Class: QgsGeometry

class qgis.core.QgsGeometry

Bases: sip.wrapper

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.

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.

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.

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

boundingBox

Returns the 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.

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.

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

convertToMultiType

Converts single type geometry into multitype geometry e.g.

convertToSingleType

Converts multi type geometry into single type geometry e.g.

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

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.

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.

fromMultiPointXY

Creates a new geometry from a QgsMultiPointXY object

fromMultiPolygonXY

Creates a new geometry from a QgsMultiPolygon

fromMultiPolylineXY

Creates a new geometry from a QgsMultiPolylineXY object

fromPointXY

Creates a new geometry from a QgsPointXY object

fromPolygonXY

Creates a new geometry from a QgsPolygon

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.

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 geometry() ).

isSimple

Determines whether the geometry is simple (according to OGC definition), i.e.

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.

moveVertex

Moves the vertex at the given position number and item (first number is index 0) to the given coordinates.

nearestPoint

Returns the nearest point on this geometry to another geometry.

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.

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

set

Sets the underlying geometry store.

shortestLine

Returns the shortest line joining this geometry to another geometry.

simplify

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

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))

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.

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.

type

Returns type of the geometry as a QgsWkbTypes.GeometryType

unaryUnion

Compute the unary union on a list of geometries.

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.

wkbType

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

Attributes

AddPartNotMultiGeometry

AddPartSelectedGeometryNotFound

AddRingCrossesExistingRings

AddRingNotClosed

AddRingNotInExistingFeature

AddRingNotValid

CapFlat

CapRound

CapSquare

FlagAllowSelfTouchingHoles

GeometryEngineError

InvalidBaseGeometry

InvalidInputGeometryType

JoinStyleBevel

JoinStyleMiter

JoinStyleRound

LayerNotEditable

NothingHappened

SelectionIsEmpty

SelectionIsGreaterThanOne

SideLeft

SideRight

SplitCannotSplitPoint

Success

ValidatorGeos

ValidatorQgisInternal

staticMetaObject

AddPartNotMultiGeometry = 1008
AddPartSelectedGeometryNotFound = 1007
AddRingCrossesExistingRings = 1011
AddRingNotClosed = 1009
AddRingNotInExistingFeature = 1012
AddRingNotValid = 1010
class BufferSide

Bases: int

baseClass

alias of QgsGeometry

CapFlat = 2
CapRound = 1
CapSquare = 3
class EndCapStyle

Bases: int

baseClass

alias of QgsGeometry

class Error

Bases: sip.wrapper

QgsGeometry.Error(m: str) QgsGeometry.Error(m: str, p: QgsPointXY) QgsGeometry.Error(QgsGeometry.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

FlagAllowSelfTouchingHoles = 1
GeometryEngineError = 1005
InvalidBaseGeometry = 1001
InvalidInputGeometryType = 1002
class JoinStyle

Bases: int

baseClass

alias of QgsGeometry

JoinStyleBevel = 3
JoinStyleMiter = 2
JoinStyleRound = 1
LayerNotEditable = 1006
NothingHappened = 1000
class OperationResult

Bases: int

SelectionIsEmpty = 1003
SelectionIsGreaterThanOne = 1004
SideLeft = 0
SideRight = 1
SplitCannotSplitPoint = 1013
Success = 0
class ValidationMethod

Bases: int

ValidatorGeos = 1
ValidatorQgisInternal = 0
class ValidityFlag

Bases: int

class ValidityFlags

Bases: sip.wrapper

QgsGeometry.ValidityFlags(Union[QgsGeometry.ValidityFlags, QgsGeometry.ValidityFlag]) QgsGeometry.ValidityFlags(QgsGeometry.ValidityFlags)

addPart(self, part: QgsAbstractGeometry, geomType: QgsWkbTypes.GeometryType = QgsWkbTypes.UnknownGeometry) → QgsGeometry.OperationResult

Adds a new part to this geometry.

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

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

Return type

QgsGeometry.OperationResult

Returns

OperationResult a result code: success or reason of failure

addPartGeometry(self, newPart: QgsGeometry) → QgsGeometry.OperationResult

Adds a new island polygon to a multipolygon feature

Return type

QgsGeometry.OperationResult

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: QgsWkbTypes.GeometryType = QgsWkbTypes.UnknownGeometry) → QgsGeometry.OperationResult

Adds a new part to a the geometry.

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

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

Return type

QgsGeometry.OperationResult

Returns

OperationResult a result code: success or reason of failure

addPointsXY(self, points: Iterable[QgsPointXY], geomType: QgsWkbTypes.GeometryType = QgsWkbTypes.UnknownGeometry) → QgsGeometry.OperationResult

Adds a new part to a the geometry.

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

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

Return type

QgsGeometry.OperationResult

Returns

OperationResult a result code: success or reason of failure

addRing(self, ring: Iterable[QgsPointXY]) → QgsGeometry.OperationResult

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) -> QgsGeometry.OperationResult Adds a new ring to this geometry. This makes only sense for polygon and multipolygons.

