QGIS API Documentation
3.18.1-Zürich (202f1bf7e5)
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Abstract base class for curved geometry type. More...
#include <qgscurve.h>
Public Types | |
enum | Orientation { Clockwise , CounterClockwise } |
Curve orientation. More... | |
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enum | AxisOrder { XY = 0 , YX } |
Axis order for GML generation. More... | |
enum | SegmentationToleranceType { MaximumAngle = 0 , MaximumDifference } |
Segmentation tolerance as maximum angle or maximum difference between approximation and circle. More... | |
enum | WkbFlag { FlagExportTrianglesAsPolygons = 1 << 0 } |
WKB export flags. More... | |
Public Member Functions | |
QgsCurve ()=default | |
Constructor for QgsCurve. More... | |
virtual void | addToPainterPath (QPainterPath &path) const =0 |
Adds a curve to a painter path. More... | |
void | adjacentVertices (QgsVertexId vertex, QgsVertexId &previousVertex, QgsVertexId &nextVertex) const override |
Returns the vertices adjacent to a specified vertex within a geometry. More... | |
QString | asKml (int precision=17) const override |
Returns a KML representation of the geometry. More... | |
QPainterPath | asQPainterPath () const override |
Returns the geometry represented as a QPainterPath. More... | |
virtual QPolygonF | asQPolygonF () const |
Returns a QPolygonF representing the points. 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... | |
QgsCurve * | clone () const override=0 |
Clones the geometry by performing a deep copy. More... | |
QgsCoordinateSequence | coordinateSequence () const override |
Retrieves the sequence of geometries, rings and nodes. More... | |
virtual QgsCurve * | curveSubstring (double startDistance, double endDistance) const =0 |
Returns a new curve representing a substring of this curve. More... | |
virtual QgsLineString * | curveToLine (double tolerance=M_PI_2/90, SegmentationToleranceType toleranceType=MaximumAngle) const =0 |
Returns a new line string geometry corresponding to a segmentized approximation of the curve. More... | |
virtual void | drawAsPolygon (QPainter &p) const =0 |
Draws the curve as a polygon on the specified QPainter. More... | |
virtual QgsPoint | endPoint () const =0 |
Returns the end point of the curve. More... | |
virtual bool | equals (const QgsCurve &other) const =0 |
Checks whether this curve exactly equals another curve. More... | |
virtual QgsPoint * | interpolatePoint (double distance) const =0 |
Returns an interpolated point on the curve at the specified distance. More... | |
virtual bool | isClosed () const SIP_HOLDGIL |
Returns true if the curve is closed. More... | |
virtual bool | isRing () const SIP_HOLDGIL |
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... | |
virtual int | numPoints () const =0 |
Returns the number of points in the curve. 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... | |
virtual bool | pointAt (int node, QgsPoint &point, QgsVertexId::VertexType &type) const =0 |
Returns the point and vertex id of a point within the curve. More... | |
virtual void | points (QgsPointSequence &pt) const =0 |
Returns a list of points within the curve. More... | |
virtual QgsCurve * | reversed () const =0 |
Returns a reversed copy of the curve, where the direction of the curve has been flipped. 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... | |
virtual QgsPoint | startPoint () const =0 |
Returns the starting point of the curve. More... | |
double | straightDistance2d () const |
Returns the straight distance of the curve, i.e. More... | |
virtual void | sumUpArea (double &sum) const =0 |
Sums up the area of the curve by iterating over the vertices (shoelace formula). More... | |
QgsCurve * | toCurveType () const override |
Returns the geometry converted to the more generic curve type. 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... | |
virtual double | xAt (int index) const =0 |
Returns the x-coordinate of the specified node in the line string. More... | |
virtual double | yAt (int index) const =0 |
Returns the y-coordinate of the specified node in the line string. More... | |
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QgsAbstractGeometry ()=default | |
Constructor for QgsAbstractGeometry. More... | |
QgsAbstractGeometry (const QgsAbstractGeometry &geom) | |
virtual | ~QgsAbstractGeometry ()=default |
virtual bool | addMValue (double mValue=0)=0 |
Adds a measure to the geometry, initialized to a preset value. More... | |
virtual bool | addZValue (double zValue=0)=0 |
Adds a z-dimension to the geometry, initialized to a preset value. More... | |
virtual double | area () const |
Returns the planar, 2-dimensional area of the geometry. More... | |
virtual QDomElement | asGml2 (QDomDocument &doc, int precision=17, const QString &ns="gml", AxisOrder axisOrder=QgsAbstractGeometry::AxisOrder::XY) const =0 |
Returns a GML2 representation of the geometry. More... | |
virtual QDomElement | asGml3 (QDomDocument &doc, int precision=17, const QString &ns="gml", AxisOrder axisOrder=QgsAbstractGeometry::AxisOrder::XY) const =0 |
Returns a GML3 representation of the geometry. More... | |
QString | asJson (int precision=17) |
Returns a GeoJSON representation of the geometry as a QString. More... | |
virtual json | asJsonObject (int precision=17) const |
Returns a json object representation of the geometry. More... | |
virtual QByteArray | asWkb (WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const =0 |
Returns a WKB representation of the geometry. More... | |
virtual QString | asWkt (int precision=17) const =0 |
Returns a WKT representation of the geometry. More... | |
virtual QgsPoint | centroid () const |
Returns the centroid of the geometry. More... | |
virtual void | clear ()=0 |
Clears the geometry, ie reset it to a null geometry. More... | |
virtual double | closestSegment (const QgsPoint &pt, QgsPoint &segmentPt, QgsVertexId &vertexAfter, int *leftOf=nullptr, double epsilon=4 *std::numeric_limits< double >::epsilon()) const =0 |
Searches for the closest segment of the geometry to a given point. More... | |
const_part_iterator | const_parts_begin () const |
Returns STL-style iterator pointing to the const first part of the geometry. More... | |
const_part_iterator | const_parts_end () const |
Returns STL-style iterator pointing to the imaginary const part after the last part of the geometry. More... | |
virtual bool | convertTo (QgsWkbTypes::Type type) |
Converts the geometry to a specified type. More... | |
virtual QgsAbstractGeometry * | createEmptyWithSameType () const =0 |
Creates a new geometry with the same class and same WKB type as the original and transfers ownership. More... | |
virtual bool | deleteVertex (QgsVertexId position)=0 |
Deletes a vertex within the geometry. More... | |
virtual int | dimension () const =0 |
Returns the inherent dimension of the geometry. More... | |
virtual void | draw (QPainter &p) const =0 |
Draws the geometry using the specified QPainter. More... | |
virtual bool | dropMValue ()=0 |
Drops any measure values which exist in the geometry. More... | |
virtual bool | dropZValue ()=0 |
Drops any z-dimensions which exist in the geometry. More... | |
virtual void | filterVertices (const std::function< bool(const QgsPoint &) > &filter) |
Filters the vertices from the geometry in place, removing any which do not return true for the filter function check. More... | |
virtual bool | fromWkb (QgsConstWkbPtr &wkb)=0 |
Sets the geometry from a WKB string. More... | |
virtual bool | fromWkt (const QString &wkt)=0 |
Sets the geometry from a WKT string. More... | |
virtual QString | geometryType () const =0 |
Returns a unique string representing the geometry type. More... | |
virtual bool | hasCurvedSegments () const |
Returns true if the geometry contains curved segments. More... | |
virtual bool | insertVertex (QgsVertexId position, const QgsPoint &vertex)=0 |
Inserts a vertex into the geometry. More... | |
bool | is3D () const SIP_HOLDGIL |
Returns true if the geometry is 3D and contains a z-value. More... | |
virtual bool | isEmpty () const |
Returns true if the geometry is empty. More... | |
bool | isMeasure () const SIP_HOLDGIL |
Returns true if the geometry contains m values. More... | |
virtual double | length () const |
Returns the planar, 2-dimensional length of the geometry. More... | |
virtual bool | moveVertex (QgsVertexId position, const QgsPoint &newPos)=0 |
Moves a vertex within the geometry. More... | |
virtual int | nCoordinates () const |
Returns the number of nodes contained in the geometry. More... | |
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... | |
virtual bool | removeDuplicateNodes (double epsilon=4 *std::numeric_limits< double >::epsilon(), bool useZValues=false)=0 |
Removes duplicate nodes from the geometry, wherever removing the nodes does not result in a degenerate geometry. More... | |
virtual double | segmentLength (QgsVertexId startVertex) const =0 |
Returns the length of the segment of the geometry which begins at startVertex. More... | |
virtual QgsAbstractGeometry * | snappedToGrid (double hSpacing, double vSpacing, double dSpacing=0, double mSpacing=0) const =0 |
Makes a new geometry with all the points or vertices snapped to the closest point of the grid. More... | |
virtual void | swapXy ()=0 |
Swaps the x and y coordinates from the geometry. More... | |
virtual void | transform (const QgsCoordinateTransform &ct, QgsCoordinateTransform::TransformDirection d=QgsCoordinateTransform::ForwardTransform, bool transformZ=false) SIP_THROW(QgsCsException)=0 |
Transforms the geometry using a coordinate transform. More... | |
virtual void | transform (const QTransform &t, double zTranslate=0.0, double zScale=1.0, double mTranslate=0.0, double mScale=1.0)=0 |
Transforms the x and y components of the geometry using a QTransform object t. More... | |
virtual bool | transform (QgsAbstractGeometryTransformer *transformer, QgsFeedback *feedback=nullptr)=0 |
Transforms the vertices from the geometry in place, using the specified geometry transformer object. More... | |
virtual void | transformVertices (const std::function< QgsPoint(const QgsPoint &) > &transform) |
Transforms the vertices from the geometry in place, applying the transform function to every vertex. More... | |
virtual double | vertexAngle (QgsVertexId vertex) const =0 |
Returns approximate angle at a vertex. More... | |
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... | |
virtual int | wkbSize (QgsAbstractGeometry::WkbFlags flags=QgsAbstractGeometry::WkbFlags()) const =0 |
Returns the length of the QByteArray returned by asWkb() More... | |
QgsWkbTypes::Type | wkbType () const SIP_HOLDGIL |
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 const QgsCurve * | cast (const QgsAbstractGeometry *geom) |
Cast the geom to a QgsCurve. More... | |
Protected Member Functions | |
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... | |
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virtual QgsRectangle | calculateBoundingBox () const |
Default calculator for the minimal bounding box for the geometry. More... | |
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... | |
Additional Inherited Members | |
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QgsWkbTypes::Type | mWkbType = QgsWkbTypes::Unknown |
Abstract base class for curved geometry type.
Definition at line 35 of file qgscurve.h.
Curve orientation.
Enumerator | |
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Clockwise | Clockwise orientation. |
CounterClockwise | Counter-clockwise orientation. |
Definition at line 238 of file qgscurve.h.
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default |
Constructor for QgsCurve.
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pure virtual |
Adds a curve to a painter path.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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overridevirtual |
Returns the vertices adjacent to a specified vertex within a geometry.
Implements QgsAbstractGeometry.
Definition at line 103 of file qgscurve.cpp.
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overridevirtual |
Returns a KML representation of the geometry.
Implements QgsAbstractGeometry.
Reimplemented in QgsLineString.
Definition at line 155 of file qgscurve.cpp.
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overridevirtual |
Returns the geometry represented as a QPainterPath.
Implements QgsAbstractGeometry.
Definition at line 61 of file qgscurve.cpp.
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virtual |
Returns a QPolygonF representing the points.
Reimplemented in QgsLineString.
Definition at line 230 of file qgscurve.cpp.
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overridevirtual |
Returns the closure of the combinatorial boundary of the geometry (ie the topological boundary of the geometry).
For instance, a polygon geometry will have a boundary consisting of the linestrings for each ring in the polygon.
nullptr
for some geometry types. Implements QgsAbstractGeometry.
Definition at line 140 of file qgscurve.cpp.
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overridevirtual |
Returns the minimal bounding box for the geometry.
Implements QgsAbstractGeometry.
Definition at line 202 of file qgscurve.cpp.
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inlinestatic |
Cast the geom to a QgsCurve.
Should be used by qgsgeometry_cast<QgsCurve *>( geometry ).
Definition at line 262 of file qgscurve.h.
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overrideprotectedvirtual |
Returns number of child geometries (for geometries with child geometries) or child points (for geometries without child geometries - i.e.
curve / point)
Reimplemented from QgsAbstractGeometry.
Definition at line 265 of file qgscurve.cpp.
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overrideprotectedvirtual |
Returns point at index (for geometries without child geometries - i.e.
curve / point)
Reimplemented from QgsAbstractGeometry.
Definition at line 270 of file qgscurve.cpp.
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overrideprotectedvirtual |
Clears any cached parameters associated with the geometry, e.g., bounding boxes.
Reimplemented from QgsAbstractGeometry.
Definition at line 257 of file qgscurve.cpp.
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overridepure virtual |
Clones the geometry by performing a deep copy.
Implements QgsAbstractGeometry.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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overridevirtual |
Retrieves the sequence of geometries, rings and nodes.
Implements QgsAbstractGeometry.
Definition at line 68 of file qgscurve.cpp.
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pure virtual |
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.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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pure virtual |
Returns a new line string geometry corresponding to a segmentized approximation of the curve.
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)
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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pure virtual |
Draws the curve as a polygon on the specified QPainter.
p | destination QPainter |
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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pure virtual |
Returns the end point of the curve.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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pure virtual |
Checks whether this curve exactly equals another curve.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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pure virtual |
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.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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virtual |
Returns true
if the curve is closed.
Definition at line 40 of file qgscurve.cpp.
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virtual |
Returns true
if the curve is a ring.
