Triangular/Derived Mesh is mesh with vertices in map coordinates. More...

#include <qgstriangularmesh.h>

Classes
class	Changes
	The Changes class is used to make changes of the triangular and to keep traces of this changes If a Changes instance is applied (see QgsTriangularMesh::applyChanges()), these changes can be reversed (see QgsTriangularMesh::reverseChanges()) as long as other changes are not applied. More...

Public Member Functions
	QgsTriangularMesh ()

	~QgsTriangularMesh ()

void	applyChanges (const Changes &changes)
	Applies the changes on the triangular mesh (see Changes)

double	averageTriangleSize () const
	Returns the average size of triangles in map unit.

Q_DECL_DEPRECATED const QVector< QgsMeshVertex > &	centroids () const
	Returns centroids of the native faces in map CRS.

bool	contains (const QgsMesh::ElementType &type) const
	Returns whether the mesh contains mesh elements of given type.

const QVector< QgsMeshVertex > &	edgeCentroids () const
	Returns centroids of the native edges in map CRS.

QList< int >	edgeIndexesForRectangle (const QgsRectangle &rectangle) const
	Finds indexes of edges intersecting given bounding box It uses spatial indexing.

const QVector< QgsMeshEdge > &	edges () const
	Returns edges.

const QVector< int > &	edgesToNativeEdges () const
	Returns mapping between edges and original edges.

QgsRectangle	extent () const
	Returns the extent of the triangular mesh in map coordinates.

const QVector< QgsMeshVertex > &	faceCentroids () const
	Returns centroids of the native faces in map CRS.

QList< int >	faceIndexesForRectangle (const QgsRectangle &rectangle) const
	Finds indexes of triangles intersecting given bounding box It uses spatial indexing.

int	faceIndexForPoint (const QgsPointXY &point) const
	Finds index of triangle at given point It uses spatial indexing.

int	faceIndexForPoint_v2 (const QgsPointXY &point) const
	Finds index of triangle at given point It uses spatial indexing and don't use geos to be faster.

int	levelOfDetail () const
	Returns the corresponding index of level of detail on which this mesh is associated.

QgsRectangle	nativeExtent ()
	Returns the extent of the mesh in the native mesh coordinates system, returns empty extent if the transformation fails.

int	nativeFaceIndexForPoint (const QgsPointXY &point) const
	Finds index of native face at given point It uses spatial indexing.

QList< int >	nativeFaceIndexForRectangle (const QgsRectangle &rectangle) const
	Finds indexes of native faces which bounding boxes intersect given bounding box It uses spatial indexing.

QgsMeshVertex	nativeToTriangularCoordinates (const QgsMeshVertex &vertex) const
	Transforms the vertex from native coordinates system to triangular mesh coordinates system.

void	reverseChanges (const Changes &changes, const QgsMesh &nativeMesh)
	Reverses the changes on the triangular mesh (see Changes)

QVector< QgsTriangularMesh * >	simplifyMesh (double reductionFactor, int minimumTrianglesCount=10) const
	Returns simplified meshes.

QgsPointXY	transformFromLayerToTrianglesCoordinates (const QgsPointXY &point) const
	Transforms a point from layer coordinates system to triangular Mesh coordinates system.

const QVector< QgsMeshFace > &	triangles () const
	Returns triangles.

const QVector< int > &	trianglesToNativeFaces () const
	Returns mapping between triangles and original faces.

QgsMeshVertex	triangularToNativeCoordinates (const QgsMeshVertex &vertex) const
	Transforms the vertex from triangular mesh coordinates system to native coordinates system.

bool	update (QgsMesh *nativeMesh)
	Constructs triangular mesh from layer's native mesh using the coordinate transform already set.

bool	update (QgsMesh *nativeMesh, const QgsCoordinateTransform &transform)
	Constructs triangular mesh from layer's native mesh and transform to destination CRS.

QVector< QVector3D >	vertexNormals (float vertScale) const
	Calculates and returns normal vector on each vertex that is part of any face.

const QVector< QgsMeshVertex > &	vertices () const
	Returns vertices in map coordinate system.

