Subgroup: Line

Class: QgsLineString¶

class qgis.core.QgsLineString¶

Bases: qgis._core.QgsCurve

Line string geometry type, with support for z-dimension and m-values.

New in version 2.10: Methods

`addMValue`
`addToPainterPath`
`addVertex`	Adds a new vertex to the end of the line string.
`addZValue`
`adjacentVertices`
`append`	Appends the contents of another line string to the end of this line string.
`area`	Returns the area of the geometry.
`asGml2`
`asGml3`
`asJson`
`asQPolygonF`	Returns a QPolygonF representing the points.
`asWkb`
`asWkt`
`boundary`
`boundingBox`
`calculateBoundingBox`
`centroid`
`childCount`
`childGeometry`
`childPoint`
`clear`
`clearCache`
`clone`
`close`	Closes the line string by appending the first point to the end of the line, if it is not already closed.
`closestSegment`
`convertTo`
`coordinateSequence`
`createEmptyWithSameType`
`curveToLine`	Returns a new line string geometry corresponding to a segmentized approximation of the curve.
`deleteVertex`
`dimension`
`draw`
`drawAsPolygon`
`dropMValue`
`dropZValue`
`endPoint`
`equals`
`extend`	Extends the line geometry by extrapolating out the start or end of the line by a specified distance.
`fromWkb`
`fromWkt`
`geometryType`
`hasChildGeometries`
`hasCurvedSegments`	Returns true if the geometry contains curved segments
`insertVertex`
`is3D`	Returns true if the geometry is 3D and contains a z-value.
`isClosed`	Returns true if the curve is closed.
`isEmpty`
`isMeasure`	Returns true if the geometry contains m values.
`isRing`	Returns true if the curve is a ring.
`length`
`mAt`	Returns the m value of the specified node in the line string.
`moveVertex`
`nCoordinates`
`nextVertex`
`numPoints`
`partCount`
`perimeter`	Returns the perimeter of the geometry.
`pointAt`
`pointN`	Returns the specified point from inside the line string.
`points`
`removeDuplicateNodes`
`reversed`
`ringCount`
`segmentLength`
`segmentize`	Returns a geometry without curves.
`setMAt`	Sets the m value of the specified node in the line string.
`setPoints`	Resets the line string to match the specified list of points.
`setXAt`	Sets the x-coordinate of the specified node in the line string.
`setYAt`	Sets the y-coordinate of the specified node in the line string.
`setZAt`	Sets the z-coordinate of the specified node in the line string.
`setZMTypeFromSubGeometry`
`snappedToGrid`
`startPoint`
`sumUpArea`
`toCurveType`	Returns the geometry converted to the more generic curve type `QgsCompoundCurve`
`transform`	transform(self, t: QTransform, zTranslate: float = 0, zScale: float = 1, mTranslate: float = 0, mScale: float = 1)
`vertexAngle`
`vertexAt`
`vertexCount`
`vertexNumberFromVertexId`
`vertices`	Returns Java-style iterator for traversal of vertices of the geometry
`wkbType`	Returns the WKB type of the geometry.
`wktTypeStr`	Returns the WKT type string of the geometry.
`xAt`
`yAt`
`zAt`	Returns the z-coordinate of the specified node in the line string.

Attributes

`MaximumAngle`
`MaximumDifference`

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

addToPainterPath(self, path: QPainterPath)¶

addVertex(self, pt: QgsPoint)¶

Adds a new vertex to the end of the line string.

Parameters:	pt – vertex to add

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

append(self, line: QgsLineString)¶

Appends the contents of another line string to the end of this line string.

Parameters:	line – line to append. Ownership is not transferred.

asGml2(self, doc: QDomDocument, precision: int = 17, ns: str = '') → QDomElement¶

asGml3(self, doc: QDomDocument, precision: int = 17, ns: str = '') → QDomElement¶

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

asWkb(self) → QByteArray¶

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

calculateBoundingBox(self) → QgsRectangle¶

centroid(self) → QgsPoint¶

childCount()¶

childGeometry()¶

childPoint()¶

clear(self)¶

clearCache()¶

clone(self) → QgsLineString¶

close(self)¶: Closes the line string by appending the first point to the end of the line, if it is not already closed.

closestSegment(self, pt: QgsPoint, epsilon: float = 4*DBL_EPSILON) → Tuple[float, QgsPoint, QgsVertexId, int]¶

convertTo(self, type: QgsWkbTypes.Type) → bool¶

createEmptyWithSameType(self) → QgsLineString¶

curveToLine(self, tolerance: float = M_PI_2/90, toleranceType: QgsAbstractGeometry.SegmentationToleranceType = QgsAbstractGeometry.MaximumAngle) → QgsLineString¶

Returns a new line string geometry corresponding to a segmentized approximation of the curve.