Parameters

ring – The ring to be added

Return type

QgsGeometry.OperationResult

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:

1. If the given vertex index is at the end of a linestring, the adjacent index will be -1 (for “no adjacent vertex”) 2. 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

New in version 3.0.

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. If the geometry is not a multi-point type, a TypeError will be raised. If the geometry is null, a ValueError will be raised.

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. If the geometry is not a multi-polygon type, a TypeError will be raised. If the geometry is null, a ValueError will be raised.

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. If the geometry is not a multi-linestring type, a TypeError will be raised. If the geometry is null, a ValueError will be raised.

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. If the geometry is not a single-point type, a TypeError will be raised. If the geometry is null, a ValueError will be raised.

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. If the geometry is not a single-polygon type, a TypeError will be raised. If the geometry is null, a ValueError will be raised.

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) geometry types. If the geometry is not a single-line type, a TypeError will be raised. If the geometry is null, a ValueError will be raised.

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.

New in version 2.7.

Return type

QPolygonF

asWkb(self) → QByteArray

Export the geometry to WKB

New in version 3.0.

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 other error during intersection removal

New in version 1.5.

boundingBox(self) → QgsRectangle

Returns the bounding box of the geometry.

Return type

QgsRectangle

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

taperedBuffer()

buffer(self, distance: float, segments: int, endCapStyle: QgsGeometry.EndCapStyle, joinStyle: QgsGeometry.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

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 error() 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()

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

  • afterVertex – Receives index of the vertex after the closest segment. The vertex before the closest segment is always afterVertex - 1

  • leftOf – Out: Returns if the point lies on the left of left 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)

  • 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

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

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

  • afterVertex – 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

Return type

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

Returns

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

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

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

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) → 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 error() on the returned geometry.

Note

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

Parameters

geometry (QgsGeometry) –

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) –

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.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())

# 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

parts()

See also

vertices()

New in version 3.6.

Return type

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.

New in version 1.5.

Parameters

p (QgsPointXY) –

Return type

bool

convertGeometryCollectionToSubclass(self, geomType: QgsWkbTypes.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 (QgsWkbTypes.GeometryType) –

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

Upgrades a point list from QgsPointXY to QgsPoint

Parameters

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

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

New in version 2.10.

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

Try to convert the geometry to the requested type

Parameters
  • destType (QgsWkbTypes.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.

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 error() on the returned geometry.

Return type

QgsGeometry

createGeometryEngine(geometry: QgsAbstractGeometry) → QgsGeometryEngine

Creates and returns a new geometry engine

Parameters

geometry (QgsAbstractGeometry) –

Return type

QgsGeometryEngine

createPolygonFromQPolygonF(polygon: QPolygonF) → object

Creates a QgsPolygonXYfrom a QPolygonF.

Parameters

polygon (QPolygonF) – source polygon

Return type

object

Returns

QgsPolygon

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

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.

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.

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) → 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 error() on the returned geometry.

Parameters

geometry (QgsGeometry) –

Return type

QgsGeometry

disjoint(self, geometry: QgsGeometry) → bool

Returns True if the geometry is disjoint of another geometry.

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

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.

New in version 3.6.

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 QgsMultiPolygon

Parameters

multipoly (object) –

Return type

QgsGeometry

fromMultiPolylineXY(multiline: object) → QgsGeometry

Creates a new geometry from a QgsMultiPolylineXY object

Parameters

multiline (object) –

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 geometry from a QgsPolygon

Parameters

polygon (object) –

Return type

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: Union[QPointF, QPoint]) → 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: Union[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.

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.

New in version 3.0.

Parameters
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.

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) → 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 error() on the returned geometry.

Parameters

geometry (QgsGeometry) –

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.

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.

Parameters

rectangle (QgsRectangle) –

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: Union[QgsGeometry.ValidityFlags, QgsGeometry.ValidityFlag] = 0) → 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[QgsGeometry.ValidityFlags) –

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 geometry() ).

See also

get()

See also

isEmpty()

New in version 2.10.

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

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.

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) → 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 error() on the returned geometry.

Return type

QgsGeometry

Returns

new valid QgsGeometry or null geometry on error

Note

Ported from PostGIS ST_MakeValid() and it should return equivalent results.

New in version 3.0.

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
  • radius – Radius of the minimal enclosing circle returned

  • 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

New in version 3.0.

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 point on this geometry to another geometry.

See also

shortestLine()

New in version 2.14.

Parameters

other (QgsGeometry) –

Return type

QgsGeometry

offsetCurve(self, distance: float, segments: int, joinStyle: QgsGeometry.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 (QgsGeometry.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.

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.

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.

Return type

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 error() on the returned geometry.

See also

centroid()

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]

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. If the geometry is not a polygon type, a TypeError will be raised. If the geometry is null, a ValueError will be raised.

