Class: QgsGeometry

class qgis.core.QgsGeometry

Bases: sip.wrapper

A geometry is the spatial representation of a feature.

QgsGeometry acts as a generic container for geometry objects. QgsGeometry objects are implicitly shared, so making copies of geometries is inexpensive. The geometry container class can also be stored inside a QVariant object.

The actual geometry representation is stored as a QgsAbstractGeometry within the container, and can be accessed via the get() method or set using the set() method. This gives access to the underlying raw geometry primitive, such as the point, line, polygon, curve or other geometry subclasses.

Note

QgsGeometry objects are inherently Cartesian/planar geometries. They have no concept of geodesy, and none of the methods or properties exposed from the QgsGeometry API (or QgsAbstractGeometry subclasses) utilize geodesic calculations. Accordingly, properties like length() and area() or spatial operations like buffer() are always calculated using strictly Cartesian mathematics. In contrast, the QgsDistanceArea class exposes methods for working with geodesic calculations and spatial operations on geometries, and should be used whenever calculations which account for the curvature of the Earth (or any other celestial body) are required.

QgsGeometry() Constructor

QgsGeometry(QgsGeometry) Copy constructor will prompt a deep copy of the object

QgsGeometry(geom: QgsAbstractGeometry) Creates a geometry from an abstract geometry object. Ownership of geom is transferred.

New in version 2.10:

Enums

BufferSide	Bases: enum.IntEnum
EndCapStyle	Bases: enum.IntEnum
JoinStyle	Bases: enum.IntEnum
OperationResult	alias of GeometryOperationResult
ValidationMethod	alias of GeometryValidationEngine
ValidityFlag	alias of GeometryValidityFlag

Methods

addPart	Adds a new part to this geometry.
addPartGeometry	Adds a new island polygon to a multipolygon feature
addPoints	Adds a new part to a the geometry.
addPointsXY	Adds a new part to a the geometry.
addRing	Adds a new ring to this geometry.
adjacentVertices	Returns the indexes of the vertices before and after the given vertex index.
angleAtVertex	Returns the bisector angle for this geometry at the specified vertex.
applyDashPattern	Applies a dash pattern to a geometry, returning a MultiLineString geometry which is the input geometry stroked along each line/ring with the specified pattern.
area	Returns the planar, 2-dimensional area of the geometry.
asGeometryCollection	Returns contents of the geometry as a list of geometries
asJson	Exports the geometry to a GeoJSON string.
asMultiPoint	Returns the contents of the geometry as a multi-point.
asMultiPolygon	Returns the contents of the geometry as a multi-polygon.
asMultiPolyline	Returns the contents of the geometry as a multi-linestring.
asPoint	Returns the contents of the geometry as a 2-dimensional point.
asPolygon	Returns the contents of the geometry as a polygon.
asPolyline	Returns the contents of the geometry as a polyline.
asQPointF	Returns contents of the geometry as a QPointF if wkbType is WKBPoint, otherwise returns a null QPointF.
asQPolygonF	Returns contents of the geometry as a QPolygonF.
asWkb	Export the geometry to WKB
asWkt	Exports the geometry to WKT
avoidIntersections	Modifies geometry to avoid intersections with the layers specified in project properties
avoidIntersectionsV2	Modifies geometry to avoid intersections with the layers specified in project properties
boundingBox	Returns the bounding box of the geometry.
boundingBox3D	Returns the 3D bounding box of the geometry.
boundingBoxIntersects	Returns True if the bounding box of this geometry intersects with a rectangle.
buffer	Returns a buffer region around this geometry having the given width and with a specified number of segments used to approximate curves
centroid	Returns the center of mass of a geometry.
clipped	Clips the geometry using the specified rectangle.
closestSegmentWithContext	Searches for the closest segment of geometry to the given point
closestVertex	Returns the vertex closest to the given point, the corresponding vertex index, squared distance snap point / target point and the indices of the vertices before and after the closest vertex.
closestVertexWithContext	Searches for the closest vertex in this geometry to the given point.
coerceToType	Attempts to coerce this geometry into the specified destination type.
collectGeometry	Creates a new multipart geometry from a list of QgsGeometry objects
combine	Returns a geometry representing all the points in this geometry and other (a union geometry operation).
compare	Compares two geometry objects for equality within a specified tolerance.
concaveHull	Returns a possibly concave polygon that contains all the points in the geometry.
constGet	Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.
constParts	Returns Java-style iterator for traversal of parts of the geometry.
contains	Returns True if the geometry contains the point p.
convertGeometryCollectionToSubclass	Converts geometry collection to a the desired geometry type subclass (multi-point, multi-linestring or multi-polygon).
convertPointList	Upgrades a point list from QgsPointXY to QgsPoint
convertToCurvedMultiType	Converts a geometry into a multitype geometry of curve kind (when there is a corresponding curve type).
convertToCurves	Attempts to convert a non-curved geometry into a curved geometry type (e.g. LineString to CompoundCurve, Polygon to CurvePolygon).
convertToMultiType	Converts single type geometry into multitype geometry e.g. a polygon into a multipolygon geometry with one polygon If it is already a multipart geometry, it will return True and not change the geometry.
convertToSingleType	Converts multi type geometry into single type geometry e.g. a multipolygon into a polygon geometry.
convertToStraightSegment	Converts the geometry to straight line segments, if it is a curved geometry type.
convertToType	Try to convert the geometry to the requested type
convexHull	Returns the smallest convex polygon that contains all the points in the geometry.
createGeometryEngine	Creates and returns a new geometry engine representing the specified geometry.
createPolygonFromQPolygonF	Creates a QgsPolygonXYfrom a QPolygonF.
createPolylineFromQPolygonF	Creates a QgsPolylineXY from a QPolygonF.
createWedgeBuffer	Creates a wedge shaped buffer from a center point.
crosses	Returns True if the geometry crosses another geometry.
delaunayTriangulation	Returns the Delaunay triangulation for the vertices of the geometry.
deletePart	Deletes part identified by the part number
deleteRing	Deletes a ring in polygon or multipolygon.
deleteVertex	Deletes the vertex at the given position number and item (first number is index 0)
densifyByCount	Returns a copy of the geometry which has been densified by adding the specified number of extra nodes within each segment of the geometry.
densifyByDistance	Densifies the geometry by adding regularly placed extra nodes inside each segment so that the maximum distance between any two nodes does not exceed the specified distance.
difference	Returns a geometry representing the points making up this geometry that do not make up other.
disjoint	Returns True if the geometry is disjoint of another geometry.
distance	Returns the minimum distance between this geometry and another geometry.
distanceToVertex	Returns the distance along this geometry from its first vertex to the specified vertex.
draw	Draws the geometry onto a QPainter
equals	Test if this geometry is exactly equal to another geometry.
extendLine	Extends a (multi)line geometry by extrapolating out the start or end of the line by a specified distance.
extrude	Returns an extruded version of this geometry.
forcePolygonClockwise	Forces geometries to respect the exterior ring is clockwise, interior rings are counter-clockwise convention.
forcePolygonCounterClockwise	Forces geometries to respect the exterior ring is counter-clockwise, interior rings are clockwise convention.
forceRHR	Forces geometries to respect the Right-Hand-Rule, in which the area that is bounded by a polygon is to the right of the boundary.
frechetDistance	Returns the Fréchet distance between this geometry and geom, restricted to discrete points for both geometries.
frechetDistanceDensify	Returns the Fréchet distance between this geometry and geom, restricted to discrete points for both geometries.
fromBox3D	Creates a new geometry from a QgsBox3D object
fromMultiPointXY	Creates a new geometry from a QgsMultiPointXY object
fromMultiPolygonXY	Creates a new geometry from a QgsMultiPolygonXY.
fromMultiPolylineXY	Creates a new geometry from a QgsMultiPolylineXY object.
fromPoint	Creates a new geometry from a QgsPoint object.
fromPointXY	Creates a new geometry from a QgsPointXY object
fromPolygonXY	Creates a new polygon geometry from a list of lists of QgsPointXY.
fromPolyline	Creates a new LineString geometry from a list of QgsPoint points.
fromPolylineXY	Creates a new LineString geometry from a list of QgsPointXY points.
fromQPointF	Construct geometry from a QPointF
fromQPolygonF	Construct geometry from a QPolygonF.
fromRect	Creates a new geometry from a QgsRectangle
fromWkb	Set the geometry, feeding in the buffer containing OGC Well-Known Binary
fromWkt	Creates a new geometry from a WKT string
get	Returns a modifiable (non-const) reference to the underlying abstract geometry primitive.
hausdorffDistance	Returns the Hausdorff distance between this geometry and geom.
hausdorffDistanceDensify	Returns the Hausdorff distance between this geometry and geom.
insertVertex	Insert a new vertex before the given vertex index, ring and item (first number is index 0) If the requested vertex number (beforeVertex.back()) is greater than the last actual vertex on the requested ring and item, it is assumed that the vertex is to be appended instead of inserted.
interpolate	Returns an interpolated point on the geometry at the specified distance.
interpolateAngle	Returns the angle parallel to the linestring or polygon boundary at the specified distance along the geometry.
intersection	Returns a geometry representing the points shared by this geometry and other.
intersects	Returns True if this geometry exactly intersects with a rectangle.
isAxisParallelRectangle	Returns True if the geometry is a polygon that is almost an axis-parallel rectangle.
isEmpty	Returns True if the geometry is empty (eg a linestring with no vertices, or a collection with no geometries).
isGeosEqual	Compares the geometry with another geometry using GEOS.
isGeosValid	Checks validity of the geometry using GEOS.
isMultipart	Returns True if WKB of the geometry is of WKBMulti* type
isNull	Returns True if the geometry is null (ie, contains no underlying geometry accessible via get() or constGet() ).
isPolygonClockwise	Returns True if the Polygon is clockwise.
isPolygonCounterClockwise	Returns True if the Polygon is counter-clockwise.
isSimple	Determines whether the geometry is simple (according to OGC definition), i.e. it has no anomalous geometric points, such as self-intersection or self-tangency.
largestEmptyCircle	Constructs the Largest Empty Circle for a set of obstacle geometries, up to a specified tolerance.
lastError	Returns an error string referring to the last error encountered either when this geometry was created or when an operation was performed on the geometry.
length	Returns the planar, 2-dimensional length of geometry.
lineLocatePoint	Returns a distance representing the location along this linestring of the closest point on this linestring geometry to the specified point.
makeDifference	Returns the geometry formed by modifying this geometry such that it does not intersect the other geometry.
makeValid	Attempts to make an invalid geometry valid without losing vertices.
mapToPixel	Transforms the geometry from map units to pixels in place.
mergeLines	Merges any connected lines in a LineString/MultiLineString geometry and converts them to single line strings.
minimalEnclosingCircle	Returns the minimal enclosing circle for the geometry.
minimumClearance	Computes the minimum clearance of a geometry.
minimumClearanceLine	Returns a LineString whose endpoints define the minimum clearance of a geometry.
minimumWidth	Returns a linestring geometry which represents the minimum diameter of the geometry.
moveVertex	Moves the vertex at the given position number and item (first number is index 0) to the given coordinates.
nearestPoint	Returns the nearest (closest) point on this geometry to another geometry.
node	Returns a (Multi)LineString representing the fully noded version of a collection of linestrings.
normalize	Reorganizes the geometry into a normalized form (or "canonical" form).
offsetCurve	Returns an offset line at a given distance and side from an input line.
orientedMinimumBoundingBox	Returns the oriented minimum bounding box for the geometry, which is the smallest (by area) rotated rectangle which fully encompasses the geometry.
orthogonalize	Attempts to orthogonalize a line or polygon geometry by shifting vertices to make the geometries angles either right angles or flat lines.
overlaps	Returns True if the geometry overlaps another geometry.
parts	Returns Java-style iterator for traversal of parts of the geometry.
pointOnSurface	Returns a point guaranteed to lie on the surface of a geometry.
poleOfInaccessibility	Calculates the approximate pole of inaccessibility for a surface, which is the most distant internal point from the boundary of the surface.
polygonOrientation	Returns the orientation of the polygon.
polygonize	Creates a GeometryCollection geometry containing possible polygons formed from the constituent linework of a set of geometries.
randomPointsInPolygon	Returns a list of count random points generated inside a (multi)polygon geometry.
removeDuplicateNodes	Removes duplicate nodes from the geometry, wherever removing the nodes does not result in a degenerate geometry.
removeInteriorRings	Removes the interior rings from a (multi)polygon geometry.
requiresConversionToStraightSegments	Returns True if the geometry is a curved geometry type which requires conversion to display as straight line segments.
reshapeGeometry	Replaces a part of this geometry with another line
rotate	Rotate this geometry around the Z axis
roundWaves	Constructs rounded (sine-like) waves along the boundary of the geometry, with the specified wavelength and amplitude.
roundWavesRandomized	Constructs randomized rounded (sine-like) waves along the boundary of the geometry, with the specified wavelength and amplitude ranges.
set	Sets the underlying geometry store.
sharedPaths	Find paths shared between the two given lineal geometries (this and other).
shortestLine	Returns the shortest line joining this geometry to another geometry.
simplify	Returns a simplified version of this geometry using a specified tolerance value
simplifyCoverageVW	Operates on a coverage (represented as a list of polygonal geometry with exactly matching edge geometry) to apply a Visvalingam–Whyatt simplification to the edges, reducing complexity in proportion with the provided tolerance, while retaining a valid coverage (no edges will cross or touch after the simplification).
singleSidedBuffer	Returns a single sided buffer for a (multi)line geometry.
smooth	Smooths a geometry by rounding off corners using the Chaikin algorithm.
snappedToGrid	Returns a new geometry with all points or vertices snapped to the closest point of the grid.
splitGeometry	Splits this geometry according to a given line.
sqrDistToVertexAt	Returns the squared Cartesian distance between the given point to the given vertex index (vertex at the given position number, ring and item (first number is index 0))
squareWaves	Constructs square waves along the boundary of the geometry, with the specified wavelength and amplitude.
squareWavesRandomized	Constructs randomized square waves along the boundary of the geometry, with the specified wavelength and amplitude ranges.
subdivide	Subdivides the geometry.
symDifference	Returns a geometry representing the points making up this geometry that do not make up other.
taperedBuffer	Calculates a variable width buffer ("tapered buffer") for a (multi)curve geometry.
toggleCircularAtVertex	Converts the vertex at the given position from/to circular
touches	Returns True if the geometry touches another geometry.
transform	Transforms this geometry as described by the coordinate transform ct.
translate	Translates this geometry by dx, dy, dz and dm.
triangularWaves	Constructs triangular waves along the boundary of the geometry, with the specified wavelength and amplitude.
triangularWavesRandomized	Constructs randomized triangular waves along the boundary of the geometry, with the specified wavelength and amplitude ranges.
type	Returns type of the geometry as a Qgis.GeometryType
unaryUnion	Compute the unary union on a list of geometries.
unionCoverage	Optimized union algorithm for polygonal inputs that are correctly noded and do not overlap.
validateCoverage	Analyze a coverage (represented as a collection of polygonal geometry with exactly matching edge geometry) to find places where the assumption of exactly matching edges is not met.
validateGeometry	Validates geometry and produces a list of geometry errors.
variableWidthBufferByM	Calculates a variable width buffer for a (multi)linestring geometry, where the width at each node is taken from the linestring m values.
vertexAt	Returns coordinates of a vertex.
vertexIdFromVertexNr	Calculates the vertex ID from a vertex number.
vertexNrFromVertexId	Returns the vertex number corresponding to a vertex id.
vertices	Returns a read-only, Java-style iterator for traversal of vertices of all the geometry, including all geometry parts and rings.
voronoiDiagram	Creates a Voronoi diagram for the nodes contained within the geometry.
within	Returns True if the geometry is completely within another geometry.
wkbSize	Returns the length of the QByteArray returned by asWkb()
wkbType	Returns type of the geometry as a WKB type (point / linestring / polygon etc.)

