src/algorithm/CentroidLine.cpp

   1 /**********************************************************************
   2  * $Id$
   3  *
   4  * GEOS - Geometry Engine Open Source
   5  * http://geos.refractions.net
   6  *
   7  * Copyright (C) 2001-2002 Vivid Solutions Inc.
   8  * Copyright (C) 2005 Refractions Research Inc.
   9  *
  10  * This is free software; you can redistribute and/or modify it under
  11  * the terms of the GNU Lesser General Public Licence as published
  12  * by the Free Software Foundation.
  13  * See the COPYING file for more information.
  14  *
  15  **********************************************************************
  16  *
  17  **********************************************************************/
  18
  19 #include <geos/algorithm/CentroidLine.h>
  20 #include <geos/geom/Coordinate.h>
  21 #include <geos/geom/CoordinateSequence.h>
  22 #include <geos/geom/Geometry.h>
  23 #include <geos/geom/GeometryCollection.h>
  24 #include <geos/geom/LineString.h>
  25
  26 #include <typeinfo>
  27
  28 using namespace geos::geom;
  29
  30 namespace geos {
  31 namespace algorithm { // geos.algorithm
  32
  33 /*public*/
  34 void
  35 CentroidLine::add(const Geometry *geom)
  36 {
  37         const LineString* ls = dynamic_cast<const LineString*>(geom);
  38         if ( ls )
  39         {
  40                 add(ls->getCoordinatesRO());
  41                 return;
  42         }
  43
  44         const GeometryCollection* gc = dynamic_cast<const GeometryCollection*>(geom);
  45         if (gc)
  46         {
  47         for(std::size_t i=0, n=gc->getNumGeometries(); i<n; i++) {
  48                         add(gc->getGeometryN(i));
  49                 }
  50         }
  51 }
  52
  53 /*public*/
  54 void
  55 CentroidLine::add(const CoordinateSequence *pts)
  56 {
  57         std::size_t const npts=pts->getSize();
  58
  59         for(std::size_t i=1; i<npts; ++i)
  60         {
  61                 const Coordinate &p1=pts->getAt(i-1);
  62                 const Coordinate &p2=pts->getAt(i);
  63
  64                 double segmentLen=p1.distance(p2);
  65                 totalLength+=segmentLen;
  66                 double midx=(p1.x+p2.x)/2;
  67                 centSum.x+=segmentLen*midx;
  68                 double midy=(p1.y+p2.y)/2;
  69                 centSum.y+=segmentLen*midy;
  70         }
  71 }
  72
  73 Coordinate *
  74 CentroidLine::getCentroid() const
  75 {
  76         return new Coordinate(centSum.x/totalLength, centSum.y/totalLength);
  77 }
  78
  79 bool
  80 CentroidLine::getCentroid(Coordinate& c) const
  81 {
  82         if ( totalLength == 0.0 ) return false;
  83         c=Coordinate(centSum.x/totalLength, centSum.y/totalLength);
  84         return true;
  85 }
  86
  87 } // namespace geos.algorithm
  88 } // namespace geos
  89
  90 /**********************************************************************
  91  * $Log$
  92  * Revision 1.16  2006/03/21 11:12:23  strk
  93  * Cleanups: headers inclusion and Log section
  94  *
  95  * Revision 1.15  2006/03/09 16:46:45  strk
  96  * geos::geom namespace definition, first pass at headers split
  97  *
  98  **********************************************************************/
  99