Parameters:	tolerance – segmentation tolerance toleranceType – maximum segmentation angle or maximum difference between approximation and curve*

deleteVertex(self, position: QgsVertexId) → bool¶

dimension(self) → int¶

draw(self, p: QPainter)¶

drawAsPolygon(self, p: QPainter)¶

dropMValue(self) → bool¶

dropZValue(self) → bool¶

endPoint(self) → QgsPoint¶

equals(self, other: QgsCurve) → bool¶

extend(self, startDistance: float, endDistance: float)¶: Extends the line geometry by extrapolating out the start or end of the line by a specified distance. Lines are extended using the bearing of the first or last segment in the line.

New in version 3.0.

fromWkb(self, wkb: QgsConstWkbPtr) → bool¶

fromWkt(self, wkt: str) → bool¶

geometryType(self) → str¶

hasChildGeometries()¶

insertVertex(self, position: QgsVertexId, vertex: QgsPoint) → bool¶

isEmpty(self) → bool¶

length(self) → float¶

mAt(self, index: int) → float¶

Returns the m value of the specified node in the line string.

Parameters:	index – index of node, where the first node in the line is 0
Returns:	m value of node, or `nan` if index is out of bounds or the line

does not have m values

See also

setMAt()

moveVertex(self, position: QgsVertexId, newPos: QgsPoint) → bool¶

nCoordinates(self) → int¶

numPoints(self) → int¶

pointAt(self, node: int, point: QgsPoint) → Tuple[bool, QgsVertexId.VertexType]¶

pointN(self, i: int) → QgsPoint¶

Returns the specified point from inside the line string.

Parameters:	i – index of point, starting at 0 for the first point

points(self) → object¶

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

reversed(self) → QgsLineString¶

segmentLength(self, startVertex: QgsVertexId) → float¶

setMAt(self, index: int, m: float)¶

Sets the m value of the specified node in the line string.

Parameters:	index – index of node, where the first node in the line is 0. Corresponding

node must already exist in line string, and the line string must have m values. :param m: m value of node

See also

mAt()

setPoints(self, points: object)¶

Resets the line string to match the specified list of points. The line string will inherit the dimensionality of the first point in the list.

Parameters:	points – new points for line string. If empty, line string will be cleared.

setXAt(self, index: int, x: float)¶

Sets the x-coordinate of the specified node in the line string.

Parameters:	index – index of node, where the first node in the line is 0. Corresponding

node must already exist in line string. :param x: x-coordinate of node

See also

xAt()

setYAt(self, index: int, y: float)¶

Sets the y-coordinate of the specified node in the line string.

Parameters:	index – index of node, where the first node in the line is 0. Corresponding

node must already exist in line string. :param y: y-coordinate of node

See also

yAt()

setZAt(self, index: int, z: float)¶

Sets the z-coordinate of the specified node in the line string.

Parameters:	index – index of node, where the first node in the line is 0. Corresponding

node must already exist in line string, and the line string must have z-dimension. :param z: z-coordinate of node

See also

zAt()

setZMTypeFromSubGeometry()¶

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

startPoint(self) → QgsPoint¶

sumUpArea(self) → float¶

toCurveType(self) → QgsCompoundCurve¶

Returns the geometry converted to the more generic curve type QgsCompoundCurve

Returns:	the converted geometry. Caller takes ownership*

transform(self, ct: QgsCoordinateTransform, d: QgsCoordinateTransform.TransformDirection = QgsCoordinateTransform.ForwardTransform, transformZ: bool = False)¶: transform(self, t: QTransform, zTranslate: float = 0, zScale: float = 1, mTranslate: float = 0, mScale: float = 1)

vertexAngle(self, vertex: QgsVertexId) → float¶

xAt(self, index: int) → float¶

yAt(self, index: int) → float¶

zAt(self, index: int) → float¶

Returns the z-coordinate of the specified node in the line string.

Parameters:	index – index of node, where the first node in the line is 0
Returns:	z-coordinate of node, or `nan` if index is out of bounds or the line

does not have a z dimension

See also

setZAt()