82 lines
2.3 KiB
C
82 lines
2.3 KiB
C
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/**********************************************************************
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*
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* GEOS - Geometry Engine Open Source
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* http://geos.osgeo.org
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*
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* Copyright (C) 2020 Paul Ramsey <pramsey@cleverelephant.ca>
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*
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* This is free software; you can redistribute and/or modify it under
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* the terms of the GNU Lesser General Public Licence as published
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* by the Free Software Foundation.
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* See the COPYING file for more information.
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*
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**********************************************************************/
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#pragma once
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#include <geos/operation/overlayng/OverlayLabel.h>
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#include <geos/operation/overlayng/EdgeKey.h>
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#include <geos/operation/overlayng/Edge.h>
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#include <geos/export.h>
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#include <vector>
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#include <map>
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// Forward declarations
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namespace geos {
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namespace geom {
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class Coordinate;
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}
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namespace operation {
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namespace overlayng {
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class Edge;
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class EdgeKey;
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}
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}
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}
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namespace geos { // geos.
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namespace operation { // geos.operation
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namespace overlayng { // geos.operation.overlayng
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/**
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* Performs merging on the noded edges of the input geometries.
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* Merging takes place on edges which are coincident
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* (i.e. have the same coordinate list, modulo direction).
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* The following situations can occur:
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*
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* - Coincident edges from different input geometries have their labels combined
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* - Coincident edges from the same area geometry indicate a topology collapse.
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* In this case the topology locations are "summed" to provide a final
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* assignment of side location
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* - Coincident edges from the same linear geometry can simply be merged
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* using the same ON location
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*
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* One constraint that is maintained is that the direction of linear
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* edges should be preserved if possible (which is the case if there is
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* no other coincident edge, or if all coincident edges have the same direction).
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* This ensures that the overlay output line direction will be as consistent
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* as possible with input lines.
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*
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* The merger also preserves the order of the edges in the input.
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* This means that for polygon-line overlay
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* the result lines will be in the same order as in the input
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* (possibly with multiple result lines for a single input line).
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*
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* @author mdavis
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*
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*/
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class GEOS_DLL EdgeMerger {
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public:
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static std::vector<Edge*> merge(std::vector<Edge*>& edges);
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};
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} // namespace geos.operation.overlayng
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} // namespace geos.operation
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} // namespace geos
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