--- /dev/null
+/*
+ * Copyright 2006 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.wamblee.gpx;
+
+/**
+ * Reference coordinate system which is the basis for defining metrics.
+ * This is a Cartesian coordinate system.
+ */
+public class ReferenceCoordinateSystem implements CoordinateSystem {
+
+ /**
+ * Constructs the coordinate system.
+ *
+ */
+ public ReferenceCoordinateSystem() {
+ // Empty
+ }
+
+ /*
+ * (non-Javadoc)
+ *
+ * @see org.wamblee.gpx.CoordinateSystem#toReferenceSystem(org.wamblee.gpx.Coordinates)
+ */
+ public Coordinates toReferenceSystem(Coordinates aCoordinates) {
+ return aCoordinates;
+ }
+
+ /*
+ * (non-Javadoc)
+ *
+ * @see org.wamblee.gpx.CoordinateSystem#distance(org.wamblee.gpx.Coordinates,
+ * org.wamblee.gpx.Coordinates)
+ */
+ private static double distance(Coordinates aC1, Coordinates aC2) {
+ return Math.sqrt(square(aC1.getX1() - aC2.getX1())
+ + square(aC1.getX2() - aC2.getX2())
+ + square(aC1.getX3() - aC2.getX3()));
+ }
+
+ private static double square(double x) {
+ return x * x;
+ }
+
+ /**
+ * Computes the distance between two points in arbitrary coordinate systems.
+ * @param aP1 First point.
+ * @param aP2 Second point.
+ * @return Distance.
+ */
+ public static double distance(Point aP1, Point aP2) {
+ return distance( aP1.getCoordinateSystem().toReferenceSystem(aP1.getCoordinates()),
+ aP2.getCoordinateSystem().toReferenceSystem(aP2.getCoordinates()));
+ }
+
+}