Class: QgsSfcgalGeometry¶

Wraps SFCGAL geometry object.

SfcgalGeometry geometry type.

Added in version 4.0.

List of all members, including inherited members

Methods

`addMValue`	Adds a m-dimension to the geometry, initialized to a preset value (existing M values remains unchanged).
`addZValue`	Adds a z-dimension to the geometry, initialized to a preset value (existing Z values remains unchanged).
`approximateMedialAxis`	Calculate a 2D approximate medial axis of geom based on its straight skeleton.
`area`	Computes the area of geom.
`asQgisGeometry`	Returns the geometry converted to a QGIS geometry object.
`asWkb`	Export the geometry as WKB
`asWkt`	Export the geometry as WKT
`boundary`	Returns the closure of the combinatorial boundary of the geometry (ie the topological boundary of the geometry).
`buffer2D`	Calculate a 2D buffer where all points are at distance from the original geometry.
`buffer3D`	Calculate a 3D buffer where all points are at distance from the original geometry.
`centroid`	Calculates the centroid of this geometry.
`clearCache`	Clears any cached parameters associated with the geometry, e.g., bounding boxes
`clone`	Clones the geometry by performing a deep copy
`combine`	Calculate the combination of this and geomList.
`convexHull`	Calculate the convex hull (bounding box).
`covers`	Cover test on 2D or 3D geometries Checks if this covers otherGeom.
`difference`	Calculate the difference of this and otherGeom.
`dimension`	Returns the inherent dimension of the geometry.
`dropMValue`	Drops the m coordinate of the geometry
`dropZValue`	Drops the z coordinate of the geometry
`envelope`	Calculate the envelope (bounding box).
`extrude`	Calculate an extrusion of the original geometry.
`fuzzyEqual`	Returns true if this == other geometry modulo epsilon distance
`geometryType`	Returns type of the geometry as a OGC string in CamelCase
`intersection`	Calculate the intersection of this and otherGeom.
`intersects`	Checks if otherGeom intersects this.
`isEmpty`	Checks if geom is empty.
`isSimple`	Checks this geometry is simple.
`isValid`	Checks if geom is valid.
`length`	Computes the max length of geom.
`partCount`	Returns the geom part count.
`primitiveAsPolyhedralSurface`	Converts the current primitive to geometry.
`primitiveParameter`	Returns the parameter value according to its name
`primitiveParameters`	Returns the list of available parameter description for this primitive.
`primitiveSetParameter`	Updates parameter value
`primitiveTransform`	Returns the primitive transform matrix.
`rotate2D`	2D Rotate this geometry around point center by angle angle
`rotate3D`	3D Rotate this geometry around axis axisVector by angle angle
`scale`	Scale this geometry by vector scaleFactor.
`simplify`	Simplifies a geometry using the CGAL algorithm
`swapXy`	Swaps the x and y coordinates of the geometry
`toPolyhedralSurface`	Converts the geometry to a PolyhedralSurface geometry.
`toSolid`	Converts the geometry to a Solid geometry.
`transform`	Apply 3D matrix transform mat to geometry geom
`translate`	Translate this geometry by vector translation.
`triangulate`	Triangulates this geometry using constraint 2D Delaunay Triangulation (keep Z if defined)
`volume`	Computes the volume of the primitive prim.
`wkbType`	Returns type of the geometry as a WKB type (point / linestring / polygon etc.)

Static Methods

`createCube`	Create a cube primitive
`fromWkb`	Creates a new geometry from a WKB byte pointer
`fromWkt`	Creates a new geometry from a WKT string.

class qgis.core.QgsSfcgalGeometry[source]¶

Bases: object

__init__(): Constructor for an empty SFCGAL geometry geometry.

__init__(qgsGeom: QgsAbstractGeometry | None)

Constructor with QgsAbstractGeometry pointer.

Will not take ownership.

Raises:: QgsSfcgalException – if an error was encountered during the operation
Parameters:: qgsGeom (Optional[QgsAbstractGeometry])

__init__(qgsGeom: QgsAbstractGeometry)

Constructor with QgsAbstractGeometry reference.

Raises:: QgsSfcgalException – if an error was encountered during the operation
Parameters:: qgsGeom (QgsAbstractGeometry)

__init__(qgsGeom: QgsGeometry)

Constructor with QgsGeometry reference.

Raises:: QgsSfcgalException – if an error was encountered during the operation
Parameters:: qgsGeom (QgsGeometry)

__init__(wkt: str | None)

Constructor from WKT

Raises:: QgsSfcgalException – if an error was encountered during the operation
Parameters:: wkt (Optional[str])

__init__(otherGeom: QgsSfcgalGeometry)

Copy constructor

Raises:: QgsSfcgalException – if an error was encountered during the operation
Parameters:: otherGeom (QgsSfcgalGeometry)

addMValue(self, mValue: float = 0) → bool[source]¶

Adds a m-dimension to the geometry, initialized to a preset value (existing M values remains unchanged).

