Namespace NetTopologySuite.Planargraph

Contains classes to implement a planar graph data structure.

Classes

DirectedEdge

Represents a directed edge in a PlanarGraph. A DirectedEdge may or may not have a reference to a parent Edge (some applications of planar graphs may not require explicit Edge objects to be created). Usually a client using a PlanarGraph will subclass DirectedEdge to add its own application-specific data and methods.

DirectedEdgeStar

A sorted collection of DirectedEdges which leave a Node in a PlanarGraph.

Edge

Represents an undirected edge of a {PlanarGraph}. An undirected edge in fact simply acts as a central point of reference for two opposite DirectedEdges. Usually a client using a PlanarGraph will subclass Edge to add its own application-specific data and methods.

GraphComponent

The base class for all graph component classes. Maintains flags of use in generic graph algorithms. Provides two flags: marked - typically this is used to indicate a state that persists for the course of the graph's lifetime. For instance, it can be used to indicate that a component has been logically deleted from the graph. visited - this is used to indicate that a component has been processed or visited by an single graph algorithm. For instance, a breadth-first traversal of the graph might use this to indicate that a node has already been traversed. The visited flag may be set and cleared many times during the lifetime of a graph.

Node

A node in a PlanarGraph is a location where 0 or more Edges meet. A node is connected to each of its incident Edges via an outgoing DirectedEdge. Some clients using a PlanarGraph may want to subclass Node to add their own application-specific data and methods.

NodeMap

A map of nodes, indexed by the coordinate of the node.

PlanarGraph

Represents a directed graph which is embeddable in a planar surface. This class and the other classes in this package serve as a framework for building planar graphs for specific algorithms. This class must be subclassed to expose appropriate methods to construct the graph. This allows controlling the types of graph components ({DirectedEdge}s, Edges and Nodes) which can be added to the graph. An application which uses the graph framework will almost always provide subclasses for one or more graph components, which hold application-specific data and graph algorithms.

Subgraph

A subgraph of a PlanarGraph. A subgraph may contain any subset of Edges from the parent graph. It will also automatically contain all DirectedEdges and Nodes associated with those edges. No new objects are created when edges are added - all associated components must already exist in the parent graph.