Attributes

staticMetaObject

class BufferSide(value)

Bases: enum.IntEnum

Side of line to buffer.

New in version 3.22.

• SideLeft: Buffer to left of line

• SideRight: Buffer to right of line

baseClass

alias of Qgis

class EndCapStyle(value)

Bases: enum.IntEnum

End cap styles for buffers.

New in version 3.22.

• CapRound: Round cap

• CapFlat: Flat cap (in line with start/end of line)

• CapSquare: Square cap (extends past start/end of line by buffer distance)

baseClass

alias of Qgis

class Error

Bases: sip.wrapper

A geometry error.

hasWhere(self) → bool

True if the location available from where() is valid.

Return type:

bool

what(self) → str

A human readable error message containing details about the error.

Return type:

str

where(self) → QgsPointXY

The coordinates at which the error is located and should be visualized.

Return type:

QgsPointXY

class JoinStyle(value)

Bases: enum.IntEnum

Join styles for buffers.

New in version 3.22.

• JoinStyleRound: Use rounded joins

• JoinStyleMiter: Use mitered joins

• JoinStyleBevel: Use beveled joins

baseClass

alias of Qgis

OperationResult

alias of GeometryOperationResult

ValidationMethod

alias of GeometryValidationEngine

ValidityFlag

alias of GeometryValidityFlag

ValidityFlags

alias of GeometryValidityFlags

addPart(self, part: QgsAbstractGeometry, geomType: Qgis.GeometryType = Qgis.GeometryType.Unknown) → Qgis.GeometryOperationResult

Adds a new part to this geometry.

Parameters:

• part (QgsAbstractGeometry) – part to add (ownership is transferred)

• geomType (Qgis.GeometryType = Qgis.GeometryType.Unknown) – default geometry type to create if no existing geometry

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

addPartGeometry(self, newPart: QgsGeometry) → Qgis.GeometryOperationResult

Adds a new island polygon to a multipolygon feature

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

Note

available in python bindings as addPartGeometry

Parameters:

newPart (QgsGeometry) –

addPoints(self, points: Iterable[QgsPoint], geomType: Qgis.GeometryType = Qgis.GeometryType.Unknown) → Qgis.GeometryOperationResult

Adds a new part to a the geometry.

Parameters:

• points (Iterable[QgsPoint]) – points describing part to add

• geomType (Qgis.GeometryType = Qgis.GeometryType.Unknown) – default geometry type to create if no existing geometry

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

addPointsXY(self, points: Iterable[QgsPointXY], geomType: Qgis.GeometryType = Qgis.GeometryType.Unknown) → Qgis.GeometryOperationResult

Adds a new part to a the geometry.

Parameters:

• points (Iterable[QgsPointXY]) – points describing part to add

• geomType (Qgis.GeometryType = Qgis.GeometryType.Unknown) – default geometry type to create if no existing geometry

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

addRing(self, ring: Iterable[QgsPointXY]) → Qgis.GeometryOperationResult

Adds a new ring to this geometry. This makes only sense for polygon and multipolygons.

Parameters:

ring (Iterable[QgsPointXY]) – The ring to be added

Returns:

OperationResult a result code: success or reason of failure

addRing(self, ring: QgsCurve) -> Qgis.GeometryOperationResult Adds a new ring to this geometry. This makes only sense for polygon and multipolygons.

Parameters:

ring – The ring to be added

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

adjacentVertices(self, atVertex: int) → Tuple[int, int]

Returns the indexes of the vertices before and after the given vertex index.

This function takes into account the following factors:

# If the given vertex index is at the end of a linestring,

the adjacent index will be -1 (for “no adjacent vertex”)

# If the given vertex index is at the end of a linear ring

(such as in a polygon), the adjacent index will take into account the first vertex is equal to the last vertex (and will skip equal vertex positions).

Parameters:

atVertex (int) –

Return type:

Tuple[int, int]

angleAtVertex(self, vertex: int) → float

Returns the bisector angle for this geometry at the specified vertex.

Parameters:

vertex (int) – vertex index to calculate bisector angle at

Return type:

float

Returns:

bisector angle, in radians clockwise from north

See also

interpolateAngle()

New in version 3.0.

applyDashPattern(self, pattern: Iterable[float], startRule: Qgis.DashPatternLineEndingRule = Qgis.DashPatternLineEndingRule.NoRule, endRule: Qgis.DashPatternLineEndingRule = Qgis.DashPatternLineEndingRule.NoRule, adjustment: Qgis.DashPatternSizeAdjustment = Qgis.DashPatternSizeAdjustment.ScaleBothDashAndGap, patternOffset: float = 0) → QgsGeometry

Applies a dash pattern to a geometry, returning a MultiLineString geometry which is the input geometry stroked along each line/ring with the specified pattern.

The startRule and endRule options can be set to control how the dash pattern is adjusted at line endings. If a startRule or endRule is set, the adjustment option defines whether both dash and gaps, or only dash or gap sizes are adjusted to apply the rules.

The patternOffset option specifies how far along the pattern the result should start at. The offset is applied AFTER any start/end rules are applied.

New in version 3.24.

Parameters:

• pattern (Iterable[float]) –

• startRule (Qgis.DashPatternLineEndingRule = Qgis.DashPatternLineEndingRule.NoRule) –

• endRule (Qgis.DashPatternLineEndingRule = Qgis.DashPatternLineEndingRule.NoRule) –

• adjustment (Qgis.DashPatternSizeAdjustment = Qgis.DashPatternSizeAdjustment.ScaleBothDashAndGap) –

• patternOffset (float = 0) –

Return type:

QgsGeometry

area(self) → float

Returns the planar, 2-dimensional area of the geometry.

Warning

QgsGeometry objects are inherently Cartesian/planar geometries, and the area returned by this method is calculated using strictly Cartesian mathematics. In contrast, the QgsDistanceArea class exposes methods for calculating the areas of geometries using geodesic calculations which account for the curvature of the Earth (or any other celestial body).

See also

length()

New in version 1.5.

Return type:

float

asGeometryCollection(self) → List[QgsGeometry]

Returns contents of the geometry as a list of geometries

New in version 1.1.

Return type:

List[QgsGeometry]

asJson(self, precision: int = 17) → str

Exports the geometry to a GeoJSON string.

Parameters:

precision (int = 17) –

Return type:

str

asMultiPoint(self) → QgsMultiPointXY

Returns the contents of the geometry as a multi-point.

Any z or m values present in the geometry will be discarded.

This method works only with multi-point geometry types.

Raises:

• TypeError – if the geometry is not a multi-point type

• ValueError – if the geometry is null

Return type:

QgsMultiPointXY

asMultiPolygon(self) → QgsMultiPolygonXY

Returns the contents of the geometry as a multi-polygon.

Any z or m values present in the geometry will be discarded. If the geometry is a curved polygon type (such as a MultiSurface), it will be automatically segmentized.

This method works only with multi-polygon (or multi-curve polygon) geometry types.

Raises:

• TypeError – if the geometry is not a multi-polygon type

• ValueError – if the geometry is null

Return type:

QgsMultiPolygonXY

asMultiPolyline(self) → QgsMultiPolylineXY

Returns the contents of the geometry as a multi-linestring.

Any z or m values present in the geometry will be discarded. If the geometry is a curved line type (such as a MultiCurve), it will be automatically segmentized.

This method works only with multi-linestring (or multi-curve) geometry types.

Raises:

• TypeError – if the geometry is not a multi-linestring type

• ValueError – if the geometry is null

Return type:

QgsMultiPolylineXY

asPoint(self) → QgsPointXY

Returns the contents of the geometry as a 2-dimensional point.

Any z or m values present in the geometry will be discarded.

This method works only with single-point geometry types.

Raises:

• TypeError – if the geometry is not a single-point type (or a multipoint containing a single point)

• ValueError – if the geometry is null

Return type:

QgsPointXY

asPolygon(self) → QgsPolygonXY

Returns the contents of the geometry as a polygon.

Any z or m values present in the geometry will be discarded. If the geometry is a curved polygon type (such as a CurvePolygon), it will be automatically segmentized.

This method works only with single-polygon (or single-curve polygon) geometry types.

Raises:

• TypeError – if the geometry is not a single-polygon type

• ValueError – if the geometry is null

Return type:

QgsPolygonXY

asPolyline(self) → QgsPolylineXY

Returns the contents of the geometry as a polyline.

Any z or m values present in the geometry will be discarded. If the geometry is a curved line type (such as a CircularString), it will be automatically segmentized.

This method works only with single-line (or single-curve).

Raises:

• TypeError – if the geometry is not a single-line type

• ValueError – if the geometry is null

Return type:

QgsPolylineXY

asQPointF(self) → QPointF

Returns contents of the geometry as a QPointF if wkbType is WKBPoint, otherwise returns a null QPointF.

New in version 2.7.

Return type:

QPointF

asQPolygonF(self) → QPolygonF

Returns contents of the geometry as a QPolygonF.

If geometry is a linestring, then the result will be an open QPolygonF. If the geometry is a polygon, then the result will be a closed QPolygonF of the geometry’s exterior ring.

If the geometry is a multi-part geometry, then only the first part will be considered when converting to a QPolygonF.

New in version 2.7.

Return type:

QPolygonF

asWkb(self, flags: QgsAbstractGeometry.WkbFlags | QgsAbstractGeometry.WkbFlag = QgsAbstractGeometry.WkbFlags()) → QByteArray

Export the geometry to WKB

The optional flags argument specifies flags controlling WKB export behavior (since QGIS 3.14).

New in version 3.0.

Parameters:

flags (Union[QgsAbstractGeometry.WkbFlags) –

Return type:

QByteArray

asWkt(self, precision: int = 17) → str

Exports the geometry to WKT

Return type:

str

Returns:

True in case of success and False else

Note

precision parameter added in QGIS 2.4

Parameters:

precision (int = 17) –

avoidIntersections(self, avoidIntersectionsLayers: Iterable[QgsVectorLayer]) → int

Modifies geometry to avoid intersections with the layers specified in project properties

Parameters:

avoidIntersectionsLayers (Iterable[QgsVectorLayer]) – list of layers to check for intersections

Return type:

int

Returns:

0 in case of success, 1 if geometry is not of polygon type, 2 if avoid intersection would change the geometry type, 3 at least one geometry intersected is invalid. The algorithm may not work and return the same geometry as the input. You must fix your intersecting geometries. 4 if the geometry is not intersected by one of the geometries present in the provided layers.

New in version 1.5.

Deprecated since version QGIS: 3.34

avoidIntersectionsV2(self, avoidIntersectionsLayers: Iterable[QgsVectorLayer]) → Qgis.GeometryOperationResult

Modifies geometry to avoid intersections with the layers specified in project properties

Parameters:

avoidIntersectionsLayers (Iterable[QgsVectorLayer]) – list of layers to check for intersections

Return type:

Qgis.GeometryOperationResult

Returns:

Success in case of success InvalidInputGeometryType if geometry is not of polygon type GeometryTypeHasChanged if avoid intersection has changed the geometry type InvalidBaseGeometry at least one geometry intersected is invalid. The algorithm may not work and return the same geometry as the input. You must fix your intersecting geometries. NothingHappened if the geometry is not intersected by one of the geometries present in the provided layers.

New in version 3.34.

boundingBox(self) → QgsRectangle

Returns the bounding box of the geometry.

See also

orientedMinimumBoundingBox()

Return type:

QgsRectangle

boundingBox3D(self) → QgsBox3D

Returns the 3D bounding box of the geometry.

New in version 3.34.

Return type:

QgsBox3D

boundingBoxIntersects(self, rectangle: QgsRectangle) → bool

Returns True if the bounding box of this geometry intersects with a rectangle. Since this test only considers the bounding box of the geometry, is is very fast to calculate and handles invalid geometries.

See also

intersects()

New in version 3.0.

boundingBoxIntersects(self, geometry: QgsGeometry) -> bool Returns True if the bounding box of this geometry intersects with the bounding box of another geometry. Since this test only considers the bounding box of the geometries, is is very fast to calculate and handles invalid geometries.

See also

intersects()

New in version 3.0.

Parameters:

rectangle (QgsRectangle) –

Return type:

bool

buffer(self, distance: float, segments: int) → QgsGeometry

Returns a buffer region around this geometry having the given width and with a specified number of segments used to approximate curves

See also

singleSidedBuffer()

See also

taperedBuffer()

buffer(self, distance: float, segments: int, endCapStyle: Qgis.EndCapStyle, joinStyle: Qgis.JoinStyle, miterLimit: float) -> QgsGeometry Returns a buffer region around the geometry, with additional style options.

Parameters:

• distance (float) – buffer distance

• segments (int) – for round joins, number of segments to approximate quarter-circle

• endCapStyle – end cap style

• joinStyle – join style for corners in geometry

• miterLimit – limit on the miter ratio used for very sharp corners (JoinStyleMiter only)

See also

singleSidedBuffer()

See also

taperedBuffer()

New in version 2.4.

Return type:

QgsGeometry

centroid(self) → QgsGeometry

Returns the center of mass of a geometry.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Note

for line based geometries, the center point of the line is returned, and for point based geometries, the point itself is returned

See also

pointOnSurface()

See also

poleOfInaccessibility()

Return type:

QgsGeometry

clipped(self, rectangle: QgsRectangle) → QgsGeometry

Clips the geometry using the specified rectangle.

Performs a fast, non-robust intersection between the geometry and a rectangle. The returned geometry may be invalid.

New in version 3.0.

Parameters:

rectangle (QgsRectangle) –

Return type:

QgsGeometry

closestSegmentWithContext(self, point: QgsPointXY, epsilon: float = DEFAULT_SEGMENT_EPSILON) → Tuple[float, QgsPointXY, int, int]

Searches for the closest segment of geometry to the given point

Parameters:

• point (QgsPointXY) – Specifies the point for search

• epsilon (float = DEFAULT_SEGMENT_EPSILON) – epsilon for segment snapping

Return type:

Tuple[float, QgsPointXY, int, int]

Returns:

• The squared Cartesian distance is also returned in sqrDist, negative number on error

• minDistPoint: Receives the nearest point on the segment

• nextVertexIndex: Receives index of the next vertex after the closest segment. The vertex before the closest segment is always nextVertexIndex - 1

• leftOrRightOfSegment: Out: Returns if the point is located on the left or right side of the geometry ( < 0 means left, > 0 means right, 0 indicates that the test was unsuccessful, e.g. for a point exactly on the line)

closestVertex(self, point: QgsPointXY) → Tuple[QgsPointXY, int, int, int, float]

Returns the vertex closest to the given point, the corresponding vertex index, squared distance snap point / target point and the indices of the vertices before and after the closest vertex.

Parameters:

point (QgsPointXY) – point to search for

Return type:

Tuple[QgsPointXY, int, int, int, float]

Returns:

• closest point in geometry. If not found (empty geometry), returns null point and sqrDist is negative.

• closestVertexIndex: will be set to the vertex index of the closest found vertex

• previousVertexIndex: will be set to the vertex index of the previous vertex from the closest one. Will be set to -1 if not present.

• nextVertexIndex: will be set to the vertex index of the next vertex after the closest one. Will be set to -1 if not present.

• sqrDist: will be set to the square distance between the closest vertex and the specified point

closestVertexWithContext(self, point: QgsPointXY) → Tuple[float, int]

Searches for the closest vertex in this geometry to the given point.

Parameters:

point (QgsPointXY) – Specifiest the point for search

Return type:

Tuple[float, int]

Returns:

• The squared Cartesian distance is also returned in sqrDist, negative number on error

• atVertex: Receives index of the closest vertex

coerceToType(self, type: Qgis.WkbType, defaultZ: float = 0, defaultM: float = 0) → List[QgsGeometry]

Attempts to coerce this geometry into the specified destination type.

This method will do anything possible to force the current geometry into the specified type. E.g.

• lines or polygons will be converted to points by return either a single multipoint geometry or multiple single point geometries.

• polygons will be converted to lines by extracting their exterior and interior rings, returning either a multilinestring or multiple single line strings as dictated by type.

• lines will be converted to polygon rings if type is a polygon type

• curved geometries will be segmented if type is non-curved.

• multi geometries will be converted to a list of single geometries

• single geometries will be upgraded to multi geometries

• z or m values will be added or dropped as required.

Since QGIS 3.24, the parameters defaultZ and defaultM control the dimension value added when promoting geometries to Z, M or ZM versions. By default 0.0 is used for Z and M.

Note

This method is much stricter than convertToType(), as it considers the exact WKB type of geometries instead of the geometry family (point/line/polygon), and tries more exhaustively to coerce geometries to the desired type. It also correctly maintains curves and z/m values wherever appropriate.

New in version 3.14.

Parameters:

• type (Qgis.WkbType) –

• defaultZ (float = 0) –

• defaultM (float = 0) –

Return type:

List[QgsGeometry]

collectGeometry(geometries: Iterable[QgsGeometry]) → QgsGeometry

Creates a new multipart geometry from a list of QgsGeometry objects

Parameters:

geometries (Iterable[QgsGeometry]) –

Return type:

QgsGeometry

combine(self, geometry: QgsGeometry, parameters: QgsGeometryParameters = QgsGeometryParameters()) → QgsGeometry

Returns a geometry representing all the points in this geometry and other (a union geometry operation).

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Note

this operation is not called union since its a reserved word in C++.

Since QGIS 3.28 the optional parameters argument can be used to specify parameters which control the union results.

Parameters:

• geometry (QgsGeometry) –

• parameters (QgsGeometryParameters = QgsGeometryParameters()) –

Return type:

QgsGeometry

compare(obj1: object, obj2: object, epsilon: float = 4 * DBL_EPSILON) → bool

Compares two geometry objects for equality within a specified tolerance. The objects can be of type QgsPolylineXY, QgsPolygonXYor QgsMultiPolygon. The 2 types should match.

Parameters:

• p1 – first geometry object

• p2 – second geometry object

• epsilon (float = 4*DBL_EPSILON) – maximum difference for coordinates between the objects

Return type:

bool

Returns:

True if objects are

• polylines and have the same number of points and all points are equal within the specified tolerance

• polygons and have the same number of points and all points are equal within the specified tolerance

• multipolygons and have the same number of polygons, the polygons have the same number of rings, and each ring has the same number of points and all points are equal within the specified tolerance

New in version 2.9.

Parameters:

• obj1 (object) –

• obj2 (object) –

concaveHull(self, targetPercent: float, allowHoles: bool = False) → QgsGeometry

Returns a possibly concave polygon that contains all the points in the geometry.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.10 or earlier.

New in version 3.28.

Parameters:

• targetPercent (float) –

• allowHoles (bool = False) –

Return type:

QgsGeometry

constGet(self) → QgsAbstractGeometry

Returns a non-modifiable (const) reference to the underlying abstract geometry primitive.

This is much faster then calling the non-const get() method.

Note

In QGIS 2.x this method was named geometry().

See also

set()

See also

get()

New in version 3.0.

Return type:

QgsAbstractGeometry

constParts(self) → QgsGeometryConstPartIterator

Returns Java-style iterator for traversal of parts of the geometry. This iterator returns read-only references to parts and cannot be used to modify the parts.

Unlike parts(), this method does not force a detach and is more efficient if read-only iteration only is required.

Example

# print the WKT representation of each part in a multi-point geometry
geometry = QgsGeometry.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.constParts():
    print(part.asWkt())

# single part geometries only have one part - this loop will iterate once only
geometry = QgsGeometry.fromWkt( 'LineString( 0 0, 10 10 )' )
for part in geometry.constParts():
    print(part.asWkt())

# part iteration can also be combined with vertex iteration
geometry = QgsGeometry.fromWkt( 'MultiPolygon((( 0 0, 0 10, 10 10, 10 0, 0 0 ),( 5 5, 5 6, 6 6, 6 5, 5 5)),((20 2, 22 2, 22 4, 20 4, 20 2)))' )
for part in geometry.constParts():
    for v in part.vertices():
        print(v.x(), v.y())

See also

parts()

See also

vertices()

New in version 3.6.

rtype:

QgsGeometryConstPartIterator

contains(self, p: QgsPointXY) → bool

Returns True if the geometry contains the point p.

contains(self, geometry: QgsGeometry) -> bool Returns True if the geometry completely contains another geometry.

Note

For performance critical code, or when testing for contains against many different geometries, consider using QgsGeometryEngine instead. This approach can be many orders of magnitude faster than calling contains() directly. See createGeometryEngine() for details on how to use the QgsGeometryEngine class.

New in version 1.5.

Parameters:

p (QgsPointXY) –

Return type:

bool

convertGeometryCollectionToSubclass(self, geomType: Qgis.GeometryType) → bool

Converts geometry collection to a the desired geometry type subclass (multi-point, multi-linestring or multi-polygon). Child geometries of different type are filtered out. Does nothing the geometry is not a geometry collection. May leave the geometry empty if none of the child geometries match the desired type.

Return type:

bool

Returns:

True in case of success and False else

New in version 3.2.

Parameters:

geomType (Qgis.GeometryType) –

convertPointList(input: Iterable[QgsPointXY], output: Iterable[QgsPoint])

Upgrades a point list from QgsPointXY to QgsPoint

Parameters:

• input (Iterable[QgsPointXY]) – list of QgsPointXY objects to be upgraded

• output (Iterable[QgsPoint]) – destination for list of points converted to QgsPoint

convertPointList(input: Iterable[QgsPoint], output: Iterable[QgsPointXY]) Downgrades a point list from QgsPoint to QgsPointXY

Parameters:

• input – list of QgsPoint objects to be downgraded

• output – destination for list of points converted to QgsPointXY

convertToCurvedMultiType(self) → bool

Converts a geometry into a multitype geometry of curve kind (when there is a corresponding curve type). e.g. a polygon into a multisurface geometry with one polygon, a multipolygon into a multisurface, a linestring into a multicurve geometry with one linestring, or a multilinestring into a multicurve. If it is already a multipart curve geometry, it will return True and not change the geometry. It will also return True and do nothing if the current geometry is a multipoint or a geometry collection. A single point will be transformed to a multipoint.

Return type:

bool

Returns:

True in case of success and False else

New in version 3.30.

convertToCurves(self, distanceTolerance: float = 1e-08, angleTolerance: float = 1e-08) → QgsGeometry

Attempts to convert a non-curved geometry into a curved geometry type (e.g. LineString to CompoundCurve, Polygon to CurvePolygon).

The distanceTolerance specifies the maximum deviation allowed between the original location of vertices and where they would fall on the candidate curved geometry.

This method only consider a segments as suitable for replacing with an arc if the points are all regularly spaced on the candidate arc. The pointSpacingAngleTolerance parameter specifies the maximum angular deviation (in radians) allowed when testing for regular point spacing.

