkt )

overridevirtual

Sets the geometry from a WKT string.

See also: fromWkb

Implements QgsAbstractGeometry.

Definition at line 427 of file qgslinestring.cpp.

◆ geometryType()

QString QgsLineString::geometryType ( ) const

overridevirtual

Returns a unique string representing the geometry type.

See also: wkbType; wktTypeStr

Implements QgsAbstractGeometry.

Definition at line 1138 of file qgslinestring.cpp.

◆ insertVertex()

bool QgsLineString::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 1211 of file qgslinestring.cpp.

◆ interpolatePoint()

QgsPoint * QgsLineString::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 953 of file qgslinestring.cpp.

◆ isEmpty()

bool QgsLineString::isEmpty ( ) const

overridevirtual

Returns true if the geometry is empty.

Reimplemented from QgsAbstractGeometry.

Definition at line 308 of file qgslinestring.cpp.

◆ length()

double QgsLineString::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 qgslinestring.cpp.

◆ length3D()

double QgsLineString::length3D ( ) const

Returns the length in 3D world of the line string.

If it is not a 3D line string, return its 2D length.

See also: length()

Since: QGIS 3.10

Definition at line 597 of file qgslinestring.cpp.

◆ mAt()

double QgsLineString::mAt ( int index ) const

inline

Returns the m value of the specified node in the line string.

Parameters

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

Returns: m value of node, or nan if index is out of bounds or the line does not have m values

See also: setMAt()

Definition at line 320 of file qgslinestring.h.

◆ mData()

const double* QgsLineString::mData ( ) const

inline

Returns a const pointer to the m vertex data, or nullptr if the linestring does not have m values.

Note: Not available in Python bindings

See also: xData(); yData()

Since: QGIS 3.2

Definition at line 257 of file qgslinestring.h.

◆ moveVertex()

bool QgsLineString::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 1237 of file qgslinestring.cpp.

◆ nCoordinates()

int QgsLineString::nCoordinates ( ) const

overridevirtual

Returns the number of nodes contained in the geometry.

Reimplemented from QgsAbstractGeometry.

Definition at line 655 of file qgslinestring.cpp.

◆ numPoints()

int QgsLineString::numPoints ( ) const

overridevirtual

Returns the number of points in the curve.

Implements QgsCurve.

Definition at line 650 of file qgslinestring.cpp.

◆ pointAt()

bool QgsLineString::pointAt	(	int	node,
		QgsPoint &	point,
		QgsVertexId::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 1387 of file qgslinestring.cpp.

◆ pointN()

QgsPoint QgsLineString::pointN ( int i ) const

Returns the specified point from inside the line string.

Parameters

i	index of point, starting at 0 for the first point

Definition at line 660 of file qgslinestring.cpp.

◆ points()

void QgsLineString::points ( QgsPointSequence & pt ) const

overridevirtual

Returns a list of points within the curve.

Implements QgsCurve.

Definition at line 745 of file qgslinestring.cpp.

◆ removeDuplicateNodes()

bool QgsLineString::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.

Since: QGIS 3.0

Implements QgsAbstractGeometry.

Definition at line 326 of file qgslinestring.cpp.

◆ reversed()

QgsLineString * QgsLineString::reversed ( ) const

overridevirtual

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

Since: QGIS 2.14

Implements QgsCurve.

Definition at line 877 of file qgslinestring.cpp.

◆ segmentLength()

double QgsLineString::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.

Since: QGIS 3.0

Implements QgsAbstractGeometry.

Definition at line 1540 of file qgslinestring.cpp.

◆ setMAt()

void QgsLineString::setMAt	(	int	index,
		double	m
	)

inline

Sets the m value of the specified node in the line string.

Parameters

index	index of node, where the first node in the line is 0. Corresponding node must already exist in line string, and the line string must have m values.
m	m value of node

See also: mAt()

Definition at line 493 of file qgslinestring.h.

◆ setPoints()

void QgsLineString::setPoints ( const QgsPointSequence & points )

Resets the line string to match the specified list of points.

The line string will inherit the dimensionality of the first point in the list.

Parameters

points new points for line string. If empty, line string will be cleared.

Definition at line 756 of file qgslinestring.cpp.

◆ setXAt()

void QgsLineString::setXAt	(	int	index,
		double	x
	)

Sets 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. Corresponding node must already exist in line string.
x	x-coordinate of node

See also: xAt()

Definition at line 725 of file qgslinestring.cpp.

◆ setYAt()

void QgsLineString::setYAt	(	int	index,
		double	y
	)

Sets 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. Corresponding node must already exist in line string.
y	y-coordinate of node

See also: yAt()

Definition at line 732 of file qgslinestring.cpp.

◆ setZAt()

void QgsLineString::setZAt	(	int	index,
		double	z
	)

inline

Sets 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. Corresponding node must already exist in line string, and the line string must have z-dimension.
z	z-coordinate of node

See also: zAt()

Definition at line 448 of file qgslinestring.h.

◆ snappedToGrid()

QgsLineString * QgsLineString::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.

Since: 3.0

Implements QgsAbstractGeometry.

Definition at line 313 of file qgslinestring.cpp.

