GeoPoint.java

/* 
This file is part of OpenSatNav.

    OpenSatNav is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenSatNav is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with OpenSatNav.  If not, see <http://www.gnu.org/licenses/>.
*/
// Created by plusminus on 21:28:12 - 25.09.2008
package org.andnav.osm.util;

import org.andnav.osm.util.constants.GeoConstants;
import org.andnav.osm.views.util.constants.MathConstants;

/**
 * 
 * @author Nicolas Gramlich
 *
 */
public class GeoPoint implements MathConstants, GeoConstants{
	// ===========================================================
	// Constants
	// ===========================================================

	// ===========================================================
	// Fields
	// ===========================================================
	
	private int mLongitudeE6;
	private int mLatitudeE6;

	// ===========================================================
	// Constructors
	// ===========================================================
	
	public GeoPoint(final int aLatitudeE6, final int aLongitudeE6) {
		this.mLatitudeE6 = aLatitudeE6;
		this.mLongitudeE6 = aLongitudeE6;
	}
	
	public static GeoPoint fromDoubleString(final String s, final char spacer) {
		final int spacerPos = s.indexOf(spacer);
		return new GeoPoint((int) (Double.parseDouble(s.substring(0,
				spacerPos)) * 1E6), (int) (Double.parseDouble(s.substring(
				spacerPos + 1, s.length())) * 1E6));
	}
	
	public static GeoPoint fromIntString(final String s){
		final int commaPos = s.indexOf(',');
		return new GeoPoint(Integer.parseInt(s.substring(0,commaPos)),
				Integer.parseInt(s.substring(commaPos+1,s.length())));
	} 

	// ===========================================================
	// Getter & Setter
	// ===========================================================
	
	public int getLongitudeE6() {
		return this.mLongitudeE6;
	}

	public int getLatitudeE6() {
		return this.mLatitudeE6;
	}
	
	public void setLongitudeE6(final int aLongitudeE6) {
		this.mLongitudeE6 = aLongitudeE6;
	}

	public void setLatitudeE6(final int aLatitudeE6) {
		this.mLatitudeE6 = aLatitudeE6;
	}
	
	public void setCoordsE6(final int aLatitudeE6, final int aLongitudeE6) {
		this.mLatitudeE6 = aLatitudeE6;
		this.mLongitudeE6 = aLongitudeE6;
	}

	// ===========================================================
	// Methods from SuperClass/Interfaces
	// ===========================================================
	
	@Override
	public String toString(){
		return new StringBuilder().append(this.mLatitudeE6).append(",").append(this.mLongitudeE6).toString();
	}

	public String toDoubleString() {
		return new StringBuilder().append(this.mLatitudeE6 / 1E6).append(",").append(this.mLongitudeE6  / 1E6).toString();
	}
	
	@Override
	public boolean equals(Object obj) {
		if(!(obj instanceof GeoPoint))
			return false;
		GeoPoint g = (GeoPoint)obj;
		return g.mLatitudeE6 == this.mLatitudeE6 && g.mLongitudeE6 == this.mLongitudeE6;
	}

	// ===========================================================
	// Methods
	// ===========================================================
	
	/**
	 * @see Source@ http://www.geocities.com/DrChengalva/GPSDistance.html
	 * @param gpA
	 * @param gpB
	 * @return distance in meters
	 */
	public int distanceTo(final GeoPoint other) {		

		final double a1 = DEG2RAD * (this.mLatitudeE6 / 1E6);
		final double a2 = DEG2RAD * (this.mLongitudeE6 / 1E6);
		final double b1 = DEG2RAD * (other.mLatitudeE6 / 1E6);
		final double b2 = DEG2RAD * (other.mLongitudeE6 / 1E6);

		final double cosa1 = Math.cos(a1);
		final double cosb1 = Math.cos(b1);
		
		final double t1 = cosa1*Math.cos(a2)*cosb1*Math.cos(b2);
		
		final double t2 = cosa1*Math.sin(a2)*cosb1*Math.sin(b2);

		final double t3 = Math.sin(a1)*Math.sin(b1);

		final double tt = Math.acos( t1 + t2 + t3 );

		return (int)(RADIUS_EARTH_METERS*tt);
	}

	// ===========================================================
	// Inner and Anonymous Classes
	// ===========================================================
}