geos::geomgraph::PlanarGraph Class Reference

Represents a directed graph which is embeddable in a planar surface. More...

#include <PlanarGraph.h>

Inherited by geos::geomgraph::GeometryGraph.

List of all members.

Public Member Functions

 PlanarGraph (const NodeFactory &nodeFact)
virtual std::vector< Edge * >
::iterator 
getEdgeIterator ()
virtual std::vector< EdgeEnd * > * getEdgeEnds ()
virtual bool isBoundaryNode (int geomIndex, const geom::Coordinate &coord)
virtual void add (EdgeEnd *e)
virtual NodeMap::iterator getNodeIterator ()
virtual void getNodes (std::vector< Node * > &)
virtual Node * addNode (Node *node)
virtual Node * addNode (const geom::Coordinate &coord)
virtual Node * find (geom::Coordinate &coord)
 
Returns:
the node if found; null otherwise

virtual void addEdges (const std::vector< Edge * > &edgesToAdd)
 Add a set of edges to the graph. For each edge two DirectedEdges will be created. DirectedEdges are NOT linked by this method.
virtual void linkResultDirectedEdges ()
virtual void linkAllDirectedEdges ()
virtual EdgeEndfindEdgeEnd (Edge *e)
 Returns the EdgeEnd which has edge e as its base edge (MD 18 Feb 2002 - this should return a pair of edges).
virtual Edge * findEdge (const geom::Coordinate &p0, const geom::Coordinate &p1)
 Returns the edge whose first two coordinates are p0 and p1.
virtual Edge * findEdgeInSameDirection (const geom::Coordinate &p0, const geom::Coordinate &p1)
 Returns the edge which starts at p0 and whose first segment is parallel to p1.
virtual std::string printEdges ()
virtual NodeMap * getNodeMap ()

Static Public Member Functions

static void linkResultDirectedEdges (std::vector< Node * >::iterator start, std::vector< Node * >::iterator end)
 For nodes in the vector, link the DirectedEdges at the node that are in the result.

Protected Member Functions

virtual void insertEdge (Edge *e)

Protected Attributes

std::vector< Edge * > * edges
NodeMap * nodes
std::vector< EdgeEnd * > * edgeEndList


Detailed Description

Represents a directed graph which is embeddable in a planar surface.

The computation of the IntersectionMatrix relies on the use of a structure called a "topology graph". The topology graph contains nodes and edges corresponding to the nodes and line segments of a Geometry. Each node and edge in the graph is labeled with its topological location relative to the source geometry.

Note that there is no requirement that points of self-intersection be a vertex. Thus to obtain a correct topology graph, Geometry objects must be self-noded before constructing their graphs.

Two fundamental operations are supported by topology graphs:


Member Function Documentation

static void geos::geomgraph::PlanarGraph::linkResultDirectedEdges ( std::vector< Node * >::iterator  start,
std::vector< Node * >::iterator  end 
) [static]

For nodes in the vector, link the DirectedEdges at the node that are in the result.

This allows clients to link only a subset of nodes in the graph, for efficiency (because they know that only a subset is of interest).

virtual EdgeEnd* geos::geomgraph::PlanarGraph::findEdgeEnd ( Edge *  e  )  [virtual]

Returns the EdgeEnd which has edge e as its base edge (MD 18 Feb 2002 - this should return a pair of edges).

Returns:
the edge, if found null if the edge was not found

virtual Edge* geos::geomgraph::PlanarGraph::findEdge ( const geom::Coordinate p0,
const geom::Coordinate p1 
) [virtual]

Returns the edge whose first two coordinates are p0 and p1.

Returns:
the edge, if found null if the edge was not found

virtual Edge* geos::geomgraph::PlanarGraph::findEdgeInSameDirection ( const geom::Coordinate p0,
const geom::Coordinate p1 
) [virtual]

Returns the edge which starts at p0 and whose first segment is parallel to p1.

Returns:
the edge, if found null if the edge was not found


The documentation for this class was generated from the following file:
Generated on Fri Mar 27 04:53:34 2009 for GEOS by  doxygen 1.5.4