Definition at line 56 of file qgscurve.cpp.
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overridevirtual |
Checks validity of the geometry, and returns true
if the geometry is valid.
error | will be set to the validity error message |
flags | indicates optional flags which control the type of validity checking performed (corresponding to QgsGeometry::ValidityFlags). |
true
if geometry is validImplements QgsAbstractGeometry.
Reimplemented in QgsLineString.
Definition at line 211 of file qgscurve.cpp.
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overridevirtual |
Returns next vertex id and coordinates.
id | initial value should be the starting vertex id. The next vertex id will be stored in this variable if found. |
vertex | container for found node |
false
if at end Implements QgsAbstractGeometry.
Definition at line 78 of file qgscurve.cpp.
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pure virtual |
Returns the number of points in the curve.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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overridevirtual |
Implements QgsAbstractGeometry.
Definition at line 35 of file qgscurve.cpp.
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overridevirtual |
Implements QgsAbstractGeometry.
Definition at line 26 of file qgscurve.cpp.
QgsCurve::Orientation QgsCurve::orientation | ( | ) | const |
Returns the curve's orientation, e.g.
clockwise or counter-clockwise.
Definition at line 250 of file qgscurve.cpp.
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overridevirtual |
Returns count of parts contained in the geometry.
Implements QgsAbstractGeometry.
Definition at line 184 of file qgscurve.cpp.
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pure virtual |
Returns the point and vertex id of a point within the curve.
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 |
true
if node exists within the curve Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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pure virtual |
Returns a list of points within the curve.
Implemented in QgsCompoundCurve, QgsCircularString, and QgsLineString.
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pure virtual |
Returns a reversed copy of the curve, where the direction of the curve has been flipped.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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overridevirtual |
Returns the number of rings of which this geometry is built.
Implements QgsAbstractGeometry.
Definition at line 178 of file qgscurve.cpp.
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overridevirtual |
Returns a geometry without curves.
Caller takes ownership
tolerance | segmentation tolerance |
toleranceType | maximum segmentation angle or maximum difference between approximation and curve |
Reimplemented from QgsAbstractGeometry.
Definition at line 166 of file qgscurve.cpp.
double QgsCurve::sinuosity | ( | ) | const |
Returns the curve sinuosity, which is the ratio of the curve length() to curve straightDistance2d().
Larger numbers indicate a more "sinuous" curve (i.e. more "bendy"). The minimum value returned of 1.0 indicates a perfectly straight curve.
If a curve isClosed(), it has infinite sinuosity and will return NaN.
Definition at line 241 of file qgscurve.cpp.
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protected |
Helper function for QgsCurve subclasses to snap to grids.
Definition at line 280 of file qgscurve.cpp.
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pure virtual |
Returns the starting point of the curve.
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
double QgsCurve::straightDistance2d | ( | ) | const |
Returns the straight distance of the curve, i.e.
the direct/euclidean distance between the first and last vertex of the curve. (Also known as "as the crow flies" distance).
Definition at line 236 of file qgscurve.cpp.
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pure virtual |
Sums up the area of the curve by iterating over the vertices (shoelace formula).
Implemented in QgsLineString, QgsCompoundCurve, and QgsCircularString.
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overridevirtual |
Returns the geometry converted to the more generic curve type.
E.g. QgsLineString -> QgsCompoundCurve, QgsPolygon -> QgsCurvePolygon, QgsMultiLineString -> QgsMultiCurve, QgsMultiPolygon -> QgsMultiSurface
Implements QgsAbstractGeometry.
Reimplemented in QgsLineString.
Definition at line 197 of file qgscurve.cpp.
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overridevirtual |
Returns the point corresponding to a specified vertex id.
Implements QgsAbstractGeometry.
Definition at line 189 of file qgscurve.cpp.
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overridevirtual |
Returns the number of vertices of which this geometry is built.
Implements QgsAbstractGeometry.
Definition at line 171 of file qgscurve.cpp.
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overridevirtual |
Returns the vertex number corresponding to a vertex id.
The vertex numbers start at 0, so a return value of 0 corresponds to the first vertex.
Returns -1 if a corresponding vertex could not be found.
Implements QgsAbstractGeometry.
Definition at line 131 of file qgscurve.cpp.
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pure virtual |
Returns the x-coordinate of the specified node in the line string.
index | index of node, where the first node in the line is 0 |
Implemented in QgsCompoundCurve, QgsCircularString, and QgsLineString.
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pure virtual |
Returns the y-coordinate of the specified node in the line string.
index | index of node, where the first node in the line is 0 |
Implemented in QgsCompoundCurve, QgsCircularString, and QgsLineString.