Note

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

New in version 3.14.

Parameters:

• distanceTolerance (float = 1e-08) –

• angleTolerance (float = 1e-08) –

Return type:

QgsGeometry

convertToMultiType(self) → bool

Converts single type geometry into multitype geometry e.g. a polygon into a multipolygon geometry with one polygon If it is already a multipart geometry, it will return True and not change the geometry.

Return type:

bool

Returns:

True in case of success and False else

convertToSingleType(self) → bool

Converts multi type geometry into single type geometry e.g. a multipolygon into a polygon geometry. Only the first part of the multi geometry will be retained. If it is already a single part geometry, it will return True and not change the geometry.

Return type:

bool

Returns:

True in case of success and False else

convertToStraightSegment(self, tolerance: float = M_PI / 180, toleranceType: QgsAbstractGeometry.SegmentationToleranceType = QgsAbstractGeometry.MaximumAngle)

Converts the geometry to straight line segments, if it is a curved geometry type.

Parameters:

• tolerance (float = M_PI/180) – segmentation tolerance

• toleranceType (QgsAbstractGeometry.SegmentationToleranceType = QgsAbstractGeometry.MaximumAngle) – maximum segmentation angle or maximum difference between approximation and curve

See also

requiresConversionToStraightSegments()

New in version 2.10.

convertToType(self, destType: Qgis.GeometryType, destMultipart: bool = False) → QgsGeometry

Try to convert the geometry to the requested type

Parameters:

• destType (Qgis.GeometryType) – the geometry type to be converted to

• destMultipart (bool = False) – determines if the output geometry will be multipart or not

Return type:

QgsGeometry

Returns:

the converted geometry or None if the conversion fails.

Note

The coerceToType() method applies much stricter and more exhaustive attempts to convert between geometry types, and is recommended instead of this method. This method force drops curves and any z or m values present in the geometry.

New in version 2.2.

convexHull(self) → QgsGeometry

Returns the smallest convex polygon that contains all the points in the geometry.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Return type:

QgsGeometry

createGeometryEngine(geometry: QgsAbstractGeometry) → QgsGeometryEngine

Creates and returns a new geometry engine representing the specified geometry.

A geometry engine is a low-level representation of a QgsAbstractGeometry object, optimised for use with external geometry libraries such as GEOS.

QgsGeometryEngine objects provide a mechanism for optimized evaluation of geometric algorithms, including spatial relationships between geometries and operations such as buffers or clipping. QgsGeometryEngine is recommended for use in any performance critical code instead of directly using the equivalent QgsGeometry methods such as QgsGeometry.intersects().

Many methods available in the QgsGeometryEngine class can benefit from pre-preparing geometries. For instance, whenever a large number of spatial relationships will be tested (such as calling intersects(), within(), etc) then the geometry should first be prepared by calling prepareGeometry() before performing the tests.

Example

# polygon_geometry contains a complex polygon, with many vertices
polygon_geometry = QgsGeometry.fromWkt('Polygon((...))')

# create a :py:class:`.QgsGeometryEngine` representation of the polygon
polygon_geometry_engine = QgsGeometry.createGeometryEngine(polygon_geometry.constGet())

# since we'll be performing many intersects tests, we can speed up these tests considerably
# by first "preparing" the geometry engine
polygon_geometry_engine.prepareGeometry()

# now we are ready to quickly test intersection against many other objects
for feature in my_layer.getFeatures():
    feature_geometry = feature.geometry()
    # test whether the feature's geometry intersects our original complex polygon
    if polygon_geometry_engine.intersects(feature_geometry.constGet()):
        print('feature intersects the polygon!')

QgsGeometryEngine operations are backed by the GEOS library (https://trac.osgeo.org/geos/).

param geometry:

type geometry:

QgsAbstractGeometry

rtype:

QgsGeometryEngine

createPolygonFromQPolygonF(polygon: QPolygonF) → object

Creates a QgsPolygonXYfrom a QPolygonF.

Parameters:

polygon (QPolygonF) – source polygon

Return type:

object

Returns:

QgsPolygon

See also

createPolylineFromQPolygonF()

Deprecated since version use: QgsGeometry.fromQPolygonF() or QgsLineString.fromQPolygonF() instead.

createPolylineFromQPolygonF(polygon: QPolygonF) → List[QgsPointXY]

Creates a QgsPolylineXY from a QPolygonF.

Parameters:

polygon (QPolygonF) – source polygon

Return type:

List[QgsPointXY]

Returns:

QgsPolylineXY

See also

createPolygonFromQPolygonF()

Deprecated since version use: QgsGeometry.fromQPolygonF() or QgsLineString.fromQPolygonF() instead.

createWedgeBuffer(center: QgsPoint, azimuth: float, angularWidth: float, outerRadius: float, innerRadius: float = 0) → QgsGeometry

Creates a wedge shaped buffer from a center point.

The azimuth gives the angle (in degrees) for the middle of the wedge to point. The buffer width (in degrees) is specified by the angularWidth parameter. Note that the wedge will extend to half of the angularWidth either side of the azimuth direction.

The outer radius of the buffer is specified via outerRadius, and optionally an innerRadius can also be specified.

The returned geometry will be a CurvePolygon geometry containing circular strings. It may need to be segmentized to convert to a standard Polygon geometry.

New in version 3.2.

Parameters:

• center (QgsPoint) –

• azimuth (float) –

• angularWidth (float) –

• outerRadius (float) –

• innerRadius (float = 0) –

Return type:

QgsGeometry

crosses(self, geometry: QgsGeometry) → bool

Returns True if the geometry crosses another geometry.

Note

For performance critical code, or when testing for crosses against many different geometries, consider using QgsGeometryEngine instead. This approach can be many orders of magnitude faster than calling crosses() directly. See createGeometryEngine() for details on how to use the QgsGeometryEngine class.

New in version 1.5.

Parameters:

geometry (QgsGeometry) –

Return type:

bool

delaunayTriangulation(self, tolerance: float = 0, edgesOnly: bool = False) → QgsGeometry

Returns the Delaunay triangulation for the vertices of the geometry. The tolerance parameter specifies an optional snapping tolerance which can be used to improve the robustness of the triangulation. If edgesOnly is True than line string boundary geometries will be returned instead of polygons. An empty geometry will be returned if the diagram could not be calculated.

New in version 3.0.

Parameters:

• tolerance (float = 0) –

• edgesOnly (bool = False) –

Return type:

QgsGeometry

deletePart(self, partNum: int) → bool

Deletes part identified by the part number

Return type:

bool

Returns:

True on success

New in version 1.2.

Parameters:

partNum (int) –

deleteRing(self, ringNum: int, partNum: int = 0) → bool

Deletes a ring in polygon or multipolygon. Ring 0 is outer ring and can’t be deleted.

Return type:

bool

Returns:

True on success

New in version 1.2.

Parameters:

• ringNum (int) –

• partNum (int = 0) –

deleteVertex(self, atVertex: int) → bool

Deletes the vertex at the given position number and item (first number is index 0)

Return type:

bool

Returns:

False if atVertex does not correspond to a valid vertex on this geometry (including if this geometry is a Point), or if the number of remaining vertices in the linestring would be less than two. It is up to the caller to distinguish between these error conditions. (Or maybe we add another method to this object to help make the distinction?)

Parameters:

atVertex (int) –

densifyByCount(self, extraNodesPerSegment: int) → QgsGeometry

Returns a copy of the geometry which has been densified by adding the specified number of extra nodes within each segment of the geometry. If the geometry has z or m values present then these will be linearly interpolated at the added nodes. Curved geometry types are automatically segmentized by this routine.

See also

densifyByDistance()

New in version 3.0.

Parameters:

extraNodesPerSegment (int) –

Return type:

QgsGeometry

densifyByDistance(self, distance: float) → QgsGeometry

Densifies the geometry by adding regularly placed extra nodes inside each segment so that the maximum distance between any two nodes does not exceed the specified distance. E.g. specifying a distance 3 would cause the segment [0 0] -> [10 0] to be converted to [0 0] -> [2.5 0] -> [5 0] -> [7.5 0] -> [10 0], since 3 extra nodes are required on the segment and spacing these at 2.5 increments allows them to be evenly spaced over the segment. If the geometry has z or m values present then these will be linearly interpolated at the added nodes. Curved geometry types are automatically segmentized by this routine.

See also

densifyByCount()

New in version 3.0.

Parameters:

distance (float) –

Return type:

QgsGeometry

difference(self, geometry: QgsGeometry, parameters: QgsGeometryParameters = QgsGeometryParameters()) → QgsGeometry

Returns a geometry representing the points making up this geometry that do not make up other.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Since QGIS 3.28 the optional parameters argument can be used to specify parameters which control the difference results.

Parameters:

• geometry (QgsGeometry) –

• parameters (QgsGeometryParameters = QgsGeometryParameters()) –

Return type:

QgsGeometry

disjoint(self, geometry: QgsGeometry) → bool

Returns True if the geometry is disjoint of another geometry.

Note

For performance critical code, or when testing for disjoint against many different geometries, consider using QgsGeometryEngine instead. This approach can be many orders of magnitude faster than calling disjoint() directly. See createGeometryEngine() for details on how to use the QgsGeometryEngine class.

New in version 1.5.

Parameters:

geometry (QgsGeometry) –

Return type:

bool

distance(self, geom: QgsGeometry) → float

Returns the minimum distance between this geometry and another geometry. Will return a negative value if either geometry is empty or null.

Warning

QgsGeometry objects are inherently Cartesian/planar geometries, and the distance returned by this method is calculated using strictly Cartesian mathematics.

Parameters:

geom (QgsGeometry) –

Return type:

float

distanceToVertex(self, vertex: int) → float

Returns the distance along this geometry from its first vertex to the specified vertex.

Parameters:

vertex (int) – vertex index to calculate distance to

Return type:

float

Returns:

distance to vertex (following geometry), or -1 for invalid vertex numbers

Warning

QgsGeometry objects are inherently Cartesian/planar geometries, and the distance returned by this method is calculated using strictly Cartesian mathematics.

New in version 2.16.

draw(self, p: QPainter)

Draws the geometry onto a QPainter

Parameters:

p (QPainter) – destination QPainter

New in version 2.10.

equals(self, geometry: QgsGeometry) → bool

Test if this geometry is exactly equal to another geometry.

This is a strict equality check, where the underlying geometries must have exactly the same type, component vertices and vertex order.

Calling this method is dramatically faster than the topological equality test performed by isGeosEqual().

Note

Comparing two null geometries will return False.

See also

isGeosEqual()

New in version 1.5.

Parameters:

geometry (QgsGeometry) –

Return type:

bool

extendLine(self, startDistance: float, endDistance: float) → QgsGeometry

Extends a (multi)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.

New in version 3.0.

Parameters:

• startDistance (float) –

• endDistance (float) –

Return type:

QgsGeometry

extrude(self, x: float, y: float) → QgsGeometry

Returns an extruded version of this geometry.

Parameters:

• x (float) –

• y (float) –

Return type:

QgsGeometry

forcePolygonClockwise(self) → QgsGeometry

Forces geometries to respect the exterior ring is clockwise, interior rings are counter-clockwise convention.

This convention is used primarily by ESRI software.

See also

isPolygonClockwise()

See also

isPolygonCounterClockwise()

See also

forcePolygonCounterClockwise()

New in version 3.24.

Return type:

QgsGeometry

forcePolygonCounterClockwise(self) → QgsGeometry

Forces geometries to respect the exterior ring is counter-clockwise, interior rings are clockwise convention.

This convention matches the OGC Simple Features specification.

See also

isPolygonClockwise()

See also

isPolygonCounterClockwise()

See also

forcePolygonClockwise()

New in version 3.24.

Return type:

QgsGeometry

forceRHR(self) → QgsGeometry

Forces geometries to respect the Right-Hand-Rule, in which the area that is bounded by a polygon is to the right of the boundary. In particular, the exterior ring is oriented in a clockwise direction and the interior rings in a counter-clockwise direction.

Warning

Due to the conflicting definitions of the right-hand-rule in general use, it is recommended to use the explicit forcePolygonClockwise() or forcePolygonCounterClockwise() methods instead.

See also

isPolygonClockwise()

See also

isPolygonCounterClockwise()

See also

forcePolygonClockwise()

See also

forcePolygonCounterClockwise()

New in version 3.6.

Return type:

QgsGeometry

frechetDistance(self, geom: QgsGeometry) → float

Returns the Fréchet distance between this geometry and geom, restricted to discrete points for both geometries.

The Fréchet distance is a measure of similarity between curves that takes into account the location and ordering of the points along the curves. Therefore it is often better than the Hausdorff distance.

In case of error -1 will be returned.

This method requires a QGIS build based on GEOS 3.7 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.6 or earlier.

See also

frechetDistanceDensify()

New in version 3.20.

Parameters:

geom (QgsGeometry) –

Return type:

float

frechetDistanceDensify(self, geom: QgsGeometry, densifyFraction: float) → float

Returns the Fréchet distance between this geometry and geom, restricted to discrete points for both geometries.