◆ startPoint()

QgsPoint QgsLineString::startPoint ( ) const

overridevirtual

Returns the starting point of the curve.

See also: endPoint

Implements QgsCurve.

Definition at line 619 of file qgslinestring.cpp.

◆ sumUpArea()

void QgsLineString::sumUpArea ( double & sum ) const

overridevirtual

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

Implements QgsCurve.

Definition at line 1442 of file qgslinestring.cpp.

◆ swapXy()

void QgsLineString::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 1633 of file qgslinestring.cpp.

◆ toCurveType()

QgsCompoundCurve * QgsLineString::toCurveType ( ) const

overridevirtual

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

Returns: the converted geometry. Caller takes ownership

Reimplemented from QgsCurve.

Definition at line 1098 of file qgslinestring.cpp.

◆ transform() [1/2]

void QgsLineString::transform	(	const QgsCoordinateTransform &	ct,
		QgsCoordinateTransform::TransformDirection	d = `QgsCoordinateTransform::ForwardTransform`,
		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 1154 of file qgslinestring.cpp.

◆ transform() [2/2]

void QgsLineString::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 1176 of file qgslinestring.cpp.

◆ transformVertices()

void QgsLineString::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 1705 of file qgslinestring.cpp.

◆ vertexAngle()

double QgsLineString::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 1497 of file qgslinestring.cpp.

◆ visitPointsByRegularDistance()

void QgsLineString::visitPointsByRegularDistance	(	double	distance,
		const std::function< bool(double x, double y, double z, double m, double startSegmentX, double startSegmentY, double startSegmentZ, double startSegmentM, double endSegmentX, double endSegmentY, double endSegmentZ, double endSegmentM) > &	visitPoint
	)		const

Visits regular points along the linestring, spaced by distance.

The visitPoint function should return false to abort further traversal.

Definition at line 893 of file qgslinestring.cpp.

◆ xAt()

double QgsLineString::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 709 of file qgslinestring.cpp.

◆ xData()

const double* QgsLineString::xData ( ) const

inline

Returns a const pointer to the x vertex data.

Note: Not available in Python bindings

See also: yData()

Since: QGIS 3.2

Definition at line 217 of file qgslinestring.h.

◆ yAt()

double QgsLineString::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 717 of file qgslinestring.cpp.

◆ yData()

const double* QgsLineString::yData ( ) const

inline

Returns a const pointer to the y vertex data.

Note: Not available in Python bindings

See also: xData()

Since: QGIS 3.2

Definition at line 228 of file qgslinestring.h.

◆ zAt()

double QgsLineString::zAt ( int index ) const

inline

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 nan if index is out of bounds or the line does not have a z dimension

See also: setZAt()

Definition at line 274 of file qgslinestring.h.

◆ zData()

const double* QgsLineString::zData ( ) const

inline

Returns a const pointer to the z vertex data, or nullptr if the linestring does not have z values.

Note: Not available in Python bindings

See also: xData(); yData()

Since: QGIS 3.2

Definition at line 241 of file qgslinestring.h.

Friends And Related Function Documentation

◆ QgsPolygon

friend class QgsPolygon

friend

Definition at line 790 of file qgslinestring.h.

◆ QgsTriangle

friend class QgsTriangle

friend

Definition at line 791 of file qgslinestring.h.

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

/build/qgis-3.14.0+99unstable/src/core/geometry/qgslinestring.h
/build/qgis-3.14.0+99unstable/src/core/geometry/qgslinestring.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QgsLineString() [1/6]

◆ QgsLineString() [2/6]

◆ QgsLineString() [3/6]

◆ QgsLineString() [4/6]

◆ QgsLineString() [5/6]

◆ QgsLineString() [6/6]

Member Function Documentation

◆ addMValue()

◆ addToPainterPath()

◆ addVertex()

◆ addZValue()

◆ append()

◆ asGml2()

◆ asGml3()

◆ asJsonObject()

◆ asKml()

◆ asQPolygonF()

◆ asWkb()

◆ asWkt()

◆ calculateBoundingBox()

◆ cast()

◆ centroid()

◆ clear()

◆ clone()

◆ close()

◆ closestSegment()

◆ convertTo()

◆ createEmptyWithSameType()

◆ curveSubstring()

◆ curveToLine()

◆ deleteVertex()

◆ dimension()

◆ draw()

◆ drawAsPolygon()

◆ dropMValue()

◆ dropZValue()

◆ endPoint()

◆ equals()

◆ extend()

◆ filterVertices()

◆ fromBezierCurve()

◆ fromQPolygonF()

◆ fromWkb()

◆ fromWkt()

◆ geometryType()

◆ insertVertex()

◆ interpolatePoint()

◆ isEmpty()

◆ length()

◆ length3D()

◆ mAt()

◆ mData()

◆ moveVertex()

◆ nCoordinates()

◆ numPoints()

◆ pointAt()

◆ pointN()

◆ points()

◆ removeDuplicateNodes()

◆ reversed()

◆ segmentLength()

◆ setMAt()

◆ setPoints()

◆ setXAt()

◆ setYAt()

◆ setZAt()

◆ snappedToGrid()

Example

◆ startPoint()

◆ sumUpArea()

◆ swapXy()

◆ toCurveType()

◆ transform() [1/2]