include/geos/opRelate.h

   1 /**********************************************************************
   2  *
   3  * GEOS - Geometry Engine Open Source
   4  * http://geos.osgeo.org
   5  *
   6  * Copyright (C) 2001-2002 Vivid Solutions Inc.
   7  * Copyright (C) 2005 Refractions Research Inc.
   8  *
   9  * This is free software; you can redistribute and/or modify it under
  10  * the terms of the GNU Lesser General Public Licence as published
  11  * by the Free Software Foundation.
  12  * See the COPYING file for more information.
  13  *
  14  **********************************************************************/
  15
  16 #ifndef GEOS_OPRELATE_H
  17 #define GEOS_OPRELATE_H
  18
  19 namespace geos {
  20 namespace operation { // geos::operation
  21
  22
  23 /** \brief
  24  * Contains classes to implement the computation of the spatial relationships of <CODE>Geometry</CODE>s.
  25  *
  26  * The <code>relate</code> algorithm computes the <code>IntersectionMatrix</code> describing the
  27  * relationship of two <code>Geometry</code>s.  The algorithm for computing <code>relate</code>
  28  * uses the intersection operations supported by topology graphs.  Although the <code>relate</code>
  29  * result depends on the resultant graph formed by the computed intersections, there is
  30  * no need to explicitly compute the entire graph.
  31  * It is sufficient to compute the local structure of the graph
  32  * at each intersection node.
  33  * <P>
  34  * The algorithm to compute <code>relate</code> has the following steps:
  35  * <UL>
  36  *   <LI>Build topology graphs of the two input geometries. For each geometry
  37  *       all self-intersection nodes are computed and added to the graph.
  38  *   <LI>Compute nodes for all intersections between edges and nodes of the graphs.
  39  *   <LI>Compute the labeling for the computed nodes by merging the labels from the input graphs.
  40  *   <LI>Compute the labeling for isolated components of the graph (see below)
  41  *   <LI>Compute the <code>IntersectionMatrix</code> from the labels on the nodes and edges.
  42  * </UL>
  43  *
  44  * <H3>Labeling isolated components</H3>
  45  *
  46  * Isolated components are components (edges or nodes) of an input <code>Geometry</code> which
  47  * do not contain any intersections with the other input <code>Geometry</code>.  The
  48  * topological relationship of these components to the other input <code>Geometry</code>
  49  * must be computed in order to determine the complete labeling of the component.  This can
  50  * be done by testing whether the component lies in the interior or exterior of the other
  51  * <code>Geometry</code>.  If the other <code>Geometry</code> is 1-dimensional, the isolated
  52  * component must lie in the exterior (since otherwise it would have an intersection with an
  53  * edge of the <code>Geometry</code>).  If the other <code>Geometry</code> is 2-dimensional,
  54  * a Point-In-Polygon test can be used to determine whether the isolated component is in the
  55  * interior or exterior.
  56  *
  57  * <h2>Package Specification</h2>
  58  *
  59  * <ul>
  60  *   <li>Java Topology Suite Technical Specifications
  61  *   <li><A HREF="http://www.opengis.org/techno/specs.htm">
  62  *       OpenGIS Simple Features Specification for SQL</A>
  63  * </ul>
  64  *
  65  */
  66 namespace relate { // geos.operation.relate
  67
  68 } // namespace geos:operation:relate
  69 } // namespace geos:operation
  70 } // namespace geos
  71
  72
  73 //#include <geos/operation/relate/EdgeEndBuilder.h>
  74 //#include <geos/operation/relate/EdgeEndBundle.h>
  75 //#include <geos/operation/relate/EdgeEndBundleStar.h>
  76 #include <geos/operation/relate/RelateComputer.h>
  77 //#include <geos/operation/relate/RelateNode.h>
  78 //#include <geos/operation/relate/RelateNodeFactory.h>
  79 //#include <geos/operation/relate/RelateNodeGraph.h>
  80 #include <geos/operation/relate/RelateOp.h>
  81
  82 #endif
  83