The Fréchet distance is a measure of similarity between curves that takes into account the location and ordering of the points along the curves. Therefore it is often better than the Hausdorff distance.

This function accepts a densifyFraction argument. The function performs a segment densification before computing the discrete Fréchet distance. The densifyFraction parameter sets the fraction by which to densify each segment. Each segment will be split into a number of equal-length subsegments, whose fraction of the total length is closest to the given fraction.

This method can be used when the default approximation provided by frechetDistance() is not sufficient. Decreasing the densifyFraction parameter will make the distance returned approach the true Fréchet distance for the geometries.

This method requires a QGIS build based on GEOS 3.7 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.6 or earlier.

See also

frechetDistance()

New in version 3.20.

Parameters:

• geom (QgsGeometry) –

• densifyFraction (float) –

Return type:

float

fromBox3D(box: QgsBox3D) → QgsGeometry

Creates a new geometry from a QgsBox3D object

New in version 3.34.

Parameters:

box (QgsBox3D) –

Return type:

QgsGeometry

fromMultiPointXY(multipoint: Iterable[QgsPointXY]) → QgsGeometry

Creates a new geometry from a QgsMultiPointXY object

Parameters:

multipoint (Iterable[QgsPointXY]) –

Return type:

QgsGeometry

fromMultiPolygonXY(multipoly: object) → QgsGeometry

Creates a new geometry from a QgsMultiPolygonXY.

Parameters:

multipoly (object) –

Return type:

QgsGeometry

fromMultiPolylineXY(multiline: object) → QgsGeometry

Creates a new geometry from a QgsMultiPolylineXY object.

Parameters:

multiline (object) –

Return type:

QgsGeometry

fromPoint(point: QgsPoint) → QgsGeometry

Creates a new geometry from a QgsPoint object.

New in version 3.34.

Parameters:

point (QgsPoint) –

Return type:

QgsGeometry

fromPointXY(point: QgsPointXY) → QgsGeometry

Creates a new geometry from a QgsPointXY object

Parameters:

point (QgsPointXY) –

Return type:

QgsGeometry

fromPolygonXY(polygon: object) → QgsGeometry

Creates a new polygon geometry from a list of lists of QgsPointXY.

The first list of QgsPointXY objects specifies the exterior ring of the polygon, and the remaining lists specify any interior rings.

Example

# Create a polygon geometry with a single exterior ring (a triangle)
polygon = QgsGeometry.fromPolygonXY([[QgsPointXY(1, 2), QgsPointXY(5, 2), QgsPointXY(5, 10), QgsPointXY(1, 2)]]))

# Create a donut shaped polygon geometry with an interior ring
polygon = QgsGeometry.fromPolygonXY([[QgsPointXY(1, 2), QgsPointXY(5, 2), QgsPointXY(5, 10), QgsPointXY(1, 10), QgsPointXY(1, 2)],
                                     [QgsPointXY(3, 4), QgsPointXY(4, 4), QgsPointXY(4, 6), QgsPointXY(3, 6), QgsPointXY(3, 4)]])

param polygon:

type polygon:

object

rtype:

QgsGeometry

fromPolyline(polyline: Iterable[QgsPoint]) → QgsGeometry

Creates a new LineString geometry from a list of QgsPoint points.

This method will respect any Z or M dimensions present in the input points. E.g. if input points are PointZ type, the resultant linestring will be a LineStringZ type.

New in version 3.0.

Parameters:

polyline (Iterable[QgsPoint]) –

Return type:

QgsGeometry

fromPolylineXY(polyline: Iterable[QgsPointXY]) → QgsGeometry

Creates a new LineString geometry from a list of QgsPointXY points.

Using fromPolyline() is preferred, as fromPolyline() is more efficient and will respect any Z or M dimensions present in the input points.

Note

In QGIS 2.x this method was available as fromPolyline().

See also

fromPolyline()

New in version 3.0.

Parameters:

polyline (Iterable[QgsPointXY]) –

Return type:

QgsGeometry

fromQPointF(point: QPointF | QPoint | float) → QgsGeometry

Construct geometry from a QPointF

Parameters:

point (Union[QPointF) – source QPointF

New in version 2.7.

Return type:

QgsGeometry

fromQPolygonF(polygon: QPolygonF) → QgsGeometry

Construct geometry from a QPolygonF. If the polygon is closed than the resultant geometry will be a polygon, if it is open than the geometry will be a polyline.

Parameters:

polygon (QPolygonF) – source QPolygonF

New in version 2.7.

Return type:

QgsGeometry

fromRect(rect: QgsRectangle) → QgsGeometry

Creates a new geometry from a QgsRectangle

Parameters:

rect (QgsRectangle) –

Return type:

QgsGeometry

fromWkb(self, wkb: QByteArray | bytes | bytearray)

Set the geometry, feeding in the buffer containing OGC Well-Known Binary

New in version 3.0.

Parameters:

wkb (Union[QByteArray) –

fromWkt(wkt: str) → QgsGeometry

Creates a new geometry from a WKT string

Parameters:

wkt (str) –

Return type:

QgsGeometry

get(self) → QgsAbstractGeometry

Returns a modifiable (non-const) reference to the underlying abstract geometry primitive.

This method can be slow to call, as it may trigger a detachment of the geometry and a deep copy. Where possible, use constGet() instead.

Note

In QGIS 2.x this method was named geometry().

See also

constGet()

See also

set()

New in version 3.0.

Return type:

QgsAbstractGeometry

hausdorffDistance(self, geom: QgsGeometry) → float

Returns the Hausdorff distance between this geometry and geom. This is basically a measure of how similar or dissimilar 2 geometries are.

This algorithm is an approximation to the standard Hausdorff distance. This approximation is exact or close enough for a large subset of useful cases. Examples of these are:

• computing distance between Linestrings that are roughly parallel to each other, and roughly equal in length. This occurs in matching linear networks.

• Testing similarity of geometries.

If the default approximate provided by this method is insufficient, use hausdorffDistanceDensify() instead.

In case of error -1 will be returned.

See also

hausdorffDistanceDensify()

New in version 3.0.

Parameters:

geom (QgsGeometry) –

Return type:

float

hausdorffDistanceDensify(self, geom: QgsGeometry, densifyFraction: float) → float

Returns the Hausdorff distance between this geometry and geom. This is basically a measure of how similar or dissimilar 2 geometries are.

This function accepts a densifyFraction argument. The function performs a segment densification before computing the discrete Hausdorff distance. The densifyFraction parameter sets the fraction by which to densify each segment. Each segment will be split into a number of equal-length subsegments, whose fraction of the total length is closest to the given fraction.

This method can be used when the default approximation provided by hausdorffDistance() is not sufficient. Decreasing the densifyFraction parameter will make the distance returned approach the true Hausdorff distance for the geometries.

In case of error -1 will be returned.

See also

hausdorffDistance()

New in version 3.0.

Parameters:

• geom (QgsGeometry) –

• densifyFraction (float) –

Return type:

float

insertVertex(self, x: float, y: float, beforeVertex: int) → bool

Insert a new vertex before the given vertex index, ring and item (first number is index 0) If the requested vertex number (beforeVertex.back()) is greater than the last actual vertex on the requested ring and item, it is assumed that the vertex is to be appended instead of inserted. Returns False if atVertex does not correspond to a valid vertex on this geometry (including if this geometry is a Point). It is up to the caller to distinguish between these error conditions. (Or maybe we add another method to this object to help make the distinction?)

insertVertex(self, point: QgsPoint, beforeVertex: int) -> bool Insert a new vertex before the given vertex index, ring and item (first number is index 0) If the requested vertex number (beforeVertex.back()) is greater than the last actual vertex on the requested ring and item, it is assumed that the vertex is to be appended instead of inserted. Returns False if atVertex does not correspond to a valid vertex on this geometry (including if this geometry is a Point). It is up to the caller to distinguish between these error conditions. (Or maybe we add another method to this object to help make the distinction?)

Parameters:

• x (float) –

• y (float) –

• beforeVertex (int) –

Return type:

bool

interpolate(self, distance: float) → QgsGeometry

Returns an interpolated point on the geometry at the specified distance.

If the original geometry is a polygon type, the boundary of the polygon will be used during interpolation. If the original geometry is a point type, a null geometry will be returned.

If z or m values are present, the output z and m will be interpolated using the existing vertices’ z or m values.

If the input is a NULL geometry, the output will also be a NULL geometry.

See also

lineLocatePoint()

New in version 2.0.

Parameters:

distance (float) –

Return type:

QgsGeometry

interpolateAngle(self, distance: float) → float

Returns the angle parallel to the linestring or polygon boundary at the specified distance along the geometry. Angles are in radians, clockwise from north. If the distance coincides precisely at a node then the average angle from the segment either side of the node is returned.

Parameters:

distance (float) – distance along geometry

See also

angleAtVertex()

New in version 3.0.

Return type:

float

intersection(self, geometry: QgsGeometry, parameters: QgsGeometryParameters = QgsGeometryParameters()) → QgsGeometry

Returns a geometry representing the points shared by this geometry and other.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Since QGIS 3.28 the optional parameters argument can be used to specify parameters which control the intersection results.

Parameters:

• geometry (QgsGeometry) –

• parameters (QgsGeometryParameters = QgsGeometryParameters()) –

Return type:

QgsGeometry

intersects(self, rectangle: QgsRectangle) → bool

Returns True if this geometry exactly intersects with a rectangle. This test is exact and can be slow for complex geometries.

The GEOS library is used to perform the intersection test. Geometries which are not valid may return incorrect results.

See also

boundingBoxIntersects()

intersects(self, geometry: QgsGeometry) -> bool Returns True if this geometry exactly intersects with another geometry. This test is exact and can be slow for complex geometries.

The GEOS library is used to perform the intersection test. Geometries which are not valid may return incorrect results.

Note

For performance critical code, or when testing for intersection against many different geometries, consider using QgsGeometryEngine instead. This approach can be many orders of magnitude faster than calling intersects() directly. See createGeometryEngine() for details on how to use the QgsGeometryEngine class.

See also

boundingBoxIntersects()

Parameters:

rectangle (QgsRectangle) –

Return type:

bool

isAxisParallelRectangle(self, maximumDeviation: float, simpleRectanglesOnly: bool = False) → bool

Returns True if the geometry is a polygon that is almost an axis-parallel rectangle.

The maximumDeviation argument specifes the maximum angle (in degrees) that the polygon edges are allowed to deviate from axis parallel lines.

By default the check will permit polygons with more than 4 edges, so long as the overall shape of the polygon is an axis-parallel rectangle (i.e. it is tolerant to rectangles with additional vertices added along the rectangle sides). If simpleRectanglesOnly is set to True then the method will only return True if the geometry is a simple rectangle consisting of 4 edges.

New in version 3.20.

Parameters:

• maximumDeviation (float) –

• simpleRectanglesOnly (bool = False) –

Return type:

bool

isEmpty(self) → bool

Returns True if the geometry is empty (eg a linestring with no vertices, or a collection with no geometries). A null geometry will always return True for isEmpty().

See also

isNull()

Return type:

bool

isGeosEqual(self, QgsGeometry) → bool

Compares the geometry with another geometry using GEOS.

This method performs a slow, topological check, where geometries are considered equal if all of the their component edges overlap. E.g. lines with the same vertex locations but opposite direction will be considered equal by this method.

Consider using the much faster, stricter equality test performed by equals() instead.

Note

Comparing two null geometries will return False.

See also

equals()

New in version 1.5.

Return type:

bool

isGeosValid(self, flags: Qgis.GeometryValidityFlags | Qgis.GeometryValidityFlag = Qgis.GeometryValidityFlags()) → bool

Checks validity of the geometry using GEOS.

The flags parameter indicates optional flags which control the type of validity checking performed.

New in version 1.5.

Parameters:

flags (Union[Qgis.GeometryValidityFlags) –

Return type:

bool

isMultipart(self) → bool

Returns True if WKB of the geometry is of WKBMulti* type

Return type:

bool

isNull(self) → bool

Returns True if the geometry is null (ie, contains no underlying geometry accessible via get() or constGet() ).

See also

get()

See also

constGet()

See also

isEmpty()

New in version 2.10.

Return type:

bool

isPolygonClockwise(self) → bool

Returns True if the Polygon is clockwise.

Warning

Only the first exterior ring is taken to perform this operation. In case of degenerate orders, you have to perform in deep verification.

Warning

returns true if the geometry is not a polygon type or empty

See also

isPolygonCounterClockwise()

See also

forcePolygonClockwise()

See also

forcePolygonCounterClockwise()

New in version 3.36.

Return type:

bool

isPolygonCounterClockwise(self) → bool

Returns True if the Polygon is counter-clockwise.

Warning

Only the first exterior ring is taken to perform this operation. In case of degenerate orders, you have to perform in deep verification.

