distanceutils.java

Local Lucene ==================== Provide geographical based searching to lucene in an efficent ma

/**
 * Copyright 2007 Patrick O'Leary 
 * 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 com.pjaol.search.geo.utils;

import java.awt.geom.Rectangle2D;
import java.text.DecimalFormat;

import org.geotools.referencing.datum.DefaultEllipsoid;

import com.traversetechnologies.fulcrum.math.LonLatTrig;

public class DistanceUtils {

	private static final int coordPrime = 100000000;
	private static final String coordPad = "000000000000";

	private static DefaultEllipsoid de = DefaultEllipsoid.WGS84;
	
	public static double orthodromicDistance(double x1, double y1, double x2, double y2) {
		
		return de.orthodromicDistance(x1, y1, x2, y2);
	 }	

	public static double getDistanceMi(double x1, double y1, double x2, double y2) {
		return  (orthodromicDistance(x1, y1, x2, y2) *0.621371) / 1000;
	}

	/**
	 * 
	 * @param x1
	 * @param y1
	 * @param miles
	 * @return boundary rectangle where getY/getX is top left, getMinY/getMinX is bottom right
	 */
	public static Rectangle2D getBoundary (double x1, double y1, double miles) {
		return LonLatTrig.getRadiusBoundsMi(y1, x1, miles);
	}

	public static Rectangle2D getBoundaryMi (double x1, double y1, double miles){
		return LonLatTrig.getRadiusBoundsMi(y1, x1, miles);
	}
	
	public static Rectangle2D getBoundaryKm (double x1, double y1, double km){
		return LonLatTrig.getRadiusBoundsKm(y1, x1, km);
	}

	/**
	 * convert a padded longitude coord to a double 
	 * @param s
	 * @return
	 */
	public static double stringToLng (String s){
		double x = stringToCood(s);
		return x - 180;
	}

	/**
	 * convert a padded latitude coord to a double 
	 * @param s
	 * @return
	 */
	public static double stringToLat (String s ){
		double x = stringToCood(s);
		return x - 360;
	}

	private static double stringToCood (String s){
		double x;
		try {
			x = new Double(s).doubleValue();
		} catch (Exception e){
			return 0;
		}
		return x / coordPrime;
	}

	/**
	 * convert a longitude to a padded string for searching
	 * @param cord
	 * @return
	 */
	public static String lngToString (double cord) {
		double x = cord + 180;
		return coordToString(x);
	}

	/**
	 * convert a latitude to a padded string for searching
	 * @param cord
	 * @return
	 */
	public static String latToString(double cord){
		double x = cord + 360;
		return coordToString(x);
		
	}

	private static  String coordToString (double coord){
		double x = coord * coordPrime;
		DecimalFormat df  = new DecimalFormat(coordPad);
		return df.format(x);
	}
	
}