Class: QgsGraphBuilderInterface

Interface for creating a graph.

Contains the settings of the graph.

QgsGraphBuilder and QgsGraphDirector both use a “builder” design pattern

Class Hierarchy

Subclasses

QgsGraphBuilder

Used for making the QgsGraph object.

Methods

coordinateTransformationEnabled	Returns coordinate transformation enabled
destinationCrs	Returns destinaltion CRS
distanceArea	Returns measurement tool
topologyTolerance	Returns topology tolerance

Virtual Methods

In PyQGIS, only methods marked as virtual can be safely overridden in a Python subclass of QgsGraphBuilderInterface. See the FAQ for more details.

addEdge	Add edge to the graph
addVertex	Add vertex to the graph

class qgis.analysis.QgsGraphBuilderInterface

Bases: object

__init__(crs: QgsCoordinateReferenceSystem, ctfEnabled: bool = True, topologyTolerance: float = 0, ellipsoidID: str | None = '')

Default constructor

Parameters:

• crs (QgsCoordinateReferenceSystem) – Coordinate reference system for new graph vertex

• ctfEnabled (bool = True) – enable coordinate transform from source graph CRS to CRS graph

• topologyTolerance (float = 0) – sqrt distance between source point as one graph vertex

• ellipsoidID (Optional[str] = '') – ellipsoid for edge measurement

__init__(a0: QgsGraphBuilderInterface)

Parameters:

a0 (QgsGraphBuilderInterface)

virtual addEdge(self, pt1id: int, pt1: QgsPointXY, pt2id: int, pt2: QgsPointXY, strategies: Iterable[Any])

Add edge to the graph

Parameters:

• pt1id (int) – first vertex identificator

• pt1 (QgsPointXY) – first vertex coordinates

• pt2id (int) – second vertex identificator

• pt2 (QgsPointXY) – second vertex coordinates

• strategies (Iterable[Any]) – optimization strategies

Note

pt1id, pt1 and pt2id, pt2 is a redundant interface. You can use vertex coordinates or their identificators.

virtual addVertex(self, id: int, pt: QgsPointXY)

Add vertex to the graph

Parameters:

• id (int) – vertex identifier

• pt (QgsPointXY) – vertex coordinates

Note

id and pt are redundant. You can use pt or id to identify the vertex

coordinateTransformationEnabled(self) → bool

Returns coordinate transformation enabled

Return type:

bool

destinationCrs(self) → QgsCoordinateReferenceSystem

Returns destinaltion CRS

Return type:

QgsCoordinateReferenceSystem

distanceArea(self) → QgsDistanceArea | None

Returns measurement tool

Return type:

Optional[QgsDistanceArea]

topologyTolerance(self) → float

Returns topology tolerance

Return type:

float