Merge pull request #66 from geoscript/GSG-65.HPRtree

Add HPRtree spatial index

Author: jericks

src/main/groovy/geoscript/index/HPRtree.groovy

@@ -0,0 +1,26 @@
+package geoscript.index
+
+import org.locationtech.jts.index.hprtree.HPRtree as JtsHPRtree
+
+/**
+ * Create a SpatialIndex using the Hilbert Packed Rtree (HPRtree) spatial index.
+ * <p><blockquote><pre>
+ * def index = new HPRtree()
+ * index.insert(new Bounds(0,0,10,10), new Point(5,5))
+ * index.insert(new Bounds(2,2,6,6), new Point(4,4))
+ *
+ * def results = index.query(new Bounds(1,1,5,5))
+ * </pre></blockquote></p>
+ * @author Jared Erickson
+ */
+class HPRtree extends SpatialIndex {
+
+    /**
+     * Create a SpatialIndex using the HPR Tree spatial index.
+     */
+    HPRtree() {
+        super(new JtsHPRtree())
+    }
+
+}
+

src/test/groovy/geoscript/index/HPRtreeTestCase.groovy

@@ -0,0 +1,36 @@
+package geoscript.index
+
+import geoscript.geom.Bounds
+import geoscript.geom.Point
+import org.junit.Test
+
+import static org.junit.Assert.assertEquals
+import static org.junit.Assert.assertTrue
+
+/**
+ * The HPRtreeTestCase
+ */
+class HPRtreeTestCase {
+
+    @Test void index() {
+
+        def spatialIndex = new HPRtree()
+        spatialIndex.insert(new Bounds(0,0,10,10), new Point(5,5))
+        spatialIndex.insert(new Bounds(2,2,6,6), new Point(4,4))
+        spatialIndex.insert(new Bounds(20,20,60,60), new Point(30,30))
+        spatialIndex.insert(new Bounds(22,22,44,44), new Point(32,32))
+
+        assertEquals 4, spatialIndex.size
+
+        def results = spatialIndex.query(new Bounds(1,1,5,5))
+        assertEquals 2, results.size()
+        assertTrue(results[0].toString() == 'POINT (4 4)' || results[0].toString() == 'POINT (5 5)')
+        assertTrue(results[1].toString() == 'POINT (4 4)' || results[1].toString() == 'POINT (5 5)')
+
+        results = spatialIndex.query(new Bounds(25,25,50,55))
+        assertEquals 2, results.size()
+        assertTrue(results[0].toString() == 'POINT (30 30)' || results[0].toString() == 'POINT (32 32)')
+        assertTrue(results[1].toString() == 'POINT (30 30)' || results[1].toString() == 'POINT (32 32)')
+    }
+}
+