public class PlanarGraph extends Object
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
s must be
self-noded before constructing their graphs.
Two fundamental operations are supported by topology graphs:
Constructor and Description |
---|
PlanarGraph() |
PlanarGraph(NodeFactory nodeFact) |
Modifier and Type | Method and Description |
---|---|
void |
add(EdgeEnd e) |
void |
addEdges(List edgesToAdd)
Add a set of edges to the graph.
|
Node |
addNode(Coordinate coord) |
Node |
addNode(Node node) |
Node |
find(Coordinate coord)
Find coordinate.
|
Edge |
findEdge(Coordinate p0,
Coordinate p1)
Returns the edge whose first two coordinates are p0 and p1
|
EdgeEnd |
findEdgeEnd(Edge e)
Returns the EdgeEnd which has edge e as its base edge
(MD 18 Feb 2002 - this should return a pair of edges)
|
Edge |
findEdgeInSameDirection(Coordinate p0,
Coordinate p1)
Returns the edge which starts at p0 and whose first segment is
parallel to p1
|
Collection |
getEdgeEnds() |
Iterator |
getEdgeIterator() |
Iterator |
getNodeIterator() |
Collection |
getNodes() |
boolean |
isBoundaryNode(int geomIndex,
Coordinate coord) |
void |
linkAllDirectedEdges()
Link the DirectedEdges at the nodes of the graph.
|
void |
linkResultDirectedEdges()
Link the DirectedEdges at the nodes of the graph.
|
static void |
linkResultDirectedEdges(Collection nodes)
For nodes in the Collection, link the DirectedEdges at the node that are in the result.
|
void |
printEdges(PrintStream out) |
public PlanarGraph(NodeFactory nodeFact)
public PlanarGraph()
public static void linkResultDirectedEdges(Collection nodes)
nodes
- Collection of nodespublic Iterator getEdgeIterator()
public Collection getEdgeEnds()
public boolean isBoundaryNode(int geomIndex, Coordinate coord)
public void add(EdgeEnd e)
public Iterator getNodeIterator()
public Collection getNodes()
public Node addNode(Coordinate coord)
public Node find(Coordinate coord)
coord
- Coordinate to findpublic void addEdges(List edgesToAdd)
edgesToAdd
- Set of edges to add to the graphpublic void linkResultDirectedEdges()
public void linkAllDirectedEdges()
public EdgeEnd findEdgeEnd(Edge e)
e
- Edgenull
if the edge was not foundpublic Edge findEdge(Coordinate p0, Coordinate p1)
p0
- first coordinate to matchp1
- second coordinate to matchnull
if the edge was not foundpublic Edge findEdgeInSameDirection(Coordinate p0, Coordinate p1)
p0
- Starting coordinatep1
- Coordinate used to establish directionnull
if the edge was not foundpublic void printEdges(PrintStream out)
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