GEOS  3.9.0dev
OverlapUnion.h
1 /**********************************************************************
2  *
3  * GEOS - Geometry Engine Open Source
4  * http://trac.osgeo.org/geos
5  *
6  * Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
7  *
8  * This is free software; you can redistribute and/or modify it under
9  * the terms of the GNU Lesser General Public Licence as published
10  * by the Free Software Foundation.
11  * See the COPYING file for more information.
12  *
13  **********************************************************************
14  *
15  * Last port: ORIGINAL WORK, generalization of CascadedPolygonUnion
16  *
17  **********************************************************************/
18 
19 #ifndef GEOS_OP_UNION_OVERLAPUNION_H
20 #define GEOS_OP_UNION_OVERLAPUNION_H
21 
22 #include <geos/export.h>
23 
24 #include <vector>
25 #include <algorithm>
26 #include <unordered_set>
27 
28 #include <geos/geom/Geometry.h>
29 #include <geos/operation/union/UnionStrategy.h>
30 #include <geos/operation/union/CascadedPolygonUnion.h>
31 
32 // Forward declarations
33 namespace geos {
34 namespace geom {
35 class Envelope;
36 class LineSegment;
37 }
38 }
39 
40 namespace geos {
41 namespace operation { // geos::operation
42 namespace geounion { // geos::operation::geounion
43 
95 class GEOS_DLL OverlapUnion {
96 
97 public:
98 
99  OverlapUnion(const geom::Geometry* p_g0, const geom::Geometry* p_g1, geounion::UnionStrategy* unionFun)
100  : g0(p_g0)
101  , g1(p_g1)
102  , unionFunction(unionFun)
103  , geomFactory(p_g0->getFactory())
104  , isUnionSafe(false)
105  {};
106 
107  OverlapUnion(const geom::Geometry* p_g0, const geom::Geometry* p_g1)
108  : OverlapUnion(p_g0, p_g1, &defaultUnionFunction)
109  {};
110 
111 
112  std::unique_ptr<geom::Geometry> doUnion();
113 
114 private:
115 
116  const geom::Geometry* g0;
117  const geom::Geometry* g1;
118  geounion::UnionStrategy* unionFunction;
119  const geom::GeometryFactory* geomFactory;
120  bool isUnionSafe;
121 
122  geounion::ClassicUnionStrategy defaultUnionFunction;
123 
124  geom::Envelope overlapEnvelope(const geom::Geometry* geom0, const geom::Geometry* geom1);
125  std::unique_ptr<geom::Geometry> extractByEnvelope(const geom::Envelope& env, const geom::Geometry* geom, std::vector<std::unique_ptr<geom::Geometry>>& disjointGeoms);
126  std::unique_ptr<geom::Geometry> combine(std::unique_ptr<geom::Geometry>& unionGeom, std::vector<std::unique_ptr<geom::Geometry>>& disjointPolys);
127  std::unique_ptr<geom::Geometry> unionFull(const geom::Geometry* geom0, const geom::Geometry* geom1);
128  std::unique_ptr<geom::Geometry> unionBuffer(const geom::Geometry* geom0, const geom::Geometry* geom1);
129  bool isBorderSegmentsSame(const geom::Geometry* result, const geom::Envelope& env);
130  bool isEqual(std::vector<geom::LineSegment>& segs0, std::vector<geom::LineSegment>& segs1);
131  std::vector<geom::LineSegment> extractBorderSegments(const geom::Geometry* geom0, const geom::Geometry* geom1, const geom::Envelope& env);
132  void extractBorderSegments(const geom::Geometry* geom, const geom::Envelope& penv, std::vector<geom::LineSegment>& psegs);
133 
134 };
135 
136 } // namespace geos::operation::union
137 } // namespace geos::operation
138 } // namespace geos
139 
140 #endif
An Envelope defines a rectangulare region of the 2D coordinate plane.
Definition: Envelope.h:58
Implementation of UnionStrategy that provides overlay using the first generation overlay routines...
Definition: CascadedPolygonUnion.h:59
Definition: UnionStrategy.h:40
Basic implementation of Geometry, constructed and destructed by GeometryFactory.
Definition: Geometry.h:188
Unions MultiPolygons efficiently by using full topological union only for polygons which may overlap ...
Definition: OverlapUnion.h:95
const GeometryFactory * getFactory() const
Gets the factory which contains the context in which this geometry was created.
Definition: Geometry.h:218
Supplies a set of utility methods for building Geometry objects from CoordinateSequence or other Geom...
Definition: GeometryFactory.h:68
Basic namespace for all GEOS functionalities.
Definition: IndexedNestedRingTester.h:26