Friends
class	TestQgsTriangularMesh

Detailed Description

Triangular/Derived Mesh is mesh with vertices in map coordinates.

It creates spatial index for identification of a triangle that contains a particular point on the map.

Note: The API is considered EXPERIMENTAL and can be changed without a notice

Since: QGIS 3.2

Definition at line 51 of file qgstriangularmesh.h.

Constructor & Destructor Documentation

◆ QgsTriangularMesh()

QgsTriangularMesh::QgsTriangularMesh ( )

default

◆ ~QgsTriangularMesh()

QgsTriangularMesh::~QgsTriangularMesh ( )

default

Member Function Documentation

◆ applyChanges()

void QgsTriangularMesh::applyChanges ( const Changes & changes )

Applies the changes on the triangular mesh (see Changes)

Since: QGIS 3.22

Definition at line 729 of file qgstriangularmesh.cpp.

◆ averageTriangleSize()

double QgsTriangularMesh::averageTriangleSize ( ) const

Returns the average size of triangles in map unit.

It is calculated using the maximum of the height/width of the bounding box of each triangles.

Since: QGIS 3.14

Definition at line 149 of file qgstriangularmesh.cpp.

◆ centroids()

const QVector< QgsMeshVertex > & QgsTriangularMesh::centroids ( ) const

Returns centroids of the native faces in map CRS.

Deprecated:: QGIS 3.14. Use faceCentroids() instead.

Definition at line 372 of file qgstriangularmesh.cpp.

◆ contains()

bool QgsTriangularMesh::contains ( const QgsMesh::ElementType & type ) const

Returns whether the mesh contains mesh elements of given type.

Since: QGIS 3.14

Definition at line 334 of file qgstriangularmesh.cpp.

◆ edgeCentroids()

const QVector< QgsMeshVertex > & QgsTriangularMesh::edgeCentroids ( ) const

Returns centroids of the native edges in map CRS.

Since: QGIS 3.14

Definition at line 382 of file qgstriangularmesh.cpp.

◆ edgeIndexesForRectangle()

QList< int > QgsTriangularMesh::edgeIndexesForRectangle ( const QgsRectangle & rectangle ) const

Finds indexes of edges intersecting given bounding box It uses spatial indexing.

Parameters

rectangle bounding box in map coordinate system

Returns: edges indexes that intersect the rectangle

Definition at line 470 of file qgstriangularmesh.cpp.

◆ edges()

const QVector< QgsMeshEdge > & QgsTriangularMesh::edges ( ) const

Returns edges.

Definition at line 367 of file qgstriangularmesh.cpp.

◆ edgesToNativeEdges()

const QVector< int > & QgsTriangularMesh::edgesToNativeEdges ( ) const

Returns mapping between edges and original edges.

Definition at line 392 of file qgstriangularmesh.cpp.

◆ extent()

QgsRectangle QgsTriangularMesh::extent ( ) const

Returns the extent of the triangular mesh in map coordinates.

Returns: bounding box of the triangular mesh

Since: QGIS 3.14

Definition at line 315 of file qgstriangularmesh.cpp.

◆ faceCentroids()

const QVector< QgsMeshVertex > & QgsTriangularMesh::faceCentroids ( ) const

Returns centroids of the native faces in map CRS.

Since: QGIS 3.14

Definition at line 377 of file qgstriangularmesh.cpp.

◆ faceIndexesForRectangle()

QList< int > QgsTriangularMesh::faceIndexesForRectangle ( const QgsRectangle & rectangle ) const

Finds indexes of triangles intersecting given bounding box It uses spatial indexing.

Parameters

rectangle bounding box in map coordinate system

Returns: triangle indexes that intersect the rectangle

Since: QGIS 3.4

Definition at line 465 of file qgstriangularmesh.cpp.

◆ faceIndexForPoint()

int QgsTriangularMesh::faceIndexForPoint ( const QgsPointXY & point ) const

Finds index of triangle at given point It uses spatial indexing.

