RelateNodeGraph class

Implements the simple graph of Nodes and EdgeEnd which is all that is required to determine topological relationships between Geometries. Also supports building a topological graph of a single Geometry, to allow verification of valid topology.

It is not necessary to create a fully linked PlanarGraph to determine relationships, since it is sufficient to know how the Geometries interact locally around the nodes. In fact, this is not even feasible, since it is not possible to compute exact intersection points, and hence the topology around those nodes cannot be computed robustly. The only Nodes that are created are for improper intersections; that is, nodes which occur at existing vertices of the Geometries. Proper intersections (e.g. ones which occur between the interior of line segments) have their topology determined implicitly, without creating a Node object to represent them.

@version 1.7

Constructors

RelateNodeGraph()

Properties

hashCode → int

The hash code for this object.

no setter, inherited

nodes ↔ NodeMap

getter/setter pair

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

build(GeometryGraph geomGraph) → void

computeIntersectionNodes(GeometryGraph geomGraph, int argIndex) → void

Insert nodes for all intersections on the edges of a Geometry. Label the created nodes the same as the edge label if they do not already have a label. This allows nodes created by either self-intersections or mutual intersections to be labelled. Endpoint nodes will already be labelled from when they were inserted.

copyNodesAndLabels(GeometryGraph geomGraph, int argIndex) → void

Copy all nodes from an arg geometry into this graph. The node label in the arg geometry overrides any previously computed label for that argIndex. (E.g. a node may be an intersection node with a computed label of BOUNDARY, but in the original arg Geometry it is actually in the interior due to the Boundary Determination Rule)

getNodeIterator() → Iterator

insertEdgeEnds(List ee) → void

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited