QGIS API Documentation  3.3.0-Master (c515a66)
Public Member Functions | Protected Member Functions | Friends | List of all members
QgsLineString Class Reference

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

#include <qgslinestring.h>

Inheritance diagram for QgsLineString:
Inheritance graph
[legend]

Public Member Functions

 QgsLineString ()
 
 QgsLineString (const QVector< QgsPoint > &points)
 Construct a linestring from a vector of points. More...
 
 QgsLineString (const QVector< double > &x, const QVector< double > &y, const QVector< double > &z=QVector< double >(), const QVector< double > &m=QVector< double >())
 Construct a linestring from arrays of coordinates. More...
 
 QgsLineString (const QgsPoint &p1, const QgsPoint &p2)
 Constructs a linestring with a single segment from p1 to p2. More...
 
 QgsLineString (const QVector< QgsPointXY > &points)
 Construct a linestring from list of points. More...
 
 QgsLineString (const QgsLineSegment2D &segment)
 Construct a linestring from a single 2d line segment. 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...
 
QString asJson (int precision=17) const override
 Returns a GeoJSON representation of the geometry. More...
 
QPolygonF asQPolygonF () const override
 Returns a QPolygonF representing the points. More...
 
QByteArray asWkb () const override
 Returns a WKB representation of the geometry. More...
 
QString asWkt (int precision=17) const override
 Returns a WKT representation of the geometry. More...
 
const QgsLineStringcast (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...
 
QgsLineStringclone () 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...
 
QgsLineStringcreateEmptyWithSameType () const override
 Creates a new geometry with the same class and same WKB type as the original and transfers ownership. More...
 
QgsLineStringcurveToLine (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...
 
bool isEmpty () const override
 Returns true if the geometry is empty. More...
 
double length () const override
 Returns the length of the geometry. 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 a 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...
 
QgsLineStringreversed () 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...
 
QgsLineStringsnappedToGrid (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...
 
QgsCompoundCurvetoCurveType () 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...
 
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 a 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...
 
QgsAbstractGeometryboundary () 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 QgsCurvecast (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 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
 
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...
 
QgsCurvesegmentize (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 area 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...
 
QgsAbstractGeometryoperator= (const QgsAbstractGeometry &geom)
 
virtual double perimeter () const
 Returns the perimeter of the geometry. More...
 
QgsVertexIterator vertices () const
 Returns Java-style iterator for traversal of vertices of the geometry. More...
 
vertex_iterator vertices_begin () const
 Returns STL-style iterator pointing to the first vertex of the geometry. More...
 
vertex_iterator vertices_end () const
 Returns STL-style iterator pointing to the imaginary vertex after the last vertex of the geometry. More...
 
QgsWkbTypes::Type wkbType () const
 Returns the WKB type of the geometry. More...
 
QString wktTypeStr () const
 Returns the WKT type string of the geometry. More...
 

Protected Member Functions

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 QgsAbstractGeometrychildGeometry (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 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...
 
- 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 40 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 45 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>() 
)

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()

Since
QGIS 3.0

Definition at line 82 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 128 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 153 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 165 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
mValueinitial m-value for all nodes
Returns
true on success
See also
dropMValue()
addZValue()
Since
QGIS 2.12

Implements QgsAbstractGeometry.

Definition at line 1225 of file qgslinestring.cpp.

◆ addToPainterPath()

void QgsLineString::addToPainterPath ( QPainterPath &  path) const
overridevirtual

Adds a curve to a painter path.

Implements QgsCurve.

Definition at line 725 of file qgslinestring.cpp.

◆ addVertex()

void QgsLineString::addVertex ( const QgsPoint pt)

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

Parameters
ptvertex to add

Definition at line 935 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
zValueinitial z-value for all nodes
Returns
true on success
See also
dropZValue()
addMValue()
Since
QGIS 2.12

Implements QgsAbstractGeometry.

