122 lines
3.6 KiB
C++
122 lines
3.6 KiB
C++
/**********************************************************************
|
|
*
|
|
* GEOS - Geometry Engine Open Source
|
|
* http://geos.osgeo.org
|
|
*
|
|
* Copyright (C) 2020 Paul Ramsey <pramsey@cleverelephant.ca>
|
|
*
|
|
* This is free software; you can redistribute and/or modify it under
|
|
* the terms of the GNU Lesser General Public Licence as published
|
|
* by the Free Software Foundation.
|
|
* See the COPYING file for more information.
|
|
*
|
|
**********************************************************************
|
|
*
|
|
* Last port: noding/snap/SnappingNoder.java
|
|
*
|
|
**********************************************************************/
|
|
|
|
#pragma once
|
|
|
|
#include <geos/export.h>
|
|
|
|
#include <geos/geom/Coordinate.h>
|
|
#include <geos/geom/CoordinateSequence.h>
|
|
#include <geos/geom/Envelope.h>
|
|
#include <geos/noding/Noder.h>
|
|
#include <geos/noding/snap/SnappingPointIndex.h>
|
|
|
|
|
|
// Forward declarations
|
|
namespace geos {
|
|
namespace geom {
|
|
class Envelope;
|
|
class PrecisionModel;
|
|
}
|
|
namespace noding {
|
|
class NodedSegmentString;
|
|
}
|
|
}
|
|
|
|
namespace geos {
|
|
namespace noding { // geos::noding
|
|
namespace snap { // geos::noding::snap
|
|
|
|
/**
|
|
* Nodes a set of segment strings
|
|
* snapping vertices and intersection points together if
|
|
* they lie within the given snap tolerance distance.
|
|
* Vertices take priority over intersection points for snapping.
|
|
* Input segment strings are generally only split at true node points
|
|
* (i.e. the output segment strings are of maximal length in the output arrangement).
|
|
*
|
|
* The snap tolerance should be chosen to be as small as possible
|
|
* while still producing a correct result.
|
|
* It probably only needs to be small enough to eliminate
|
|
* "nearly-coincident" segments, for which intersection points cannot be computed accurately.
|
|
* This implies a factor of about 10e-12
|
|
* smaller than the magnitude of the segment coordinates.
|
|
*
|
|
* With an appropriate snap tolerance this algorithm appears to be very robust.
|
|
* So far no failure cases have been found,
|
|
* given a small enough snap tolerance.
|
|
*
|
|
* The correctness of the output is not verified by this noder.
|
|
* If required this can be done by {@link noding::ValidatingNoder}.
|
|
*/
|
|
class GEOS_DLL SnappingNoder : public Noder {
|
|
|
|
private:
|
|
|
|
// Members
|
|
double snapTolerance;
|
|
SnappingPointIndex snapIndex;
|
|
std::vector<SegmentString*>* nodedResult;
|
|
|
|
// Methods
|
|
|
|
void seedSnapIndex(std::vector<SegmentString*>& segStrings);
|
|
|
|
void snapVertices(std::vector<SegmentString*>& segStrings, std::vector<SegmentString*>& nodedStrings);
|
|
|
|
SegmentString* snapVertices(SegmentString* ss);
|
|
|
|
std::unique_ptr<geom::CoordinateSequence> snap(const geom::CoordinateSequence* cs);
|
|
|
|
/**
|
|
* Computes all interior intersections in the collection of {@link SegmentString}s,
|
|
* and returns their {@link Coordinate}s.
|
|
*
|
|
* Also adds the intersection nodes to the segments.
|
|
*
|
|
* @return a list of Coordinates for the intersections
|
|
*/
|
|
std::unique_ptr<std::vector<SegmentString*>> snapIntersections(std::vector<SegmentString*>& inputSS);
|
|
|
|
|
|
public:
|
|
|
|
/**
|
|
* Creates a snapping noder using the given snap distance tolerance.
|
|
* @param p_snapTolerance points are snapped if within this distance
|
|
*/
|
|
SnappingNoder(double p_snapTolerance)
|
|
: snapTolerance(p_snapTolerance)
|
|
, snapIndex(p_snapTolerance)
|
|
{}
|
|
|
|
/**
|
|
* @return a Collection of NodedSegmentStrings representing the substrings
|
|
*/
|
|
std::vector<SegmentString*>* getNodedSubstrings() const override;
|
|
|
|
void computeNodes(std::vector<SegmentString*>* inputSegStrings) override;
|
|
|
|
|
|
};
|
|
|
|
|
|
} // namespace geos::noding::snap
|
|
} // namespace geos::noding
|
|
} // namespace geos
|