Parameters

point point in map coordinate system

Returns: triangle index that contains the given point, -1 if no such triangle exists

Since: QGIS 3.4

Definition at line 419 of file qgstriangularmesh.cpp.

◆ faceIndexForPoint_v2()

int QgsTriangularMesh::faceIndexForPoint_v2 ( const QgsPointXY & point ) const

Finds index of triangle at given point It uses spatial indexing and don't use geos to be faster.

Parameters

point point in map coordinate system

Returns: triangle index that contains the given point, -1 if no such triangle exists

Since: QGIS 3.12

Definition at line 452 of file qgstriangularmesh.cpp.

◆ levelOfDetail()

int QgsTriangularMesh::levelOfDetail ( ) const

Returns the corresponding index of level of detail on which this mesh is associated.

0: base mesh
1: first simplified mesh
2: second simplified mesh (lower level of detail)
...

Since: QGIS 3.14

Definition at line 329 of file qgstriangularmesh.cpp.

◆ nativeExtent()

QgsRectangle QgsTriangularMesh::nativeExtent ( )

Returns the extent of the mesh in the native mesh coordinates system, returns empty extent if the transformation fails.

Since: QGIS 3.22

Definition at line 292 of file qgstriangularmesh.cpp.

◆ nativeFaceIndexForPoint()

int QgsTriangularMesh::nativeFaceIndexForPoint ( const QgsPointXY & point ) const

Finds index of native face at given point It uses spatial indexing.

Parameters

point point in map coordinate system

Returns: native face index that contains the given point, -1 if no such faces exists

Since: QGIS 3.22

Definition at line 432 of file qgstriangularmesh.cpp.

◆ nativeFaceIndexForRectangle()

QList< int > QgsTriangularMesh::nativeFaceIndexForRectangle ( const QgsRectangle & rectangle ) const

Finds indexes of native faces which bounding boxes intersect given bounding box It uses spatial indexing.

Parameters

rectangle bounding box in map coordinate system

Returns: native face indexes that have bounding box that intersect the rectangle

Since: QGIS 3.22

Definition at line 444 of file qgstriangularmesh.cpp.

◆ nativeToTriangularCoordinates()

QgsMeshVertex QgsTriangularMesh::nativeToTriangularCoordinates ( const QgsMeshVertex & vertex ) const

Transforms the vertex from native coordinates system to triangular mesh coordinates system.

Returns empty vertex if the transform fails.

Since: QGIS 3.22

Definition at line 282 of file qgstriangularmesh.cpp.

◆ reverseChanges()

void QgsTriangularMesh::reverseChanges	(	const Changes &	changes,
		const QgsMesh &	nativeMesh
	)

Reverses the changes on the triangular mesh (see Changes)

Since: QGIS 3.22

Definition at line 861 of file qgstriangularmesh.cpp.

◆ simplifyMesh()

QVector< QgsTriangularMesh * > QgsTriangularMesh::simplifyMesh	(	double	reductionFactor,
		int	minimumTrianglesCount = `10`
	)		const

Returns simplified meshes.

The first simplified mesh is simplified with a goal of a number of triangles equal to the number of triangles of the base mesh divided by the reduction factor. For the following mesh the same reduction factor is used with the preceding goal of number of triangles. There are as many simplified meshes as necessary to have the minimum triangles count on the last simplified mesh.

The caller has to take the ownership of returned meshes.

Not implemented for Edge meshes and Mixed meshes

Parameters

reductionFactor	is the factor used to reduce the number of triangles of the mesh
minimumTrianglesCount	is the minimal faces count on simplified mesh

Since: QGIS 3.14

Definition at line 503 of file qgstriangularmesh.cpp.

◆ transformFromLayerToTrianglesCoordinates()

QgsPointXY QgsTriangularMesh::transformFromLayerToTrianglesCoordinates ( const QgsPointXY & point ) const

Transforms a point from layer coordinates system to triangular Mesh coordinates system.

Parameters

point point in layer coordinate system

Returns: point in triangular mesh coordinate

Since: QGIS 3.22

Definition at line 397 of file qgstriangularmesh.cpp.