Warning

returns false if the geometry is not a polygon type or empty

See also

isPolygonClockwise()

See also

forcePolygonClockwise()

See also

forcePolygonCounterClockwise()

New in version 3.36.

Return type:

bool

isSimple(self) → bool

Determines whether the geometry is simple (according to OGC definition), i.e. it has no anomalous geometric points, such as self-intersection or self-tangency. Uses GEOS library for the test.

Note

This is useful mainly for linestrings and linear rings. Polygons are simple by definition, for checking anomalies in polygon geometries one can use isGeosValid().

New in version 3.0.

Return type:

bool

largestEmptyCircle(self, tolerance: float, boundary: QgsGeometry = QgsGeometry()) → QgsGeometry

Constructs the Largest Empty Circle for a set of obstacle geometries, up to a specified tolerance.

The Largest Empty Circle is the largest circle which has its center in the convex hull of the obstacles (the boundary), and whose interior does not intersect with any obstacle. The circle center is the point in the interior of the boundary which has the farthest distance from the obstacles (up to tolerance). The circle is determined by the center point and a point lying on an obstacle indicating the circle radius. The implementation uses a successive-approximation technique over a grid of square cells covering the obstacles and boundary. The grid is refined using a branch-and-bound algorithm. Point containment and distance are computed in a performant way by using spatial indexes. Returns a two-point linestring, with one point at the center of the inscribed circle and the other on the boundary of the inscribed circle.

This method requires QGIS builds based on GEOS 3.9 or later.

Warning

the tolerance value must be a value greater than 0, or the algorithm may never converge on a solution

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.8 or earlier.

New in version 3.20.

Parameters:

• tolerance (float) –

• boundary (QgsGeometry = QgsGeometry()) –

Return type:

QgsGeometry

lastError(self) → str

Returns an error string referring to the last error encountered either when this geometry was created or when an operation was performed on the geometry.

New in version 3.0.

Return type:

str

length(self) → float

Returns the planar, 2-dimensional length of geometry.

If the geometry is a polygon geometry then the perimeter of the polygon will be returned.

Warning

QgsGeometry objects are inherently Cartesian/planar geometries, and the length returned by this method is calculated using strictly Cartesian mathematics. In contrast, the QgsDistanceArea class exposes methods for calculating the lengths of geometries using geodesic calculations which account for the curvature of the Earth (or any other celestial body).

See also

area()

New in version 1.5.

Return type:

float

lineLocatePoint(self, point: QgsGeometry) → float

Returns a distance representing the location along this linestring of the closest point on this linestring geometry to the specified point. Ie, the returned value indicates how far along this linestring you need to traverse to get to the closest location where this linestring comes to the specified point.

Parameters:

point (QgsGeometry) – point to seek proximity to

Return type:

float

Returns:

distance along line, or -1 on error

Note

only valid for linestring geometries

See also

interpolate()

New in version 3.0.

makeDifference(self, other: QgsGeometry) → QgsGeometry

Returns the geometry formed by modifying this geometry such that it does not intersect the other geometry.

Parameters:

other (QgsGeometry) – geometry that should not be intersect

Return type:

QgsGeometry

Returns:

difference geometry, or empty geometry if difference could not be calculated

New in version 3.0.

makeValid(self, method: Qgis.MakeValidMethod = Qgis.MakeValidMethod.Linework, keepCollapsed: bool = False) → QgsGeometry

Attempts to make an invalid geometry valid without losing vertices.

Already-valid geometries are returned without further intervention. In case of full or partial dimensional collapses, the output geometry may be a collection of lower-to-equal dimension geometries or a geometry of lower dimension. Single polygons may become multi-geometries in case of self-intersections. It preserves Z values, but M values will be dropped.

If an error was encountered during the process, more information can be retrieved by calling lastError() on the returned geometry.

The method and keepCollapsed arguments are available since QGIS 3.28. They require builds based on GEOS 3.10 or later.

Return type:

QgsGeometry

Returns:

new valid QgsGeometry or null geometry on error

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.9 or earlier when the method is not Qgis.MakeValidMethod.Linework or the keepCollapsed option is set.

New in version 3.0.

Parameters:

• method (Qgis.MakeValidMethod = Qgis.MakeValidMethod.Linework) –

• keepCollapsed (bool = False) –

mapToPixel(self, mtp: QgsMapToPixel)

Transforms the geometry from map units to pixels in place.

Parameters:

mtp (QgsMapToPixel) – map to pixel transform

New in version 2.10.

mergeLines(self) → QgsGeometry

Merges any connected lines in a LineString/MultiLineString geometry and converts them to single line strings.

Return type:

QgsGeometry

Returns:

a LineString or MultiLineString geometry, with any connected lines joined. An empty geometry will be returned if the input geometry was not a MultiLineString geometry.

New in version 3.0.

minimalEnclosingCircle(self, segments: int = 36) → Tuple[QgsGeometry, QgsPointXY, float]

Returns the minimal enclosing circle for the geometry.

Parameters:

segments (int = 36) – Number of segments used to segment geometry. QgsEllipse.toPolygon()

Return type:

Tuple[QgsGeometry, QgsPointXY, float]

Returns:

• the minimal enclosing circle as a QGIS geometry

• center: Center of the minimal enclosing circle returneds

• radius: Radius of the minimal enclosing circle returned

New in version 3.0.

minimumClearance(self) → float

Computes the minimum clearance of a geometry.

The minimum clearance is the smallest amount by which a vertex could be moved to produce an invalid polygon, a non-simple linestring, or a multipoint with repeated points. If a geometry has a minimum clearance of ‘eps’, it can be said that:

• No two distinct vertices in the geometry are separated by less than ‘eps’

• No vertex is closer than ‘eps’ to a line segment of which it is not an endpoint.

If the minimum clearance cannot be defined for a geometry (such as with a single point, or a multipoint whose points are identical) a value of infinity will be returned.

If an error occurs while calculating the clearance NaN will be returned.

This method requires a QGIS build based on GEOS 3.6 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.5 or earlier.

New in version 3.20.

Return type:

float

minimumClearanceLine(self) → QgsGeometry

Returns a LineString whose endpoints define the minimum clearance of a geometry.

If the geometry has no minimum clearance, an empty LineString will be returned.

This method requires a QGIS build based on GEOS 3.6 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.5 or earlier.

New in version 3.20.

Return type:

QgsGeometry

minimumWidth(self) → QgsGeometry

Returns a linestring geometry which represents the minimum diameter of the geometry.

The minimum diameter is defined to be the width of the smallest band that contains the geometry, where a band is a strip of the plane defined by two parallel lines. This can be thought of as the smallest hole that the geometry can be moved through, with a single rotation.

This method requires a QGIS build based on GEOS 3.6 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.5 or earlier.

New in version 3.20.

Return type:

QgsGeometry

moveVertex(self, x: float, y: float, atVertex: int) → bool

Moves the vertex at the given position number and item (first number is index 0) to the given coordinates. Returns False if atVertex does not correspond to a valid vertex on this geometry

moveVertex(self, p: QgsPoint, atVertex: int) -> bool Moves the vertex at the given position number and item (first number is index 0) to the given coordinates. Returns False if atVertex does not correspond to a valid vertex on this geometry

Parameters:

• x (float) –

• y (float) –

• atVertex (int) –

Return type:

bool

nearestPoint(self, other: QgsGeometry) → QgsGeometry

Returns the nearest (closest) point on this geometry to another geometry.

See also

shortestLine()

New in version 2.14.

Parameters:

other (QgsGeometry) –

Return type:

QgsGeometry

node(self) → QgsGeometry

Returns a (Multi)LineString representing the fully noded version of a collection of linestrings.

The noding preserves all of the input nodes, and introduces the least possible number of new nodes. The resulting linework is dissolved (duplicate lines are removed).

The input geometry type should be a (Multi)LineString.

New in version 3.20.

Return type:

QgsGeometry

normalize(self)

Reorganizes the geometry into a normalized form (or “canonical” form).

Polygon rings will be rearranged so that their starting vertex is the lower left and ring orientation follows the right hand rule, collections are ordered by geometry type, and other normalization techniques are applied. The resultant geometry will be geometrically equivalent to the original geometry.

New in version 3.20.

offsetCurve(self, distance: float, segments: int, joinStyle: Qgis.JoinStyle, miterLimit: float) → QgsGeometry

Returns an offset line at a given distance and side from an input line.

Parameters:

• distance (float) – buffer distance

• segments (int) – for round joins, number of segments to approximate quarter-circle

• joinStyle (Qgis.JoinStyle) – join style for corners in geometry

• miterLimit (float) – limit on the miter ratio used for very sharp corners (JoinStyleMiter only)

New in version 2.4.

Return type:

QgsGeometry

orientedMinimumBoundingBox(self) → Tuple[QgsGeometry, float, float, float, float]

Returns the oriented minimum bounding box for the geometry, which is the smallest (by area) rotated rectangle which fully encompasses the geometry. The area, angle (clockwise in degrees from North), width and height of the rotated bounding box will also be returned.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

See also

boundingBox()

New in version 3.0.

Return type:

Tuple[QgsGeometry, float, float, float, float]

orthogonalize(self, tolerance: float = 1e-08, maxIterations: int = 1000, angleThreshold: float = 15) → QgsGeometry

Attempts to orthogonalize a line or polygon geometry by shifting vertices to make the geometries angles either right angles or flat lines. This is an iterative algorithm which will loop until either the vertices are within a specified tolerance of right angles or a set number of maximum iterations is reached. The angle threshold parameter specifies how close to a right angle or straight line an angle must be before it is attempted to be straightened.

New in version 3.0.

Parameters:

• tolerance (float = 1e-08) –

• maxIterations (int = 1000) –

• angleThreshold (float = 15) –

Return type:

QgsGeometry

overlaps(self, geometry: QgsGeometry) → bool

Returns True if the geometry overlaps another geometry.

Note

For performance critical code, or when testing for overlaps against many different geometries, consider using QgsGeometryEngine instead. This approach can be many orders of magnitude faster than calling overlaps() directly. See createGeometryEngine() for details on how to use the QgsGeometryEngine class.

New in version 1.5.

Parameters:

geometry (QgsGeometry) –

Return type:

bool

parts(self) → QgsGeometryPartIterator

Returns Java-style iterator for traversal of parts of the geometry. This iterator can safely be used to modify parts of the geometry.

This method forces a detach. Use constParts() to avoid the detach if the parts are not going to be modified.

Example

# print the WKT representation of each part in a multi-point geometry
geometry = QgsGeometry.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.parts():
    print(part.asWkt())

# single part geometries only have one part - this loop will iterate once only
geometry = QgsGeometry.fromWkt( 'LineString( 0 0, 10 10 )' )
for part in geometry.parts():
    print(part.asWkt())

# parts can be modified during the iteration
geometry = QgsGeometry.fromWkt( 'MultiPoint( 0 0, 1 1, 2 2)' )
for part in geometry.parts():
    part.transform(ct)

# part iteration can also be combined with vertex iteration
geometry = QgsGeometry.fromWkt( 'MultiPolygon((( 0 0, 0 10, 10 10, 10 0, 0 0 ),( 5 5, 5 6, 6 6, 6 5, 5 5)),((20 2, 22 2, 22 4, 20 4, 20 2)))' )
for part in geometry.parts():
    for v in part.vertices():
        print(v.x(), v.y())

See also

constParts()

See also

vertices()

New in version 3.6.

rtype:

QgsGeometryPartIterator

pointOnSurface(self) → QgsGeometry

Returns a point guaranteed to lie on the surface of a geometry. While the centroid() of a geometry may be located outside of the geometry itself (e.g., for concave shapes), the point on surface will always be inside the geometry.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

See also

centroid()

See also

poleOfInaccessibility()

Return type:

QgsGeometry

poleOfInaccessibility(self, precision: float) → Tuple[QgsGeometry, float]

Calculates the approximate pole of inaccessibility for a surface, which is the most distant internal point from the boundary of the surface. This function uses the ‘polylabel’ algorithm (Vladimir Agafonkin, 2016), which is an iterative approach guaranteed to find the true pole of inaccessibility within a specified tolerance. More precise tolerances require more iterations and will take longer to calculate. Optionally, the distance to the polygon boundary from the pole can be stored.

See also

centroid()

See also

pointOnSurface()

New in version 3.0.

Parameters:

precision (float) –

Return type:

Tuple[QgsGeometry, float]

polygonOrientation(self) → Qgis.AngularDirection

Returns the orientation of the polygon.

Warning

Only the first exterior ring is taken to perform this operation. In case of degenerate orders, you have to perform in deep verification.

Warning

returns Qgis.AngularDirection.NoOrientation if the geometry is not a polygon type or empty

New in version 3.36.

Return type:

Qgis.AngularDirection

polygonize(geometries: Iterable[QgsGeometry]) → QgsGeometry

Creates a GeometryCollection geometry containing possible polygons formed from the constituent linework of a set of geometries. The input geometries must be fully noded (i.e. nodes exist at every common intersection of the geometries). The easiest way to ensure this is to first call unaryUnion() on the set of input geometries and then pass the result to polygonize(). An empty geometry will be returned in the case of errors.

