

PREV PACKAGE NEXT PACKAGE  FRAMES NO FRAMES 
Geometry
s.
See:
Description
Class Summary  
EdgeEndBuilder  Computes the EdgeEnd s which arise from a noded Edge . 
EdgeEndBundle  A collection of EdgeEnd s which obey the following invariant:
They originate at the same node and have the same direction. 
EdgeEndBundleStar  An ordered list of EdgeEndBundle s around a RelateNode . 
RelateComputer  Computes the topological relationship between two Geometries. 
RelateNode  Represents a node in the topological graph used to compute spatial relationships. 
RelateNodeFactory  Used by the NodeMap in a RelateNodeGraph to create RelateNode s. 
RelateNodeGraph  Implements the simple graph of Nodes and EdgeEnd which is all that is required to determine topological relationships between Geometries. 
RelateOp  Implements the SFS relate() operation on two Geometry s. 
Contains classes to implement the computation of the spatial relationships of Geometry
s.
The relate
algorithm computes the IntersectionMatrix
describing the
relationship of two Geometry
s. The algorithm for computing relate
uses the intersection operations supported by topology graphs. Although the relate
result depends on the resultant graph formed by the computed intersections, there is
no need to explicitly compute the entire graph.
It is sufficient to compute the local structure of the graph
at each intersection node.
The algorithm to compute relate
has the following steps:
IntersectionMatrix
from the labels on the nodes and edges.
Geometry
which
do not contain any intersections with the other input Geometry
. The
topological relationship of these components to the other input Geometry
must be computed in order to determine the complete labeling of the component. This can
be done by testing whether the component lies in the interior or exterior of the other
Geometry
. If the other Geometry
is 1dimensional, the isolated
component must lie in the exterior (since otherwise it would have an intersection with an
edge of the Geometry
). If the other Geometry
is 2dimensional,
a PointInPolygon test can be used to determine whether the isolated component is in the
interior or exterior.


PREV PACKAGE NEXT PACKAGE  FRAMES NO FRAMES 