◆ triangles()

const QVector< QgsMeshFace > & QgsTriangularMesh::triangles ( ) const

Returns triangles.

Definition at line 362 of file qgstriangularmesh.cpp.

◆ trianglesToNativeFaces()

const QVector< int > & QgsTriangularMesh::trianglesToNativeFaces ( ) const

Returns mapping between triangles and original faces.

Definition at line 387 of file qgstriangularmesh.cpp.

◆ triangularToNativeCoordinates()

QgsMeshVertex QgsTriangularMesh::triangularToNativeCoordinates ( const QgsMeshVertex & vertex ) const

Transforms the vertex from triangular mesh coordinates system to native coordinates system.

Returns empty vertex if the transform fails.

Since: QGIS 3.22

Definition at line 287 of file qgstriangularmesh.cpp.

◆ update() [1/2]

bool QgsTriangularMesh::update ( QgsMesh * nativeMesh )

Constructs triangular mesh from layer's native mesh using the coordinate transform already set.

Populates spatial index.

Parameters

nativeMesh QgsMesh to access native vertices and faces

Returns: true if the mesh is effectivly updated, and false if not

Note: if the coordinate transform is not already set, it uses the native mesh CRS

Since: QGIS 3.28

Definition at line 257 of file qgstriangularmesh.cpp.

◆ update() [2/2]

bool QgsTriangularMesh::update	(	QgsMesh *	nativeMesh,
		const QgsCoordinateTransform &	transform
	)

Constructs triangular mesh from layer's native mesh and transform to destination CRS.

Populates spatial index.

Parameters

nativeMesh	QgsMesh to access native vertices and faces
transform	Transformation from layer CRS to destination (e.g. map) CRS. With invalid transform, it keeps the native mesh CRS

Returns: true if the mesh is effectivly updated, and false if not

Definition at line 157 of file qgstriangularmesh.cpp.

◆ vertexNormals()

QVector< QVector3D > QgsTriangularMesh::vertexNormals ( float vertScale ) const

Calculates and returns normal vector on each vertex that is part of any face.

Returns: all normals at vertices

Since: QGIS 3.12

Definition at line 475 of file qgstriangularmesh.cpp.

◆ vertices()

const QVector< QgsMeshVertex > & QgsTriangularMesh::vertices ( ) const

Returns vertices in map coordinate system.

The list of consist of vertices from native mesh (0-N) and extra vertices needed to create triangles (N+1 - len)

Definition at line 357 of file qgstriangularmesh.cpp.

Friends And Related Symbol Documentation

◆ TestQgsTriangularMesh

friend class TestQgsTriangularMesh

friend

Definition at line 384 of file qgstriangularmesh.h.

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

/build/qgis-3.41.0+git20241122+3440c17df1d+99sid/src/core/mesh/qgstriangularmesh.h
/build/qgis-3.41.0+git20241122+3440c17df1d+99sid/src/core/mesh/qgstriangularmesh.cpp

Classes

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ QgsTriangularMesh()

◆ ~QgsTriangularMesh()

Member Function Documentation

◆ applyChanges()

◆ averageTriangleSize()

◆ centroids()

◆ contains()

◆ edgeCentroids()

◆ edgeIndexesForRectangle()

◆ edges()

◆ edgesToNativeEdges()

◆ extent()

◆ faceCentroids()

◆ faceIndexesForRectangle()

◆ faceIndexForPoint()

◆ faceIndexForPoint_v2()

◆ levelOfDetail()

◆ nativeExtent()

◆ nativeFaceIndexForPoint()

◆ nativeFaceIndexForRectangle()

◆ nativeToTriangularCoordinates()

◆ reverseChanges()

◆ simplifyMesh()

◆ transformFromLayerToTrianglesCoordinates()

◆ triangles()

◆ trianglesToNativeFaces()

◆ triangularToNativeCoordinates()

◆ update() [1/2]

◆ update() [2/2]

◆ vertexNormals()

◆ vertices()

Friends And Related Symbol Documentation

◆ TestQgsTriangularMesh