EMPTY points in JTS are now convertible to a Shape instead of throwin…

…g an exception.

Fixes #163

CHANGES.md

@@ -1,13 +1,14 @@
 ## VERSION 0.8
 
-DATE: March 8 2020
+DATE: unreleased
 
 * \#177: Improve conversion of a Circle to Shape. JtsShapeFactory allows converting from a Shape
   object to a JTS Geometry object. Geodetic circles now translate to a polygon that has points
   equidistant from the center. Before the change, there was potentially a large inaccuracy.
   (Hrishi Bakshi)
-
----------------------------------------
+
+* \#163: EMPTY points in JTS are now convertible to a Spatial4j Shape instead of throwing an exception.
+  (David Smiley)
 
 ## VERSION 0.7
 

src/main/java/org/locationtech/spatial4j/shape/jts/JtsShapeFactory.java

@@ -479,7 +479,11 @@ public Shape makeShapeFromGeometry(Geometry geom) {
       }
     } else if (geom instanceof org.locationtech.jts.geom.Point) {
       org.locationtech.jts.geom.Point pt = (org.locationtech.jts.geom.Point) geom;
-      return pointXY(pt.getX(), pt.getY());
+      if (pt.isEmpty()) {
+        return pointXY(Double.NaN, Double.NaN);
+      } else {
+        return pointXY(pt.getX(), pt.getY());
+      }
     } else if (geom instanceof LineString) {
       if (!useJtsLineString()) {
         LineString lineString = (LineString) geom;

src/test/java/org/locationtech/spatial4j/shape/jts/JtsShapeFactoryTest.java

@@ -18,16 +18,18 @@
 package org.locationtech.spatial4j.shape.jts;
 
 import org.junit.Assert;
+import org.junit.Test;
 import org.locationtech.jts.geom.Coordinate;
 import org.locationtech.jts.geom.Geometry;
-import org.junit.Test;
+import org.locationtech.jts.geom.GeometryFactory;
 import org.locationtech.jts.geom.Polygon;
 import org.locationtech.spatial4j.context.SpatialContext;
 import org.locationtech.spatial4j.context.jts.JtsSpatialContext;
 import org.locationtech.spatial4j.context.jts.JtsSpatialContextFactory;
 import org.locationtech.spatial4j.distance.DistanceUtils;
 import org.locationtech.spatial4j.distance.GeodesicSphereDistCalc;
 import org.locationtech.spatial4j.shape.Point;
+import org.locationtech.spatial4j.shape.Shape;
 import org.locationtech.spatial4j.shape.impl.GeoCircle;
 import org.locationtech.spatial4j.shape.impl.PointImpl;
 
@@ -52,6 +54,16 @@ public void testIndex() {
     assertTrue(jtsGeom2.isIndexed());
   }
 
+  @Test
+  public void testEmptyPoint() {
+    JtsSpatialContextFactory jtsCtxFactory = new JtsSpatialContextFactory();
+    JtsSpatialContext jtsCtx = jtsCtxFactory.newSpatialContext();
+    GeometryFactory geometryFactory = jtsCtxFactory.getGeometryFactory();
+    final org.locationtech.jts.geom.Point  point = geometryFactory.createPoint();//empty
+    final Shape shape = jtsCtx.getShapeFactory().makeShapeFromGeometry(point); // don't throw
+    assertTrue(shape.isEmpty());
+  }
+
   @Test
   public void testCircleGeometryConversions() {
     // Hawaii (Far West)