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.

New in version 2.10.

Return type

bool

reshapeGeometry(self, reshapeLineString: QgsLineString) → QgsGeometry.OperationResult

Replaces a part of this geometry with another line

Return type

QgsGeometry.OperationResult

Returns

OperationResult a result code: success or reason of failure

Parameters

reshapeLineString (QgsLineString) –

rotate(self, rotation: float, center: QgsPointXY) → QgsGeometry.OperationResult

Rotate this geometry around the Z axis

Parameters
  • rotation (float) – clockwise rotation in degrees

  • center (QgsPointXY) – rotation center

Return type

QgsGeometry.OperationResult

Returns

OperationResult a result code: success or reason of failure

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) –

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

singleSidedBuffer(self, distance: float, segments: int, side: QgsGeometry.BufferSide, joinStyle: QgsGeometry.JoinStyle = QgsGeometry.JoinStyleRound, 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 (QgsGeometry.BufferSide) – side of geometry to buffer

  • joinStyle (QgsGeometry.JoinStyle = QgsGeometry.JoinStyleRound) – 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: Iterable[QgsPointXY], topological: bool) → Tuple[QgsGeometry.OperationResult, List[QgsGeometry], List[QgsPointXY]]

Splits this geometry according to a given line.

Parameters

splitLine (Iterable[QgsPointXY]) – the line that splits the geometry

param[out] newGeometries list of new geometries that have been created with the split :type topological: bool :param topological: True if topological editing is enabled param[out] topologyTestPoints points that need to be tested for topological completeness in the dataset

Returns

OperationResult a result code: success or reason of failure

Deprecated since version QGIS: 3.12 - will be removed in QGIS 4.0. Use the variant which accepts QgsPoint objects instead of QgsPointXY.

splitGeometry(self, splitLine: Iterable[QgsPoint], topological: bool) -> Tuple[QgsGeometry.OperationResult, List[QgsGeometry], List[QgsPoint]] Splits this geometry according to a given line.

Parameters

splitLine – the line that splits the geometry

param[out] newGeometries list of new geometries that have been created with the split :param topological: True if topological editing is enabled param[out] topologyTestPoints points that need to be tested for topological completeness in the dataset

Return type

Tuple[QgsGeometry.OperationResult, List[QgsGeometry], List[QgsPointXY]]

Returns

OperationResult a result code: success or reason of failure

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
Return type

float

staticMetaObject = <PyQt5.QtCore.QMetaObject object>
subdivide(self, maxNodes: int = 256) → 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 error() on the returned geometry.

New in version 3.0.

Parameters

maxNodes (int = 256) –

Return type

QgsGeometry

symDifference(self, geometry: QgsGeometry) → 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 error() on the returned geometry.

Parameters

geometry (QgsGeometry) –

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()

New in version 3.2.

Parameters
  • startWidth (float) –

  • endWidth (float) –

  • segments (int) –

Return type

QgsGeometry

touches(self, geometry: QgsGeometry) → bool

Returns True if the geometry touches another geometry.

New in version 1.5.

Parameters

geometry (QgsGeometry) –

Return type

bool

transform(self, ct: QgsCoordinateTransform, direction: QgsCoordinateTransform.TransformDirection = QgsCoordinateTransform.ForwardTransform, transformZ: bool = False) → QgsGeometry.OperationResult

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) -> QgsGeometry.OperationResult 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

QgsGeometry.OperationResult

Returns

OperationResult a result code: success or reason of failure

Parameters
  • ct (QgsCoordinateTransform) –

  • direction (QgsCoordinateTransform.TransformDirection = QgsCoordinateTransform.ForwardTransform) –

  • transformZ (bool = False) –

translate(self, dx: float, dy: float, dz: float = 0, dm: float = 0) → QgsGeometry.OperationResult

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

Return type

QgsGeometry.OperationResult

Returns

OperationResult a result code: success or reason of failure

Parameters
  • dx (float) –

  • dy (float) –

  • dz (float = 0) –

  • dm (float = 0) –

type(self) → QgsWkbTypes.GeometryType

Returns type of the geometry as a QgsWkbTypes.GeometryType

See also

wkbType()

Return type

QgsWkbTypes.GeometryType

unaryUnion(geometries: Iterable[QgsGeometry]) → 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.

Parameters

geometries (Iterable[QgsGeometry]) –

Return type

QgsGeometry

validateGeometry(self, method: QgsGeometry.ValidationMethod = QgsGeometry.ValidatorQgisInternal, flags: Union[QgsGeometry.ValidityFlags, QgsGeometry.ValidityFlag] = 0) → 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
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

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 QgsPoint(0,0) 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.

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.

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.

Return type

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.

New in version 1.5.

Parameters

geometry (QgsGeometry) –

Return type

bool

wkbType(self) → QgsWkbTypes.Type

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

See also

type()

Return type

QgsWkbTypes.Type