Add concave hull of polygons method to Geometry.

Author: jericks

src/main/groovy/geoscript/geom/Geometry.groovy

@@ -3,6 +3,7 @@ package geoscript.geom
 import org.locationtech.jts.algorithm.construct.LargestEmptyCircle
 import org.locationtech.jts.algorithm.construct.MaximumInscribedCircle
 import org.locationtech.jts.algorithm.hull.ConcaveHull
+import org.locationtech.jts.algorithm.hull.ConcaveHullOfPolygons
 import org.locationtech.jts.geom.Geometry as JtsGeometry
 import org.locationtech.jts.geom.GeometryFactory
 import org.locationtech.jts.geom.Coordinate
@@ -144,6 +145,15 @@ class Geometry {
         wrap(ConcaveHull.concaveHullByLength(g, maxLength))
     }
 
+    /**
+     * Calculate the concave hull of polygons
+     * @param maxLength The max length
+     * @return A Geometry
+     */
+    Geometry concaveHullOfPolygons(double maxLength = 0.0) {
+        wrap(ConcaveHullOfPolygons.concaveHullByLength(g, maxLength))
+    }
+
     /**
      * Whether this Geometry is covered by the other Geometry
      * @param The other Geometry

src/test/groovy/geoscript/geom/GeometryTest.groovy

@@ -760,6 +760,17 @@ geometry:
                 "-122.3876953125 47.58121554959838))", concaveHull.wkt)
     }
 
+    @Test void concaveHullOfPolygons() {
+        Geometry geometry = Geometry.fromWKT("MULTIPOLYGON(" +
+                "((-122.38706231117247 47.5819609632087, -122.38846778869627 47.581338579760555, -122.3865258693695 47.58132410563883, -122.3874270915985 47.58065829171401, -122.38551735877991 47.5814398985005, -122.38706231117247 47.5819609632087))," +
+                "((-122.38875210285185 47.580661910290814, -122.3882746696472 47.580661910290814, -122.3882746696472 47.58094415851252, -122.38875210285185 47.58094415851252, -122.38875210285185 47.580661910290814))," +
+                "((-122.38595187664032 47.58192477832709, -122.38551199436188 47.58192477832709, -122.38551199436188 47.582203401270355, -122.38595187664032 47.582203401270355, -122.38595187664032 47.58192477832709))" +
+        ")")
+        Geometry concaveHull = geometry.concaveHullOfPolygons(2.56)
+        assertNotNull(concaveHull)
+        assertEquals("Polygon", concaveHull.getGeometryType())
+    }
+
     @Test void covers() {
 
         Polygon polygon1 = new Polygon([[