Parameters:: mValue (float = 0) – m value to use
Return type:: bool
Returns:: true if success

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

addZValue(self, zValue: float = 0) → bool[source]¶

Adds a z-dimension to the geometry, initialized to a preset value (existing Z values remains unchanged).

Parameters:: zValue (float = 0) – z value to use
Return type:: bool
Returns:: true if success

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

approximateMedialAxis(self) → QgsSfcgalGeometry | None¶

Calculate a 2D approximate medial axis of geom based on its straight skeleton. The approximate medial axis is a simplified representation of a shape’s central skeleton It the geometry is 3D, the approximate medial axis will be calculated from its 2D projection If the operation fails, a null pointer is returned.

Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry as 2D multilinestring
Raises:: QgsSfcgalException – if an error was encountered during the operation

area(self, withDiscretization: bool = False) → float[source]¶

Computes the area of geom.

Parameters:: withDiscretization (bool = False) – If true, the area is computed using the real discretization with radial segments. If false, the area is computed for a perfect primitive. Defaults to false.
Return type:: float
Returns:: geometry area
Raises:: QgsSfcgalException – if an error was encountered during the operation

asQgisGeometry(self) → QgsAbstractGeometry | None¶

Returns the geometry converted to a QGIS geometry object. This method is slow to call, as it always involves re-conversion of the underlying SFCGAL geometry object.

Raises:: QgsSfcgalException – if an error was encountered during the operation
Return type:: Optional[QgsAbstractGeometry]

asWkb(self, flags: QgsAbstractGeometry.WkbFlag = QgsAbstractGeometry.WkbFlags()) → QByteArray[source]¶

Export the geometry as WKB

Parameters:: flags (QgsAbstractGeometry.WkbFlag = QgsAbstractGeometry.WkbFlags()) – argument specifies flags controlling WKB export behavior.
Return type:: QByteArray
Returns:: WKB data
Raises:: QgsSfcgalException – if an error was encountered during the operation

asWkt(self, precision: int = -1) → str[source]¶

Export the geometry as WKT

Parameters:: precision (int = -1) – Floating point precision for WKT coordinates. Setting to -1 yields rational number WKT (not decimal) f.e. “Point(1/3, 1/6, 1/4)”. Note that this will produce WKT which is not compatible with other QGIS methods or external libraries.
Return type:: str
Returns:: WKT data
Raises:: QgsSfcgalException – if an error was encountered during the operation

boundary(self) → QgsSfcgalGeometry | None¶

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.

Return type:: Optional[QgsSfcgalGeometry]
Returns:: boundary for geometry. May be None for some geometry types.

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

buffer2D(self, radius: float, segments: int, joinStyle: Qgis.JoinStyle) → QgsSfcgalGeometry | None¶

Calculate a 2D buffer where all points are at distance from the original geometry. A negative distance shrinks the geometry rather than expanding it. If the operation fails, a null pointer is returned.

Parameters:

radius (float) – the buffer radius
segments (int) – the number of segments to use for approximating curved
joinStyle (Qgis.JoinStyle) – the type of buffer to compute. Only round is supported.

Return type:

Optional[QgsSfcgalGeometry]

Returns:

new geometry

Raises:

QgsSfcgalException – if an error was encountered during the operation

buffer3D(self, radius: float, segments: int, joinStyle3D: Qgis.JoinStyle3D) → QgsSfcgalGeometry | None¶

Calculate a 3D buffer where all points are at distance from the original geometry. A negative distance shrinks the geometry rather than expanding it. It is limited to Point and LineString. If the operation fails, a null pointer is returned.

Parameters:

radius (float) – the buffer radius
segments (int) – the number of segments to use for approximating curved
joinStyle3D (Qgis.JoinStyle3D) – the type of buffer to compute

Return type:

Optional[QgsSfcgalGeometry]

Returns:

new geometry

Raises:

QgsSfcgalException – if an error was encountered during the operation

centroid(self) → QgsPoint[source]¶

Calculates the centroid of this geometry.

Return type:: QgsPoint
Returns:: geometry centroid

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

clearCache(self)[source]¶: Clears any cached parameters associated with the geometry, e.g., bounding boxes

clone(self) → QgsSfcgalGeometry | None¶

Clones the geometry by performing a deep copy

Return type:: Optional[QgsSfcgalGeometry]

combine(self, geomList: Iterable[QgsAbstractGeometry]) → QgsSfcgalGeometry | None¶

Calculate the combination of this and geomList.

Parameters:: geomList (Iterable[QgsAbstractGeometry]) – list of geometries to perform the operation
Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry
Raises:: QgsSfcgalException – if an error was encountered during the operation

convexHull(self) → QgsSfcgalGeometry | None¶

Calculate the convex hull (bounding box).

Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry
Raises:: QgsSfcgalException – if an error was encountered during the operation

covers(self, otherGeom: QgsSfcgalGeometry) → bool[source]¶

Cover test on 2D or 3D geometries Checks if this covers otherGeom. A 3D covers test is conducted when at least one geometry is 3D; otherwise, a 2D covers test is carried out.