Definition at line 1201 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
lineline to append. Ownership is not transferred.

Definition at line 636 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
docDOM document
precisionnumber of decimal places for coordinates
nsXML namespace
axisOrderAxis order for generated GML
See also
asWkb()
asWkt()
asGml3()
asJson()

Implements QgsAbstractGeometry.

Definition at line 384 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
docDOM document
precisionnumber of decimal places for coordinates
nsXML namespace
axisOrderAxis order for generated GML
See also
asWkb()
asWkt()
asGml2()
asJson()

Implements QgsAbstractGeometry.

Definition at line 399 of file qgslinestring.cpp.

◆ asJson()

QString QgsLineString::asJson ( int  precision = 17) const
overridevirtual

Returns a GeoJSON representation of the geometry.

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

Implements QgsAbstractGeometry.

Definition at line 413 of file qgslinestring.cpp.

◆ asQPolygonF()

QPolygonF QgsLineString::asQPolygonF ( ) const
overridevirtual

Returns a QPolygonF representing the points.

Reimplemented from QgsCurve.

Definition at line 277 of file qgslinestring.cpp.

◆ asWkb()

QByteArray QgsLineString::asWkb ( ) const
overridevirtual

Returns a WKB representation of the geometry.

See also
asWkt
asGml2
asGml3
asJson()
Since
QGIS 3.0

Implements QgsAbstractGeometry.

Definition at line 353 of file qgslinestring.cpp.

◆ asWkt()

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

Returns a WKT representation of the geometry.

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

Implements QgsAbstractGeometry.

Definition at line 375 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 309 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 340 of file qgslinestring.h.

◆ centroid()

QgsPoint QgsLineString::centroid ( ) const
overridevirtual

Returns the centroid of the geometry.

Reimplemented from QgsAbstractGeometry.

Definition at line 1043 of file qgslinestring.cpp.

◆ clear()

void QgsLineString::clear ( )
overridevirtual

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

Implements QgsAbstractGeometry.

Definition at line 209 of file qgslinestring.cpp.

◆ clone()

QgsLineString * QgsLineString::clone ( ) const
overridevirtual

Clones the geometry by performing a deep copy.

Implements QgsCurve.

Definition at line 204 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 1133 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
ptspecifies the point to find closest segment to
segmentPtstorage for the closest point within the geometry
vertexAfterstorage for the ID of the vertex at the end of the closest segment
leftOfindicates whether the point lies on the left side of the geometry (-1 if point is to the left of the geometry, +1 if the point is to the right of the geometry, or 0 for cases where left/right could not be determined, e.g. point exactly on a line) false if point is to right of segment)
epsilonepsilon for segment snapping
Returns
squared distance to closest segment or negative value on error

Implements QgsAbstractGeometry.

Definition at line 955 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 1284 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 782 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
tolerancesegmentation tolerance
toleranceTypemaximum segmentation angle or maximum difference between approximation and curve

Implements QgsCurve.

Definition at line 465 of file qgslinestring.cpp.

◆ deleteVertex()

bool QgsLineString::deleteVertex ( QgsVertexId  position)
overridevirtual

Deletes a vertex within the geometry.

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

Implements QgsAbstractGeometry.

Definition at line 902 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 794 of file qgslinestring.cpp.

◆ draw()

void QgsLineString::draw ( QPainter &  p) const
overridevirtual

Draws the geometry using the specified QPainter.

Parameters
pdestination QPainter

Implements QgsAbstractGeometry.

Definition at line 720 of file qgslinestring.cpp.

◆ drawAsPolygon()

void QgsLineString::drawAsPolygon ( QPainter &  p) const
overridevirtual

Draws the curve as a polygon on the specified QPainter.

Parameters
pdestination QPainter

Implements QgsCurve.

Definition at line 744 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 1267 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 1256 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 450 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 176 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 756 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 1304 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 292 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 339 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 789 of file qgslinestring.cpp.

