60 lines
1.8 KiB
C
60 lines
1.8 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) 2020-2021 Daniel Baston
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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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#ifndef GEOS_OPERATION_CLUSTER_GEOMETRYDISTANCECLUSTERFINDER
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#define GEOS_OPERATION_CLUSTER_GEOMETRYDISTANCECLUSTERFINDER
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#include <geos/operation/cluster/AbstractClusterFinder.h>
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#include <geos/geom/prep/PreparedGeometry.h>
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#include <geos/geom/prep/PreparedGeometryFactory.h>
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namespace geos {
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namespace operation {
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namespace cluster {
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/** GeometryDistanceClusterFinder clusters geometries according to the distance between
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* them. Any two geometries that are within the specified threshold distance will be
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* included in the same cluster.
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*/
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class GEOS_DLL GeometryDistanceClusterFinder : public AbstractClusterFinder {
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public:
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explicit GeometryDistanceClusterFinder(double distance) : m_distance(distance) {}
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protected:
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bool shouldJoin(const geom::Geometry* a, const geom::Geometry *b) override {
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if (m_prep == nullptr || &(m_prep->getGeometry()) != a) {
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m_prep = geom::prep::PreparedGeometryFactory::prepare(a);
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}
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return m_prep->isWithinDistance(b, m_distance);
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}
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const geom::Envelope& queryEnvelope(const geom::Geometry* a) override {
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m_envelope = *a->getEnvelopeInternal();
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m_envelope.expandBy(m_distance);
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return m_envelope;
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}
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private:
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std::unique_ptr<geom::prep::PreparedGeometry> m_prep;
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double m_distance;
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geom::Envelope m_envelope;
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};
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}
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}
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}
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#endif
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