Parameters:: otherGeom (QgsSfcgalGeometry) – second geometry to perform the operation
Return type:: bool
Returns:: true if coverage exists
Raises:: QgsSfcgalException – if an error was encountered during the operation

static createCube(size: float) → QgsSfcgalGeometry | None¶

Create a cube primitive

Parameters:

size (float) – the cube size

Raises:

QgsSfcgalException – if an error was encountered during the operation
QgsNotSupportedException – on QGIS builds based on SFCGAL < 2.3.

Return type:

Optional[QgsSfcgalGeometry]

difference(self, otherGeom: QgsAbstractGeometry | None) → QgsSfcgalGeometry | None¶

Calculate the difference of this and otherGeom.

Parameters:: otherGeom (Optional[QgsAbstractGeometry]) – geometry to perform the operation
Returns:: new geometry
Raises:: QgsSfcgalException – if an error was encountered during the operation

difference(self, otherGeom: QgsSfcgalGeometry) -> Optional[QgsSfcgalGeometry] Calculate the difference of this and otherGeom.

Parameters:: otherGeom – geometry to perform the operation
Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry
Raises:: QgsSfcgalException – if an error was encountered during the operation

dimension(self) → int[source]¶

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.

Return type:: int
Returns:: geometry dimension

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

dropMValue(self) → bool[source]¶

Drops the m coordinate of the geometry

Return type:: bool
Returns:: true if success

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

dropZValue(self) → bool[source]¶

Drops the z coordinate of the geometry

Return type:: bool
Returns:: true if success

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

envelope(self) → QgsSfcgalGeometry | None¶

Calculate the envelope (bounding box).

Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

extrude(self, extrusion: QgsVector3D) → QgsSfcgalGeometry | None¶

Calculate an extrusion of the original geometry. If the operation fails, a null pointer is returned.

Parameters:: extrusion (QgsVector3D) – extrusion vector (2D or 3D)
Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry
Raises:: QgsSfcgalException – if an error was encountered during the operation

static fromWkb(wkbPtr: QgsConstWkbPtr) → QgsSfcgalGeometry | None¶

Creates a new geometry from a WKB byte pointer

Parameters:: wkbPtr (QgsConstWkbPtr) – WKB byte pointer
Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry from WKB
Raises:: QgsSfcgalException – if an error was encountered during the operation

static fromWkt(wkt: str | None) → QgsSfcgalGeometry | None¶

Creates a new geometry from a WKT string.

Parameters:: wkt (Optional[str]) – WTK string
Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry from WKT
Raises:: QgsSfcgalException – if an error was encountered during the operation

fuzzyEqual(self, other: QgsSfcgalGeometry, epsilon: float) → bool[source]¶

Returns true if this == other geometry modulo epsilon distance

Parameters:

other (QgsSfcgalGeometry) – geometry to perform the operation
epsilon (float) – tolerance

Return type:

bool

Returns:

true if this == other geometry modulo epsilon distance

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on SFCGAL 2.0.
QgsSfcgalException – if an error was encountered during the operation

geometryType(self) → str[source]¶

Returns type of the geometry as a OGC string in CamelCase

Return type:: str
Returns:: type of the geometry as a OGC string in CamelCase

This method requires a QGIS build based on SFCGAL 2.1 or later.

Raises:

QgsNotSupportedException – when working with primitive and SFCGAL is less than 2.3.
QgsSfcgalException – if an error was encountered during the operation

intersection(self, otherGeom: QgsAbstractGeometry | None) → QgsSfcgalGeometry | None¶

Calculate the intersection of this and otherGeom.

Parameters:: otherGeom (Optional[QgsAbstractGeometry]) – geometry to perform the operation
Returns:: new geometry
Raises:: QgsSfcgalException – if an error was encountered during the operation

intersection(self, otherGeom: QgsSfcgalGeometry) -> Optional[QgsSfcgalGeometry] Calculate the intersection of this and otherGeom.

Parameters:: otherGeom – geometry to perform the operation
Return type:: Optional[QgsSfcgalGeometry]
Returns:: new geometry
Raises:: QgsSfcgalException – if an error was encountered during the operation

intersects(self, otherGeom: QgsAbstractGeometry | None) → bool[source]¶

Checks if otherGeom intersects this.

Parameters:: otherGeom (Optional[QgsAbstractGeometry]) – geometry to perform the operation
Returns:: true if intersection exists
Raises:: QgsSfcgalException – if an error was encountered during the operation

intersects(self, otherGeom: QgsSfcgalGeometry) -> bool Checks if otherGeom intersects this.

Parameters:: otherGeom – geometry to perform the operation
Return type:: bool
Returns:: true if intersection exists
Raises:: QgsSfcgalException – if an error was encountered during the operation

isEmpty(self) → bool[source]¶

Checks if geom is empty.

Return type:: bool
Returns:: true if empty
Raises:: QgsSfcgalException – if an error was encountered during the operation

isSimple(self) → bool[source]¶

Checks this geometry is simple.