◆ insertVertex()

bool QgsLineString::insertVertex ( QgsVertexId  position,
const QgsPoint vertex 
)
overridevirtual

Inserts a vertex into the geometry.

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

Implements QgsAbstractGeometry.

Definition at line 856 of file qgslinestring.cpp.

◆ isEmpty()

bool QgsLineString::isEmpty ( ) const
overridevirtual

Returns true if the geometry is empty.

Reimplemented from QgsAbstractGeometry.

Definition at line 219 of file qgslinestring.cpp.

◆ length()

double QgsLineString::length ( ) const
overridevirtual

Returns the length of the geometry.

See also
area()
perimeter()

Reimplemented from QgsAbstractGeometry.

Definition at line 427 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
indexindex 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 175 of file qgslinestring.h.

◆ mData()

const double* QgsLineString::mData ( ) const
inline

Returns a const pointer to the m vertex data, or a 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 145 of file qgslinestring.h.

◆ moveVertex()

bool QgsLineString::moveVertex ( QgsVertexId  position,
const QgsPoint newPos 
)
overridevirtual

Moves a vertex within the geometry.

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

Implements QgsAbstractGeometry.

Definition at line 882 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 477 of file qgslinestring.cpp.

◆ numPoints()

int QgsLineString::numPoints ( ) const
overridevirtual

Returns the number of points in the curve.

Implements QgsCurve.

Definition at line 472 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
nodenode number, where the first node is 0
pointwill be set to point at corresponding node in the curve
typewill be set to the vertex type of the node
Returns
true if node exists within the curve

Implements QgsCurve.

Definition at line 1032 of file qgslinestring.cpp.

◆ pointN()

QgsPoint QgsLineString::pointN ( int  i) const

Returns the specified point from inside the line string.

Parameters
iindex of point, starting at 0 for the first point

Definition at line 482 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 567 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 237 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 698 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.

Since
QGIS 3.0

Implements QgsAbstractGeometry.

Definition at line 1185 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
indexindex 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.
mm value of node
See also
mAt()

Definition at line 221 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
pointsnew points for line string. If empty, line string will be cleared.

Definition at line 577 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
indexindex of node, where the first node in the line is 0. Corresponding node must already exist in line string.
xx-coordinate of node
See also
xAt()

Definition at line 547 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
indexindex of node, where the first node in the line is 0. Corresponding node must already exist in line string.
yy-coordinate of node
See also
yAt()

Definition at line 554 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
indexindex 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.
zz-coordinate of node
See also
zAt()

Definition at line 208 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 a nullptr will be returned. It may generate an invalid geometry (in some corner cases). It can also be thought as rounding the edges and it may be useful for removing errors. Example:

geometry->snappedToGrid(1, 1);

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

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

Implements QgsAbstractGeometry.

Definition at line 224 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 441 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 1087 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 1278 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 749 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
ctcoordinate transform
dtransformation direction
transformZset to true to also transform z coordinates. This requires that the z coordinates in the geometry represent height relative to the vertical datum of the source CRS (generally ellipsoidal heights) and are expressed in its vertical units (generally meters). If false, then z coordinates will not be changed by the transform.

Implements QgsAbstractGeometry.

Definition at line 805 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 827 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 1350 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
vertexthe vertex id
Returns
rotation in radians, clockwise from north

Implements QgsAbstractGeometry.

Definition at line 1142 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
indexindex 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 531 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 105 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
indexindex 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 539 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 116 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
indexindex 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 160 of file qgslinestring.h.

◆ zData()

const double* QgsLineString::zData ( ) const
inline

Returns a const pointer to the z vertex data, or a 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 129 of file qgslinestring.h.

Friends And Related Function Documentation

◆ QgsPolygon

friend class QgsPolygon
friend

Definition at line 381 of file qgslinestring.h.

◆ QgsTriangle

friend class QgsTriangle
friend

Definition at line 382 of file qgslinestring.h.


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