QGIS API Documentation
3.0.2-Girona (307d082)
|
Line string geometry type, with support for z-dimension and m-values. More...
#include <qgslinestring.h>
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 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") const override |
Returns a GML2 representation of the geometry. More... | |
QDomElement | asGml3 (QDomDocument &doc, int precision=17, const QString &ns="gml") 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... | |
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 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 *DBL_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 * | 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... | |
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... | |
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 *DBL_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... | |
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 |
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... | |
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... | |
double | yAt (int index) const override |
Returns the y-coordinate of the specified node in the line string. More... | |
double | zAt (int index) const |
Returns the z-coordinate of the specified node in the line string. 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... | |
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... | |
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 | 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... | |
QgsCurve * | segmentize (double tolerance=M_PI_2/90, SegmentationToleranceType toleranceType=MaximumAngle) const override |
Returns a geometry without curves. 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... | |
QgsAbstractGeometry & | operator= (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 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 QgsAbstractGeometry | |
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 |
Line string geometry type, with support for z-dimension and m-values.
Definition at line 41 of file qgslinestring.h.
QgsLineString::QgsLineString | ( | ) |
Definition at line 39 of file qgslinestring.cpp.
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.
Definition at line 44 of file qgslinestring.cpp.
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()
Definition at line 81 of file qgslinestring.cpp.
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()
Definition at line 127 of file qgslinestring.cpp.
|
overridevirtual |
Adds a measure to the geometry, initialized to a preset value.
mValue | initial m-value for all nodes |
Implements QgsAbstractGeometry.
Definition at line 1203 of file qgslinestring.cpp.
|
overridevirtual |
Adds a curve to a painter path.
Implements QgsCurve.
Definition at line 707 of file qgslinestring.cpp.
void QgsLineString::addVertex | ( | const QgsPoint & | pt | ) |
Adds a new vertex to the end of the line string.
pt | vertex to add |
Definition at line 917 of file qgslinestring.cpp.
|
overridevirtual |
Adds a z-dimension to the geometry, initialized to a preset value.
zValue | initial z-value for all nodes |
Implements QgsAbstractGeometry.
Definition at line 1179 of file qgslinestring.cpp.
void QgsLineString::append | ( | const QgsLineString * | line | ) |
Appends the contents of another line string to the end of this line string.
line | line to append. Ownership is not transferred. |
Definition at line 618 of file qgslinestring.cpp.
|
overridevirtual |
Returns a GML2 representation of the geometry.
doc | DOM document |
precision | number of decimal places for coordinates |
ns | XML namespace |
Implements QgsAbstractGeometry.
Definition at line 338 of file qgslinestring.cpp.
|
overridevirtual |
Returns a GML3 representation of the geometry.
doc | DOM document |
precision | number of decimal places for coordinates |
ns | XML namespace |
Implements QgsAbstractGeometry.
Definition at line 353 of file qgslinestring.cpp.
|
overridevirtual |
Returns a GeoJSON representation of the geometry.
precision | number of decimal places for coordinates |
Implements QgsAbstractGeometry.
Definition at line 367 of file qgslinestring.cpp.
|
overridevirtual |
Returns a WKB representation of the geometry.
Implements QgsAbstractGeometry.
Definition at line 307 of file qgslinestring.cpp.
|
overridevirtual |
Returns a WKT representation of the geometry.
precision | number of decimal places for coordinates |
Implements QgsAbstractGeometry.
Definition at line 329 of file qgslinestring.cpp.
|
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 263 of file qgslinestring.cpp.
|
inline |
Cast the geom to a QgsLineString.
Should be used by qgsgeometry_cast<QgsLineString *>( geometry ).
Definition at line 249 of file qgslinestring.h.
|
overridevirtual |
Returns the centroid of the geometry.
Reimplemented from QgsAbstractGeometry.
Definition at line 1025 of file qgslinestring.cpp.
|
overridevirtual |
Clears the geometry, ie reset it to a null geometry.
Implements QgsAbstractGeometry.
Definition at line 172 of file qgslinestring.cpp.
|
overridevirtual |
Clones the geometry by performing a deep copy.
Implements QgsCurve.
