Fix some algorithms handling of XYZM coordinates

modules/core/src/main/java/org/locationtech/jts/algorithm/Area.java

@@ -93,9 +93,9 @@ public static double ofRingSigned(CoordinateSequence ring)
      * Based on the Shoelace formula.
      * http://en.wikipedia.org/wiki/Shoelace_formula
      */
-    Coordinate p0 = new Coordinate();
-    Coordinate p1 = new Coordinate();
-    Coordinate p2 = new Coordinate();
+    Coordinate p0 = ring.createCoordinate();
+    Coordinate p1 = ring.createCoordinate();
+    Coordinate p2 = ring.createCoordinate();
     ring.getCoordinate(0, p1);
     ring.getCoordinate(1, p2);
     double x0 = p1.x;

modules/core/src/main/java/org/locationtech/jts/algorithm/Length.java

@@ -37,7 +37,7 @@ public static double ofLine(CoordinateSequence pts)
 
     double len = 0.0;
 
-    Coordinate p = new Coordinate();
+    Coordinate p = pts.createCoordinate();
     pts.getCoordinate(0, p);
     double x0 = p.x;
     double y0 = p.y;

modules/core/src/test/java/org/locationtech/jts/geom/GeometryXYZMTest.java

@@ -0,0 +1,37 @@
+package org.locationtech.jts.geom;
+
+import org.locationtech.jts.geom.impl.PackedCoordinateSequenceFactory;
+import org.locationtech.jts.io.ParseException;
+
+import junit.textui.TestRunner;
+import test.jts.GeometryTestCase;
+
+/**
+ * Tests to confirm that operations call {@link CoordinateSequence#createCoordinate()}
+ * to ensure they work correctly with coordinates of any dimension
+ * (in particular XYZM coordinates, which do not fit in the default {@link Coordinate}).
+ * 
+ * @author Martin Davis
+ *
+ */
+public class GeometryXYZMTest extends GeometryTestCase {
+  public static void main(String args[]) {
+    TestRunner.run(GeometryXYZMTest.class);
+  }
+
+  static GeometryFactory geomFact = new GeometryFactory(PackedCoordinateSequenceFactory.DOUBLE_FACTORY);
+
+  public GeometryXYZMTest(String name) { super(name); }
+
+  public void testArea() {
+    Polygon geom = (Polygon) read(geomFact, "POLYGON ZM ((1 9 2 3, 9 9 2 3, 9 1 2 3, 1 1 2 3, 1 9 2 3))");
+    double area = geom.getArea();
+    assertEquals(64.0, area);
+  }
+
+  public void testLength() {
+    Polygon geom = (Polygon) read(geomFact, "POLYGON ZM ((1 9 2 3, 9 9 2 3, 9 1 2 3, 1 1 2 3, 1 9 2 3))");
+    double len = geom.getLength();
+    assertEquals(32.0, len);
+  }
+}