Add Coordinates.cast(coordinate,dim,measure) to help with mixed dimen…

…sion operations

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

@@ -15,6 +15,7 @@
  * @version 1.7
  */
 import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Coordinates;
 import org.locationtech.jts.geom.PrecisionModel;
 import org.locationtech.jts.io.WKTWriter;
 import org.locationtech.jts.util.Assert;
@@ -217,10 +218,15 @@ protected boolean isCollinear() {
   public void computeIntersection(
                 Coordinate p1, Coordinate p2,
                 Coordinate p3, Coordinate p4) {
-    inputLines[0][0] = p1;
-    inputLines[0][1] = p2;
-    inputLines[1][0] = p3;
-    inputLines[1][1] = p4;
+
+    int dimension = Coordinates.dimension(p1,p2,p3,p4);
+    int measures = Coordinates.measures(p1,p2,p3,p4);
+
+    inputLines[0][0] = p1 = Coordinates.cast(p1,dimension,measures);
+    inputLines[0][1] = p2 = Coordinates.cast(p2,dimension,measures);
+    inputLines[1][0] = p3 = Coordinates.cast(p3,dimension,measures);
+    inputLines[1][1] = p4 = Coordinates.cast(p4,dimension,measures);
+
     result = computeIntersect(p1, p2, p3, p4);
 //numIntersects++;
   }

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

@@ -215,8 +215,14 @@ private static Coordinate copyWithZInterpolate(Coordinate p, Coordinate p1, Coor
 
   private static Coordinate copyWithZ(Coordinate p, double z) {
     Coordinate pCopy = copy(p);
-    if (! Double.isNaN(z) && Coordinates.hasZ(pCopy)) {
-      pCopy.setZ(z);
+    if (! Double.isNaN(z)) {
+      if (Coordinates.hasZ(pCopy)) {
+        pCopy.setZ(z);
+      }
+      else {
+        // warning: this value cannot be accessed
+        pCopy.z = z;
+      }
     }
     return pCopy;
   }

modules/core/src/main/java/org/locationtech/jts/geom/Coordinates.java

@@ -46,6 +46,39 @@ public static Coordinate create(int dimension, int measures)
     }
     return new Coordinate();
   }
+
+  /**
+   * Cast coordinate to required dimension and measure, only creating a new object if required.
+   * @param coordinate
+   * @param dimension
+   * @param measures
+   * @return coordinate of the requested dimension and measure
+   */
+  public static Coordinate cast( Coordinate coordinate, int dimension, int measures )
+  {
+    if (dimension == 2) {
+      if (coordinate instanceof CoordinateXY)
+        return coordinate;
+      else
+        return new CoordinateXY( coordinate.getX(), coordinate.getY() );
+    } else if (dimension == 3 && measures == 0) {
+      if (coordinate.getClass() == Coordinate.class)
+        return coordinate;
+      else
+        return new Coordinate( coordinate.getX(), coordinate.getY(), coordinate.getZ() );
+    } else if (dimension == 3 && measures == 1) {
+      if (coordinate instanceof CoordinateXYM)
+        return coordinate;
+      else
+        return new CoordinateXYM( coordinate.getX(), coordinate.getY(), coordinate.getM() );
+    } else if (dimension == 4 && measures == 1) {
+      if (coordinate instanceof CoordinateXYZM)
+        return coordinate;
+      else
+        return new CoordinateXYZM(coordinate.getX(), coordinate.getY(), coordinate.getZ(), coordinate.getM() );
+    }
+    return coordinate;
+  }
 
   /**
    * Determine dimension based on subclass of {@link Coordinate}.
@@ -68,7 +101,22 @@ public static int dimension(Coordinate coordinate)
   }
 
   /**
-   * Check if coordinate can store Z valye, based on subclass of {@link Coordinate}.
+   * Determine  dimension based on subclass of {@link Coordinate}.
+   *
+   * @param coordinates supplied coordinate
+   * @return number of ordinates recorded
+   */
+  public static int dimension(Coordinate... coordinates)
+  {
+    int dimension = 2;
+    for (Coordinate coordinate : coordinates) {
+      dimension = Math.max(dimension,dimension(coordinate));
+    }
+    return dimension;
+  }
+
+  /**
+   * Check if coordinate can store Z ordinate, based on subclass of {@link Coordinate}.
    *
    * @param coordinate supplied coordinate
    * @return true if setZ is available
@@ -87,6 +135,26 @@ public static boolean hasZ(Coordinate coordinate)
     return true;
   }
 
+  /**
+   * Check if coordinate can store M value, based on subclass of {@link Coordinate}.
+   *
+   * @param coordinate supplied coordinate
+   * @return true if setM is available
+   */
+  public static boolean hasM(Coordinate coordinate)
+  {
+    if (coordinate instanceof CoordinateXY) {
+      return false;
+    } else if (coordinate instanceof CoordinateXYM) {
+      return true;
+    } else if (coordinate instanceof CoordinateXYZM) {
+      return true;
+    } else if (coordinate instanceof Coordinate) {
+      return false;
+    }
+    return false;
+  }
+
   /**
    * Determine number of measures based on subclass of {@link Coordinate}.
    * 
@@ -106,5 +174,20 @@ public static int measures(Coordinate coordinate)
     } 
     return 0;
   }
-
+
+  /**
+   * Determine  dimension based on subclass of {@link Coordinate}.
+   *
+   * @param coordinates supplied coordinate
+   * @return number of ordinates recorded
+   */
+  public static int measures(Coordinate... coordinates)
+  {
+    int measures = 0;
+    for (Coordinate coordinate : coordinates) {
+      measures = Math.max(measures,measures(coordinate));
+    }
+    return measures;
+  }
+
 }

modules/core/src/test/java/org/locationtech/jts/algorithm/IntersectionTest.java

@@ -85,7 +85,6 @@ public void testIntersectionXY() throws Exception {
     Geometry poly1 = reader.read("POLYGON((0 0 0, 0 10000 2, 10000 10000 2, 10000 0 0, 0 0 0))");
     Geometry clipArea = reader.read("POLYGON((0 0, 0 2500, 2500 2500, 2500 0, 0 0))");
     Geometry clipped1 = poly1.intersection(clipArea);
-    assertNotNull(clipped1);
 
     // intersection with dim 3, dim 2
     GeometryFactory gf = poly1.getFactory();
@@ -111,7 +110,8 @@ public void testIntersectionXY() throws Exception {
 
     Polygon fence = gf.createPolygon(bounds, null);
     Geometry clipped2 = poly1.intersection(fence);
-    assertNotNull(clipped2);
+
+    assertTrue( clipped1.equals(clipped2));
   }
 
   //==================================================