Definition at line 167 of file qgslinestring.cpp.
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 1111 of file qgslinestring.cpp.
|
overridevirtual |
Searches for the closest segment of the geometry to a given point.
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 |
Implements QgsAbstractGeometry.
Definition at line 937 of file qgslinestring.cpp.
|
overridevirtual |
Converts the geometry to a specified type.
Reimplemented from QgsAbstractGeometry.
Definition at line 1256 of file qgslinestring.cpp.
|
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.
Implements QgsAbstractGeometry.
Definition at line 764 of file qgslinestring.cpp.
|
overridevirtual |
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 |
Implements QgsCurve.
Definition at line 419 of file qgslinestring.cpp.
|
overridevirtual |
Deletes a vertex within the geometry.
position | vertex id for vertex to delete |
Implements QgsAbstractGeometry.
Definition at line 884 of file qgslinestring.cpp.
|
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 776 of file qgslinestring.cpp.
|
overridevirtual |
Draws the geometry using the specified QPainter.
p | destination QPainter |
Implements QgsAbstractGeometry.
Definition at line 702 of file qgslinestring.cpp.
|
overridevirtual |
Draws the curve as a polygon on the specified QPainter.
p | destination QPainter |
Implements QgsCurve.
Definition at line 726 of file qgslinestring.cpp.
|
overridevirtual |
Drops any measure values which exist in the geometry.
Implements QgsAbstractGeometry.
Definition at line 1245 of file qgslinestring.cpp.
|
overridevirtual |
Drops any z-dimensions which exist in the geometry.
Implements QgsAbstractGeometry.
Definition at line 1234 of file qgslinestring.cpp.
|
overridevirtual |
Returns the end point of the curve.
Implements QgsCurve.
Definition at line 404 of file qgslinestring.cpp.
|
overridevirtual |
Checks whether this curve exactly equals another curve.
Implements QgsCurve.
Definition at line 139 of file qgslinestring.cpp.
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.
Definition at line 738 of file qgslinestring.cpp.
|
overridevirtual |
Sets the geometry from a WKB string.
After successful read the wkb argument will be at the position where the reading has stopped.
Implements QgsAbstractGeometry.
Definition at line 240 of file qgslinestring.cpp.
|
overridevirtual |
Sets the geometry from a WKT string.
Implements QgsAbstractGeometry.
Definition at line 293 of file qgslinestring.cpp.
|
overridevirtual |
Returns a unique string representing the geometry type.
Implements QgsAbstractGeometry.
Definition at line 771 of file qgslinestring.cpp.
|
overridevirtual |
Inserts a vertex into the geometry.
position | vertex id for position of inserted vertex |
vertex | vertex to insert |
Implements QgsAbstractGeometry.
Definition at line 838 of file qgslinestring.cpp.
|
overridevirtual |
Returns true if the geometry is empty.
Reimplemented from QgsAbstractGeometry.
Definition at line 182 of file qgslinestring.cpp.
|
overridevirtual |
Returns the length of the geometry.
Reimplemented from QgsAbstractGeometry.
Definition at line 381 of file qgslinestring.cpp.
double QgsLineString::mAt | ( | int | index | ) | const |
Returns the m value of the specified node in the line string.
index | index of node, where the first node in the line is 0 |
nan
if index is out of bounds or the line does not have m values Definition at line 509 of file qgslinestring.cpp.
|
overridevirtual |
Moves a vertex within the geometry.
position | vertex id for vertex to move |
newPos | new position of vertex |
Implements QgsAbstractGeometry.
Definition at line 864 of file qgslinestring.cpp.
|
overridevirtual |
Returns the number of nodes contained in the geometry.
Reimplemented from QgsAbstractGeometry.
Definition at line 431 of file qgslinestring.cpp.
|
overridevirtual |
Returns the number of points in the curve.
Implements QgsCurve.
Definition at line 426 of file qgslinestring.cpp.
|
overridevirtual |
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 |
Implements QgsCurve.
Definition at line 1014 of file qgslinestring.cpp.
