/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 com.spatial4j.core.distance;
import com.spatial4j.core.context.SpatialContext;
import com.spatial4j.core.shape.Circle;
import com.spatial4j.core.shape.Point;
import com.spatial4j.core.shape.Rectangle;
import static com.spatial4j.core.distance.DistanceUtils.toDegrees;
import static com.spatial4j.core.distance.DistanceUtils.toRadians;
/**
* A base class for a Distance Calculator that assumes a spherical earth model.
*/
public abstract class GeodesicSphereDistCalc extends AbstractDistanceCalculator {
private static final double radiusDEG = DistanceUtils.toDegrees(1);//in degrees
@Override
public Point pointOnBearing(Point from, double distDEG, double bearingDEG, SpatialContext ctx, Point reuse) {
if (distDEG == 0) {
if (reuse == null)
return from;
reuse.reset(from.getX(), from.getY());
return reuse;
}
Point result = DistanceUtils.pointOnBearingRAD(
toRadians(from.getY()), toRadians(from.getX()),
toRadians(distDEG),
toRadians(bearingDEG), ctx, reuse);//output result is in radians
result.reset(toDegrees(result.getX()), toDegrees(result.getY()));
return result;
}
@Override
public Rectangle calcBoxByDistFromPt(Point from, double distDEG, SpatialContext ctx, Rectangle reuse) {
return DistanceUtils.calcBoxByDistFromPtDEG(from.getY(), from.getX(), distDEG, ctx, reuse);
}
@Override
public double calcBoxByDistFromPt_yHorizAxisDEG(Point from, double distDEG, SpatialContext ctx) {
return DistanceUtils.calcBoxByDistFromPt_latHorizAxisDEG(from.getY(), from.getX(), distDEG);
}
@Override
public double area(Rectangle rect) {
//From http://mathforum.org/library/drmath/view/63767.html
double lat1 = toRadians(rect.getMinY());
double lat2 = toRadians(rect.getMaxY());
return Math.PI / 180 * radiusDEG * radiusDEG *
Math.abs(Math.sin(lat1) - Math.sin(lat2)) *
rect.getWidth();
}
@Override
public double area(Circle circle) {
//formula is a simplified case of area(rect).
double lat = toRadians(90 - circle.getRadius());
return 2 * Math.PI * radiusDEG * radiusDEG * (1 - Math.sin(lat));
}
@Override
public boolean equals(Object obj) {
if (obj == null)
return false;
return getClass().equals(obj.getClass());
}
@Override
public int hashCode() {
return getClass().hashCode();
}
@Override
public final double distance(Point from, double toX, double toY) {
return toDegrees(distanceLatLonRAD(toRadians(from.getY()), toRadians(from.getX()), toRadians(toY), toRadians(toX)));
}
protected abstract double distanceLatLonRAD(double lat1, double lon1, double lat2, double lon2);
public static class Haversine extends GeodesicSphereDistCalc {
@Override
protected double distanceLatLonRAD(double lat1, double lon1, double lat2, double lon2) {
return DistanceUtils.distHaversineRAD(lat1,lon1,lat2,lon2);
}
}
public static class LawOfCosines extends GeodesicSphereDistCalc {
@Override
protected double distanceLatLonRAD(double lat1, double lon1, double lat2, double lon2) {
return DistanceUtils.distLawOfCosinesRAD(lat1, lon1, lat2, lon2);
}
}
public static class Vincenty extends GeodesicSphereDistCalc {
@Override
protected double distanceLatLonRAD(double lat1, double lon1, double lat2, double lon2) {
return DistanceUtils.distVincentyRAD(lat1, lon1, lat2, lon2);
}
}
}