New in version 3.0.

Parameters:

geometries (Iterable[QgsGeometry]) –

Return type:

QgsGeometry

randomPointsInPolygon(self, count: int, seed: int = 0) → QgsPolylineXY

Returns a list of count random points generated inside a (multi)polygon geometry.

Optionally, a specific random seed can be used when generating points. If seed is 0, then a completely random sequence of points will be generated.

This method works only with (multi)polygon geometry types.

Raises:

• TypeError – if the geometry is not a polygon type

• ValueError – if the geometry is null

New in version 3.10.

Parameters:

• count (int) –

• seed (int = 0) –

Return type:

QgsPolylineXY

removeDuplicateNodes(self, epsilon: float = 4 * DBL_EPSILON, useZValues: bool = False) → bool

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.

New in version 3.0.

Parameters:

• epsilon (float = 4*DBL_EPSILON) –

• useZValues (bool = False) –

Return type:

bool

removeInteriorRings(self, minimumAllowedArea: float = -1) → QgsGeometry

Removes the interior rings from a (multi)polygon geometry. If the minimumAllowedArea parameter is specified then only rings smaller than this minimum area will be removed.

New in version 3.0.

Parameters:

minimumAllowedArea (float = -1) –

Return type:

QgsGeometry

requiresConversionToStraightSegments(self) → bool

Returns True if the geometry is a curved geometry type which requires conversion to display as straight line segments.

See also

convertToStraightSegment()

New in version 2.10.

Return type:

bool

reshapeGeometry(self, reshapeLineString: QgsLineString) → Qgis.GeometryOperationResult

Replaces a part of this geometry with another line

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

Parameters:

reshapeLineString (QgsLineString) –

rotate(self, rotation: float, center: QgsPointXY) → Qgis.GeometryOperationResult

Rotate this geometry around the Z axis

Parameters:

• rotation (float) – clockwise rotation in degrees

• center (QgsPointXY) – rotation center

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

roundWaves(self, wavelength: float, amplitude: float, strictWavelength: bool = False) → QgsGeometry

Constructs rounded (sine-like) waves along the boundary of the geometry, with the specified wavelength and amplitude.

By default the wavelength argument is treated as a “maximum wavelength”, where the actual wavelength will be dynamically adjusted so that an exact number of waves are created along the boundaries of the geometry. If strictWavelength is set to True then the wavelength will be used exactly and an incomplete pattern may be used for the final waveform.

See also

roundWavesRandomized()

New in version 3.24.

Parameters:

• wavelength (float) –

• amplitude (float) –

• strictWavelength (bool = False) –

Return type:

QgsGeometry

roundWavesRandomized(self, minimumWavelength: float, maximumWavelength: float, minimumAmplitude: float, maximumAmplitude: float, seed: int = 0) → QgsGeometry

Constructs randomized rounded (sine-like) waves along the boundary of the geometry, with the specified wavelength and amplitude ranges.

The minimumWavelength and maximumWavelength arguments set the range for the randomized wavelength. This is evaluated for each individual waveform created along the geometry boundaries, so the resultant geometry will consist of many different wavelengths.

Similarly, the minimumAmplitude and maximumAmplitude arguments define the range for the randomized amplitude of the square components. Randomized amplitude values will be calculated individually for waves placed on each either side of the input geometry boundaries.

Optionally, a specific random seed can be used when generating points. If seed is 0, then a completely random sequence of points will be generated.

See also

squareWaves()

New in version 3.24.

Parameters:

• minimumWavelength (float) –

• maximumWavelength (float) –

• minimumAmplitude (float) –

• maximumAmplitude (float) –

• seed (int = 0) –

Return type:

QgsGeometry

set(self, geometry: QgsAbstractGeometry)

Sets the underlying geometry store. Ownership of geometry is transferred.

Note

In QGIS 2.x this method was named setGeometry().

Note

This method is deprecated for usage in Python and will be removed from Python bindings with QGIS 4. Using this method will confuse Python’s memory management and type information system. Better create a new QgsGeometry object instead.

See also

get()

See also

constGet()

New in version 3.0.

Parameters:

geometry (QgsAbstractGeometry) –

sharedPaths(self, other: QgsGeometry) → QgsGeometry

Find paths shared between the two given lineal geometries (this and other).

Returns a GeometryCollection having two elements:

• first element is a MultiLineString containing shared paths having the same direction on both inputs

• second element is a MultiLineString containing shared paths having the opposite direction on the two inputs

Returns a null geometry on exception.

New in version 3.20.

Parameters:

other (QgsGeometry) –

Return type:

QgsGeometry

shortestLine(self, other: QgsGeometry) → QgsGeometry

Returns the shortest line joining this geometry to another geometry.

See also

nearestPoint()

Warning

QgsGeometry objects are inherently Cartesian/planar geometries, and the line returned by this method is calculated using strictly Cartesian mathematics. See QgsDistanceArea for similar methods which account for the curvature of an ellipsoidal body such as the Earth.

New in version 2.14.

Parameters:

other (QgsGeometry) –

Return type:

QgsGeometry

simplify(self, tolerance: float) → QgsGeometry

Returns a simplified version of this geometry using a specified tolerance value

Parameters:

tolerance (float) –

Return type:

QgsGeometry

simplifyCoverageVW(self, tolerance: float, preserveBoundary: bool) → QgsGeometry

Operates on a coverage (represented as a list of polygonal geometry with exactly matching edge geometry) to apply a Visvalingam–Whyatt simplification to the edges, reducing complexity in proportion with the provided tolerance, while retaining a valid coverage (no edges will cross or touch after the simplification).

Geometries never disappear, but they may be simplified down to just a triangle. Also, some invalid geoms (such as Polygons which have too few non-repeated points) will be returned unchanged.

If the input dataset is not a valid coverage due to overlaps, it will still be simplified, but invalid topology such as crossing edges will still be invalid.

Parameters:

• tolerance (float) – A tolerance parameter in linear units.

• preserveBoundary (bool) – Set to True to preserve the outside edges of the coverage without simplification, or False to allow them to be simplified.

This method requires a QGIS build based on GEOS 3.12 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.11 or earlier.

See also

validateCoverage()

New in version 3.36.

Return type:

QgsGeometry

singleSidedBuffer(self, distance: float, segments: int, side: Qgis.BufferSide, joinStyle: Qgis.JoinStyle = Qgis.JoinStyle.Round, miterLimit: float = 2) → QgsGeometry

Returns a single sided buffer for a (multi)line geometry. The buffer is only applied to one side of the line.

Parameters:

• distance (float) – buffer distance

• segments (int) – for round joins, number of segments to approximate quarter-circle

• side (Qgis.BufferSide) – side of geometry to buffer

• joinStyle (Qgis.JoinStyle = Qgis.JoinStyle.Round) – join style for corners

• miterLimit (float = 2) – limit on the miter ratio used for very sharp corners

Return type:

QgsGeometry

Returns:

buffered geometry, or an empty geometry if buffer could not be calculated

See also

buffer()

See also

taperedBuffer()

New in version 3.0.

smooth(self, iterations: int = 1, offset: float = 0.25, minimumDistance: float = -1, maxAngle: float = 180) → QgsGeometry

Smooths a geometry by rounding off corners using the Chaikin algorithm. This operation roughly doubles the number of vertices in a geometry.

If input geometries contain Z or M values, these will also be smoothed and the output geometry will retain the same dimensionality as the input geometry.

Parameters:

• iterations (int = 1) – number of smoothing iterations to run. More iterations results in a smoother geometry

• offset (float = 0.25) – fraction of line to create new vertices along, between 0 and 1.0, e.g., the default value of 0.25 will create new vertices 25% and 75% along each line segment of the geometry for each iteration. Smaller values result in “tighter” smoothing.

• minimumDistance (float = -1) – minimum segment length to apply smoothing to

• maxAngle (float = 180) – maximum angle at node (0-180) at which smoothing will be applied

New in version 2.9.

Return type:

QgsGeometry

snappedToGrid(self, hSpacing: float, vSpacing: float, dSpacing: float = 0, mSpacing: float = 0) → QgsGeometry

Returns a new geometry with all points or vertices snapped to the closest point of the grid.

If the gridified geometry could not be calculated (or was totally collapsed) an empty geometry will be returned. Note that snapping to grid 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.

Parameters:

• hSpacing (float) – Horizontal spacing of the grid (x axis). 0 to disable.

• vSpacing (float) – Vertical spacing of the grid (y axis). 0 to disable.

• dSpacing (float = 0) – Depth spacing of the grid (z axis). 0 (default) to disable.

• mSpacing (float = 0) – Custom dimension spacing of the grid (m axis). 0 (default) to disable.

New in version 3.0.

Return type:

QgsGeometry

splitGeometry(self, splitLine: List[QgsPoint | QgsPointXY], topological: bool, splitFeature: bool = True) → Tuple[Qgis.GeometryOperationResult, List[QgsPoint] | List[QgsPointXY], List[QgsPoint] | List[QgsPointXY]]

Splits this geometry according to a given line.

Parameters:

• splitLine (List[Union[QgsPoint) – the line that splits the geometry

• topological (bool) – True if topological editing is enabled

• splitFeature (bool = True) – Set to True if you want to split a feature, otherwise set to False to split parts

Returns:

a tuple (Qgis.GeometryOperationResult, List[QgsGeometry], List[Union[QgsPoint, QgsPointXY]]) (result code, list of new geometries, list of topological points)

Example:

geometry = QgsGeometry.fromWkt('CompoundCurveZ ((2749546.2003820720128715 1262904.45356595050543547 100, 2749557.82053794478997588 1262920.05570670193992555 200))')
split_line = [QgsPoint(2749544.19, 1262914.79), QgsPoint(2749557.64, 1262897.30)]
result, new_geometries, point_xy = geometry.splitGeometry(split_line, False)
print(geometry.asWkt(2))
> LineStringZ (2749549.12 1262908.38 125.14, 2749557.82 1262920.06 200)

splitGeometry(self, curve: QgsCurve, preserveCircular: bool, topological: bool, splitFeature: bool = True) -> Tuple[Qgis.GeometryOperationResult, List[QgsGeometry], List[QgsPoint]] Splits this geometry according to a given curve.

Parameters:

curve – the curve that splits the geometry

param[out] newGeometries list of new geometries that have been created with the splitLine. If the geometry is 3D, a linear interpolation of the z value is performed on the geometry at split points, see example. :param preserveCircular: whether if circular strings are preserved after splitting :param topological: True if topological editing is enabled param[out] topologyTestPoints points that need to be tested for topological completeness in the dataset :param splitFeature: Set to True if you want to split a feature, otherwise set to False to split parts

Return type:

Tuple[Qgis.GeometryOperationResult, Union[List[QgsPoint], List[QgsPointXY]], Union[List[QgsPoint], List[QgsPointXY]]]

Returns:

OperationResult a result code: success or reason of failure

New in version 3.16.

sqrDistToVertexAt(self, point: QgsPointXY, atVertex: int) → float

Returns the squared Cartesian distance between the given point to the given vertex index (vertex at the given position number, ring and item (first number is index 0))

Parameters:

• point (QgsPointXY) –

• atVertex (int) –

Return type:

float

squareWaves(self, wavelength: float, amplitude: float, strictWavelength: bool = False) → QgsGeometry

Constructs square waves along the boundary of the geometry, with the specified wavelength and amplitude.

By default the wavelength argument is treated as a “maximum wavelength”, where the actual wavelength will be dynamically adjusted so that an exact number of square waves are created along the boundaries of the geometry. If strictWavelength is set to True then the wavelength will be used exactly and an incomplete pattern may be used for the final waveform.

See also

squareWavesRandomized()

New in version 3.24.

Parameters:

• wavelength (float) –

• amplitude (float) –

• strictWavelength (bool = False) –

Return type:

QgsGeometry

squareWavesRandomized(self, minimumWavelength: float, maximumWavelength: float, minimumAmplitude: float, maximumAmplitude: float, seed: int = 0) → QgsGeometry

Constructs randomized square waves along the boundary of the geometry, with the specified wavelength and amplitude ranges.

The minimumWavelength and maximumWavelength arguments set the range for the randomized wavelength. This is evaluated for each individual square waveform created along the geometry boundaries, so the resultant geometry will consist of many different wavelengths.

Similarly, the minimumAmplitude and maximumAmplitude arguments define the range for the randomized amplitude of the square components. Randomized amplitude values will be calculated individually for squares placed on each either side of the input geometry boundaries.

Optionally, a specific random seed can be used when generating points. If seed is 0, then a completely random sequence of points will be generated.

See also

squareWaves()

New in version 3.24.