QgsPoint QgsLineString::pointN | ( | int | i | ) | const |
Returns the specified point from inside the line string.
i | index of point, starting at 0 for the first point |
Definition at line 436 of file qgslinestring.cpp.
|
overridevirtual |
Returns a list of points within the curve.
Implements QgsCurve.
Definition at line 549 of file qgslinestring.cpp.
|
overridevirtual |
Removes duplicate nodes from the geometry, wherever removing the nodes does not result in a degenerate geometry.
The epsilon parameter specifies the tolerance for coordinates when determining that vertices are identical.
By default, z values are not considered when detecting duplicate nodes. E.g. two nodes with the same x and y coordinate but different z values will still be considered duplicate and one will be removed. If useZValues is true, then the z values are also tested and nodes with the same x and y but different z will be maintained.
Note that duplicate nodes are not tested between different parts of a multipart geometry. E.g. a multipoint geometry with overlapping points will not be changed by this method.
The function will return true if nodes were removed, or false if no duplicate nodes were found.
Implements QgsAbstractGeometry.
Definition at line 200 of file qgslinestring.cpp.
|
overridevirtual |
Returns a reversed copy of the curve, where the direction of the curve has been flipped.
Implements QgsCurve.
Definition at line 680 of file qgslinestring.cpp.
|
overridevirtual |
Returns the length of the segment of the geometry which begins at startVertex.
Implements QgsAbstractGeometry.
Definition at line 1163 of file qgslinestring.cpp.
void QgsLineString::setMAt | ( | int | index, |
double | m | ||
) |
Sets the m value of the specified node in the line string.
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 |
Definition at line 537 of file qgslinestring.cpp.
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.
points | new points for line string. If empty, line string will be cleared. |
Definition at line 559 of file qgslinestring.cpp.
void QgsLineString::setXAt | ( | int | index, |
double | x | ||
) |
Sets the x-coordinate of the specified node in the line string.
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 |
Definition at line 517 of file qgslinestring.cpp.
void QgsLineString::setYAt | ( | int | index, |
double | y | ||
) |
Sets the y-coordinate of the specified node in the line string.
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 |
Definition at line 524 of file qgslinestring.cpp.
void QgsLineString::setZAt | ( | int | index, |
double | z | ||
) |
Sets the z-coordinate of the specified node in the line string.
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 |
Definition at line 531 of file qgslinestring.cpp.
|
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:
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).
hSpacing | Horizontal spacing of the grid (x axis). 0 to disable. |
vSpacing | Vertical spacing of the grid (y axis). 0 to disable. |
dSpacing | Depth spacing of the grid (z axis). 0 (default) to disable. |
mSpacing | Custom dimension spacing of the grid (m axis). 0 (default) to disable. |
Implements QgsAbstractGeometry.
Definition at line 187 of file qgslinestring.cpp.
|
overridevirtual |
Returns the starting point of the curve.
Implements QgsCurve.
Definition at line 395 of file qgslinestring.cpp.
|
overridevirtual |
Sums up the area of the curve by iterating over the vertices (shoelace formula).
Implements QgsCurve.
Definition at line 1069 of file qgslinestring.cpp.
|
overridevirtual |
Returns the geometry converted to the more generic curve type QgsCompoundCurve.
Reimplemented from QgsCurve.
Definition at line 731 of file qgslinestring.cpp.
|
overridevirtual |
Transforms the geometry using a coordinate transform.
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 787 of file qgslinestring.cpp.
|
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 809 of file qgslinestring.cpp.
|
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.
vertex | the vertex id |
Implements QgsAbstractGeometry.
Definition at line 1120 of file qgslinestring.cpp.
|
overridevirtual |
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 |
Implements QgsCurve.
Definition at line 485 of file qgslinestring.cpp.
|
overridevirtual |
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 |
Implements QgsCurve.
Definition at line 493 of file qgslinestring.cpp.
double QgsLineString::zAt | ( | int | index | ) | const |
Returns the z-coordinate of the specified node in the line string.
index | index of node, where the first node in the line is 0 |
nan
if index is out of bounds or the line does not have a z dimension Definition at line 501 of file qgslinestring.cpp.
|
friend |
Definition at line 278 of file qgslinestring.h.
|
friend |
Definition at line 279 of file qgslinestring.h.