UTMProjection.java

/*
    GNU General Public License
    CacheWolf is a software for PocketPC, Win and Linux that
    enables paperless caching.
    It supports the sites geocaching.com and opencaching.de

    Copyright (C) 2006  CacheWolf development team
	See http://www.cachewolf.de/ for more information.
    This program 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; version 2 of the License.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
package CacheWolf.navi;

import CacheWolf.database.CWPoint;
import ewe.sys.Convert;

public class UTMProjection extends Projection {
    Ellipsoid ellip;

    public UTMProjection(Ellipsoid ellip) {
	this.ellip = ellip;
	zoneSeperately = true;
	// set to something else than 0 causes ProjectedPoint not to set epsgCode. 
	epsgCode = -1;
    }

    //Overrides: project(...) in Projection
    public ProjectedPoint project(CWPoint wgs84, ProjectedPoint pp) {
	// we start with stripe 0, but officially this is stripe 1
	int stripe = (int) Math.floor((wgs84.lonDec - 180) / 6);
	if (stripe < 0)
	    stripe += 60;
	GkProjection.project(wgs84, ellip, 6, (stripe >= 30 ? stripe - 30 : stripe + 30), 3, 0.9996, pp);
	pp.zone = stripe + (int) (Math.floor((wgs84.latDec) / 8) + 13) * 200;
	return pp;
    }

    //Overrides: project(...) in Projection
    public ProjectedPoint project(CWPoint ll, ProjectedPoint pp, int epsg) {
	if (epsg == TransformCoordinates.LOCALSYSTEM_UTM_WGS84)
	    return project(ll, pp);
	throw new UnsupportedOperationException("UTMProjection: project by epsg-code not supported");
    }

    //Overrides: unproject(...) in Projection
    public CWPoint unproject(ProjectedPoint pp) {
	int stripe = pp.zone - (int) Math.floor(pp.zone / 200) * 200;
	int stripelon = stripe * 6 - 177;
	return GkProjection.unproject(pp, stripelon, ellip, 0.9996);
    }

    //Overrides: getNorthing(...) in Projection
    public double getNorthing(ProjectedPoint pp) {
	return (pp.rawNorthing >= 0 ? pp.rawNorthing : pp.rawNorthing + 10000000);
    }

    //Overrides: getEasting(...) in Projection
    public double getEasting(ProjectedPoint pp) {
	return pp.rawEasting + 500000;
    }

    //Overrides: set(...) in Projection
    public ProjectedPoint set(double northing, double easting, String zone, ProjectedPoint pp) {
	if (zone.length() < 1)
	    throw new IllegalArgumentException("UTMProjection.set: zone must be set");
	if (zone.length() > 3)
	    throw new IllegalArgumentException("UTMProjection.set: zone must not have more than 3 letters");
	char lastletter = zone.charAt(zone.length() - 1);
	int zoneletter = -1;
	if ((lastletter > 'a') && (lastletter < 'z'))
	    zoneletter = lastletter - 'a';
	if ((lastletter > 'A') && (lastletter < 'Z'))
	    zoneletter = lastletter - 'A';
	if (zoneletter > 'i' - 'a')
	    zoneletter--;
	if (zoneletter > 'o' - 'a')
	    zoneletter--;
	int zonenumer = -1;
	if (zoneletter == -1) {
	    zoneletter = 'n' - 'a'; // default to northern hemisphere
	    zonenumer = Convert.parseInt(zone);
	} else {
	    zonenumer = Convert.parseInt(zone.substring(0, zone.length() - 1));
	}
	if (zonenumer == -1)
	    throw new IllegalArgumentException("UTMProjection.set: could not parse zone number");
	return set(northing, easting, zonenumer, zoneletter, pp);
    }

    //Overrides: getZone(...) in Projection
    public String getZone(ProjectedPoint pp) {
	int zoneletter = (int) Math.floor(pp.zone / 200);
	return Convert.formatInt(pp.zone - zoneletter * 200 + 1) + getZoneLetter(zoneletter);
    }

    private char getZoneLetter(int number) {
	if (((char) (number)) > 'i' - 'a')
	    number++; // skip I
	if (((char) (number)) > 'o' - 'a')
	    number++; // skip O
	char ret = (char) (number + (int) 'A' - 1);
	return ret;
    }

    /**
     * 
     * @param northing
     * @param easting
     * @param zone
     * @param zoneletternumber
     * @param pp
     * @return
     */
    public ProjectedPoint set(double northing, double easting, int zone, int zoneletternumber, ProjectedPoint pp) {
	pp.rawEasting = easting - 500000;
	if (zoneletternumber < 'n' - 'a' -1) // 'n' is the first band in northern hemisphere,  -1: skip the letter i
	    pp.rawNorthing = northing - 10000000;
	else
	    pp.rawNorthing = northing;
	pp.zone = zone - 1 + zoneletternumber * 200; // internally zone number starts with 0
	return pp;
    }

}