Add GEOSCoverageUnion

.travis.yml

@@ -6,7 +6,7 @@
 # by the Free Software Foundation.
 # See the COPYING file for more information.
 #
-dist: trusty
+dist: xenial
 sudo: false
 
 language: cpp

NEWS

@@ -5,11 +5,14 @@ Changes in 3.8.0
   - CAPI: GEOSBuildArea (#952, Even Rouault)
   - CAPI: GEOSMakeValid (#952, Even Rouault)
   - CAPI: GEOSPolygonize_valid (#727, Dan Baston)
+  - CAPI: GEOSCoverageUnion (Dan Baston)
 
 - Improvements:
   - Improve performance and robustness of GEOSPointOnSurface (Martin Davis)
   - Improve performance of GEOSPolygonize for cases with many potential
     holes (#748, Dan Baston)
+  - Improve performance of GEOSPolygonize for cases with many or complex
+    shells (Dan Baston, Martin Davis)
 
 
 Changes in 3.7.2

capi/geos_c.cpp

@@ -505,6 +505,12 @@ extern "C" {
         return GEOSUnaryUnion_r(handle, g);
     }
 
+    Geometry*
+    GEOSCoverageUnion(const Geometry* g)
+    {
+        return GEOSCoverageUnion_r(handle, g);
+    }
+
     Geometry*
     GEOSNode(const Geometry* g)
     {

capi/geos_c.h.in

@@ -572,6 +572,11 @@ extern GEOSGeometry GEOS_DLL *GEOSUnion_r(GEOSContextHandle_t handle,
                                           const GEOSGeometry* g2);
 extern GEOSGeometry GEOS_DLL *GEOSUnaryUnion_r(GEOSContextHandle_t handle,
                                           const GEOSGeometry* g);
+/* GEOSCoverageUnion is an optimized union algorithm for polygonal inputs that are correctly
+ * noded and do not overlap. It will not generate an error (return NULL) for inputs that
+ * do not satisfy this constraint. */
+extern GEOSGeometry GEOS_DLL *GEOSCoverageUnion_r(GEOSContextHandle_t handle,
+                                                  const GEOSGeometry* g);
 /* @deprecated in 3.3.0: use GEOSUnaryUnion_r instead */
 extern GEOSGeometry GEOS_DLL *GEOSUnionCascaded_r(GEOSContextHandle_t handle,
                                                   const GEOSGeometry* g);
@@ -1603,6 +1608,11 @@ extern GEOSGeometry GEOS_DLL *GEOSBoundary(const GEOSGeometry* g);
 extern GEOSGeometry GEOS_DLL *GEOSUnion(const GEOSGeometry* g1, const GEOSGeometry* g2);
 extern GEOSGeometry GEOS_DLL *GEOSUnaryUnion(const GEOSGeometry* g);
 
+/* GEOSCoverageUnion is an optimized union algorithm for polygonal inputs that are correctly
+ * noded and do not overlap. It will not generate an error (return NULL) for inputs that
+ * do not satisfy this constraint. */
+extern GEOSGeometry GEOS_DLL *GEOSCoverageUnion(const GEOSGeometry *g);
+
 /* @deprecated in 3.3.0: use GEOSUnaryUnion instead */
 extern GEOSGeometry GEOS_DLL *GEOSUnionCascaded(const GEOSGeometry* g);
 extern GEOSGeometry GEOS_DLL *GEOSPointOnSurface(const GEOSGeometry* g);

capi/geos_ts_c.cpp

@@ -67,6 +67,7 @@
 #include <geos/operation/relate/RelateOp.h>
 #include <geos/operation/sharedpaths/SharedPathsOp.h>
 #include <geos/operation/union/CascadedPolygonUnion.h>
+#include <geos/operation/union/CoverageUnion.h>
 #include <geos/operation/valid/IsValidOp.h>
 #include <geos/operation/valid/MakeValid.h>
 #include <geos/precision/GeometryPrecisionReducer.h>
@@ -2145,6 +2146,32 @@ extern "C" {
         return NULL;
     }
 
+    Geometry*
+    GEOSCoverageUnion_r(GEOSContextHandle_t extHandle, const Geometry* g)
+    {
+        if(0 == extHandle) {
+            return NULL;
+        }
+
+        GEOSContextHandleInternal_t* handle = 0;
+        handle = reinterpret_cast<GEOSContextHandleInternal_t*>(extHandle);
+        if(0 == handle->initialized) {
+            return NULL;
+        }
+
+        try {
+            return geos::operation::geounion::CoverageUnion::Union(g).release();
+        }
+        catch(const std::exception& e) {
+            handle->ERROR_MESSAGE("%s", e.what());
+        }
+        catch(...) {
+            handle->ERROR_MESSAGE("Unknown exception thrown");
+        }
+
+        return NULL;
+    }
+
     Geometry*
     GEOSUnaryUnion_r(GEOSContextHandle_t extHandle, const Geometry* g)
     {

include/geos/geom/LineSegment.h

@@ -27,6 +27,7 @@
 #include <geos/inline.h>
 
 #include <iostream> // for ostream
+#include <functional> // for std::hash
 #include <memory> // for unique_ptr
 
 // Forward declarations
@@ -366,6 +367,14 @@ class GEOS_DLL LineSegment {
      */
     std::unique_ptr<LineString> toGeometry(const GeometryFactory& gf) const;
 
+    struct HashCode {
+        size_t operator()(const LineSegment & s) const {
+            size_t h = std::hash<double>{}(s.p0.x);
+            h ^= (std::hash<double>{}(s.p0.y) << 1);
+            h ^= (std::hash<double>{}(s.p1.x) << 1);
+            return h ^ (std::hash<double>{}(s.p1.y) << 1);
+        }
+    };
 };
 
 std::ostream& operator<< (std::ostream& o, const LineSegment& l);