Parameters:

• minimumWavelength (float) –

• maximumWavelength (float) –

• minimumAmplitude (float) –

• maximumAmplitude (float) –

• seed (int = 0) –

Return type:

QgsGeometry

staticMetaObject = <PyQt5.QtCore.QMetaObject object>

subdivide(self, maxNodes: int = 256, parameters: QgsGeometryParameters = QgsGeometryParameters()) → QgsGeometry

Subdivides the geometry. The returned geometry will be a collection containing subdivided parts from the original geometry, where no part has more then the specified maximum number of nodes (maxNodes).

This is useful for dividing a complex geometry into less complex parts, which are better able to be spatially indexed and faster to perform further operations such as intersects on. The returned geometry parts may not be valid and may contain self-intersections.

The minimum allowed value for maxNodes is 8.

Curved geometries will be segmentized before subdivision.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Since QGIS 3.28 the optional parameters argument can be used to specify parameters which control the subdivision results.

New in version 3.0.

Parameters:

• maxNodes (int = 256) –

• parameters (QgsGeometryParameters = QgsGeometryParameters()) –

Return type:

QgsGeometry

symDifference(self, geometry: QgsGeometry, parameters: QgsGeometryParameters = QgsGeometryParameters()) → QgsGeometry

Returns a geometry representing the points making up this geometry that do not make up other.

If the input is a NULL geometry, the output will also be a NULL geometry.

If an error was encountered while creating the result, more information can be retrieved by calling lastError() on the returned geometry.

Since QGIS 3.28 the optional parameters argument can be used to specify parameters which control the difference results.

Parameters:

• geometry (QgsGeometry) –

• parameters (QgsGeometryParameters = QgsGeometryParameters()) –

Return type:

QgsGeometry

taperedBuffer(self, startWidth: float, endWidth: float, segments: int) → QgsGeometry

Calculates a variable width buffer (“tapered buffer”) for a (multi)curve geometry.

The buffer begins at a width of startWidth at the start of each curve, and ends at a width of endWidth. Note that unlike buffer() methods, startWidth and endWidth are the diameter of the buffer at these points, not the radius.

The segments argument specifies the number of segments to approximate quarter-circle curves in the buffer.

Non (multi)curve input geometries will return a null output geometry.

See also

buffer()

See also

singleSidedBuffer()

See also

variableWidthBufferByM()

New in version 3.2.

Parameters:

• startWidth (float) –

• endWidth (float) –

• segments (int) –

Return type:

QgsGeometry

toggleCircularAtVertex(self, atVertex: int) → bool

Converts the vertex at the given position from/to circular

Return type:

bool

Returns:

False if atVertex does not correspond to a valid vertex on this geometry (including if this geometry is a Point), or if the specified vertex can’t be converted (e.g. start/end points).

New in version 3.20.

Parameters:

atVertex (int) –

touches(self, geometry: QgsGeometry) → bool

Returns True if the geometry touches another geometry.

Note

For performance critical code, or when testing for touches against many different geometries, consider using QgsGeometryEngine instead. This approach can be many orders of magnitude faster than calling touches() directly. See createGeometryEngine() for details on how to use the QgsGeometryEngine class.

New in version 1.5.

Parameters:

geometry (QgsGeometry) –

Return type:

bool

transform(self, ct: QgsCoordinateTransform, direction: Qgis.TransformDirection = Qgis.TransformDirection.Forward, transformZ: bool = False) → Qgis.GeometryOperationResult

Transforms this geometry as described by the coordinate transform ct.

The transformation defaults to a forward transform, but the direction can be swapped by setting the direction argument.

By default, z-coordinates are not transformed, even if the coordinate transform includes a vertical datum transformation. To transform z-coordinates, set transformZ to True. 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).

Returns:

OperationResult a result code: success or reason of failure

transform(self, t: QTransform, zTranslate: float = 0, zScale: float = 1, mTranslate: float = 0, mScale: float = 1) -> Qgis.GeometryOperationResult 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.

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

Parameters:

• ct (QgsCoordinateTransform) –

• direction (Qgis.TransformDirection = Qgis.TransformDirection.Forward) –

• transformZ (bool = False) –

translate(self, dx: float, dy: float, dz: float = 0, dm: float = 0) → Qgis.GeometryOperationResult

Translates this geometry by dx, dy, dz and dm.

Return type:

Qgis.GeometryOperationResult

Returns:

OperationResult a result code: success or reason of failure

Parameters:

• dx (float) –

• dy (float) –

• dz (float = 0) –

• dm (float = 0) –

triangularWaves(self, wavelength: float, amplitude: float, strictWavelength: bool = False) → QgsGeometry

Constructs triangular waves along the boundary of the geometry, with the specified wavelength and amplitude.

By default the wavelength argument is treated as a “maximum wavelength”, where the actual wavelength will be dynamically adjusted so that an exact number of triangular waves are created along the boundaries of the geometry. If strictWavelength is set to True then the wavelength will be used exactly and an incomplete pattern may be used for the final waveform.

See also

triangularWavesRandomized()

New in version 3.24.

Parameters:

• wavelength (float) –

• amplitude (float) –

• strictWavelength (bool = False) –

Return type:

QgsGeometry

triangularWavesRandomized(self, minimumWavelength: float, maximumWavelength: float, minimumAmplitude: float, maximumAmplitude: float, seed: int = 0) → QgsGeometry

Constructs randomized triangular waves along the boundary of the geometry, with the specified wavelength and amplitude ranges.

The minimumWavelength and maximumWavelength arguments set the range for the randomized wavelength. This is evaluated for each individual triangular waveform created along the geometry boundaries, so the resultant geometry will consist of many different wavelengths.

Similarly, the minimumAmplitude and maximumAmplitude arguments define the range for the randomized amplitude of the triangular components. Randomized amplitude values will be calculated individually for triangles placed on each either side of the input geometry boundaries.

Optionally, a specific random seed can be used when generating points. If seed is 0, then a completely random sequence of points will be generated.

See also

triangularWaves()

New in version 3.24.

Parameters:

• minimumWavelength (float) –

• maximumWavelength (float) –

• minimumAmplitude (float) –

• maximumAmplitude (float) –

• seed (int = 0) –

Return type:

QgsGeometry

type(self) → Qgis.GeometryType

Returns type of the geometry as a Qgis.GeometryType

See also

wkbType()

Return type:

Qgis.GeometryType

unaryUnion(geometries: Iterable[QgsGeometry], parameters: QgsGeometryParameters = QgsGeometryParameters()) → QgsGeometry

Compute the unary union on a list of geometries. May be faster than an iterative union on a set of geometries. The returned geometry will be fully noded, i.e. a node will be created at every common intersection of the input geometries. An empty geometry will be returned in the case of errors.

Since QGIS 3.28 the optional parameters argument can be used to specify parameters which control the union results.

Parameters:

• geometries (Iterable[QgsGeometry]) –

• parameters (QgsGeometryParameters = QgsGeometryParameters()) –

Return type:

QgsGeometry

unionCoverage(self) → QgsGeometry

Optimized union algorithm for polygonal inputs that are correctly noded and do not overlap. It may generate an error (returning a null geometry) for inputs that do not satisfy this constraint, however this is not guaranteed.

The input geometry is the polygonal coverage to union, stored in a geometry collection. All members must be POLYGON or MULTIPOLYGON.

See also

validateCoverage()

New in version 3.36.

Return type:

QgsGeometry

validateCoverage(self, gapWidth: float) → Tuple[Qgis.CoverageValidityResult, QgsGeometry]

Analyze a coverage (represented as a collection of polygonal geometry with exactly matching edge geometry) to find places where the assumption of exactly matching edges is not met.

The input geometry is the polygonal coverage to access, stored in a geometry collection. All members must be POLYGON or MULTIPOLYGON.

Parameters:

gapWidth (float) – The maximum width of gaps to detect.

Return type:

Tuple[Qgis.CoverageValidityResult, QgsGeometry]

Returns:

• validity check result

• invalidEdges: When there are invalidities in the coverage, will be set with a geometry collection of the same length as the input, with a MULTILINESTRING of the error edges for each invalid polygon, or an EMPTY where the polygon is a valid participant in the coverage.

This method requires a QGIS build based on GEOS 3.12 or later.

Raises:

QgsNotSupportedException – on QGIS builds based on GEOS 3.11 or earlier.

See also

simplifyCoverageVW()

New in version 3.36.

validateGeometry(self, method: Qgis.GeometryValidationEngine = Qgis.GeometryValidationEngine.QgisInternal, flags: Qgis.GeometryValidityFlags | Qgis.GeometryValidityFlag = Qgis.GeometryValidityFlags()) → List[QgsGeometry.Error]

Validates geometry and produces a list of geometry errors. The method argument dictates which validator to utilize.

The flags parameter indicates optional flags which control the type of validity checking performed.

New in version 1.5.

Parameters:

• method (Qgis.GeometryValidationEngine = Qgis.GeometryValidationEngine.QgisInternal) –

• flags (Union[Qgis.GeometryValidityFlags) –

Return type:

List[QgsGeometry.Error]

variableWidthBufferByM(self, segments: int) → QgsGeometry

Calculates a variable width buffer for a (multi)linestring geometry, where the width at each node is taken from the linestring m values.

The segments argument specifies the number of segments to approximate quarter-circle curves in the buffer.

Non (multi)linestring input geometries will return a null output geometry.

See also

buffer()

See also

singleSidedBuffer()

See also

taperedBuffer()

New in version 3.2.

Parameters:

segments (int) –

Return type:

QgsGeometry

vertexAt(self, atVertex: int) → QgsPoint

Returns coordinates of a vertex.

Parameters:

atVertex (int) – index of the vertex

Return type:

QgsPoint

Returns:

Coordinates of the vertex or empty QgsPoint on error

vertexIdFromVertexNr(self, number: int) → Tuple[bool, QgsVertexId]

Calculates the vertex ID from a vertex number.

If a matching vertex was found, it will be stored in id.

Returns True if vertex was found.

See also

vertexNrFromVertexId()

New in version 2.10.

Parameters:

number (int) –

Return type:

Tuple[bool, QgsVertexId]

vertexNrFromVertexId(self, id: QgsVertexId) → int

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.

See also

vertexIdFromVertexNr()

New in version 2.10.

Parameters:

id (QgsVertexId) –

Return type:

int

vertices(self) → QgsVertexIterator

Returns a read-only, Java-style iterator for traversal of vertices of all the geometry, including all geometry parts and rings.

Warning

The iterator returns a copy of individual vertices, and accordingly geometries cannot be modified using the iterator. See transformVertices() for a safe method to modify vertices “in-place”.

Example

# print the x and y coordinate for each vertex in a LineString
geometry = QgsGeometry.fromWkt( 'LineString( 0 0, 1 1, 2 2)' )
for v in geometry.vertices():
    print(v.x(), v.y())

# vertex iteration includes all parts and rings
geometry = QgsGeometry.fromWkt( 'MultiPolygon((( 0 0, 0 10, 10 10, 10 0, 0 0 ),( 5 5, 5 6, 6 6, 6 5, 5 5)),((20 2, 22 2, 22 4, 20 4, 20 2)))' )
for v in geometry.vertices():
    print(v.x(), v.y())

See also

parts()

New in version 3.0.

rtype:

QgsVertexIterator

voronoiDiagram(self, extent: QgsGeometry = QgsGeometry(), tolerance: float = 0, edgesOnly: bool = False) → QgsGeometry

Creates a Voronoi diagram for the nodes contained within the geometry.

Returns the Voronoi polygons for the nodes contained within the geometry. If extent is specified then it will be used as a clipping envelope for the diagram. If no extent is set then the clipping envelope will be automatically calculated. In either case the diagram will be clipped to the larger of the provided envelope OR the envelope surrounding all input nodes. The tolerance parameter specifies an optional snapping tolerance which can be used to improve the robustness of the diagram calculation. If edgesOnly is True than line string boundary geometries will be returned instead of polygons. An empty geometry will be returned if the diagram could not be calculated.

New in version 3.0.

Parameters:

• extent (QgsGeometry = QgsGeometry()) –

• tolerance (float = 0) –

• edgesOnly (bool = False) –

Return type:

QgsGeometry

within(self, geometry: QgsGeometry) → bool

Returns True if the geometry is completely within another geometry.

Note

For performance critical code, or when testing for within against many different geometries, consider using QgsGeometryEngine instead. This approach can be many orders of magnitude faster than calling within() directly. See createGeometryEngine() for details on how to use the QgsGeometryEngine class.

New in version 1.5.

Parameters:

geometry (QgsGeometry) –

Return type:

bool

wkbSize(self, flags: QgsAbstractGeometry.WkbFlags | QgsAbstractGeometry.WkbFlag = QgsAbstractGeometry.WkbFlags()) → int

Returns the length of the QByteArray returned by asWkb()

The optional flags argument specifies flags controlling WKB export behavior

New in version 3.16.

Parameters:

flags (Union[QgsAbstractGeometry.WkbFlags) –

Return type:

int

wkbType(self) → Qgis.WkbType

Returns type of the geometry as a WKB type (point / linestring / polygon etc.)

See also

type()

Return type:

Qgis.WkbType