zonedutmpoint.java

openmap java写的开源数字地图程序. 用applet实现,可以像google map 那样放大缩小地图.

//**********************************************************************
//
//<copyright>
//
//BBN Technologies, a Verizon Company
//10 Moulton Street
//Cambridge, MA 02138
//[phone]
//
//Copyright (C) BBNT Solutions LLC. All rights reserved.
//
//</copyright>
//**********************************************************************
//
//$Source:
///cvs/darwars/ambush/aar/src/com/bbn/ambush/mission/MissionHandler.java,v
//$
//$RCSfile: ZonedUTMPoint.java,v $
//$Revision: 1.1.2.2 $
//$Date: 2005/08/11 21:03:10 $
//$Author: dietrick $
//
//**********************************************************************

package com.bbn.openmap.proj.coords;

import com.bbn.openmap.LatLonPoint;
import com.bbn.openmap.proj.Ellipsoid;

/**
 * A ZonedUTMPoint is a UTMPoint that handles a MGRS zone letter
 * instead of N or S.
 * 
 * @author dietrick
 */
public class ZonedUTMPoint extends UTMPoint {

    /**
     * Constructor pass-through.
     */
    public ZonedUTMPoint() {
        super();
    }

    /**
     * @param northing The northing component.
     * @param easting The easting component.
     * @param zone_number The zone of the coordinate.
     * @param zone_letter MGRS zone letter
     */
    public ZonedUTMPoint(float northing, float easting, int zone_number,
            char zone_letter) {
        super(northing,
              easting,
              zone_number,
              MGRSPoint.MGRSZoneToUTMZone(zone_letter));
    }

    /**
     * Constructor pass-through.
     */
    public ZonedUTMPoint(UTMPoint point) {
        super(point);
    }

    /**
     * Constructor pass-through.
     */
    public ZonedUTMPoint(LatLonPoint llpoint) {
        super(llpoint);
    }

    /**
     * Constructor pass-through.
     */
    public ZonedUTMPoint(LatLonPoint llpoint, Ellipsoid ellip) {
        super(llpoint, ellip);
    }

    /**
     * Converts UTM coords to lat/long given an ellipsoid.
     * <p>
     * Equations from USGS Bulletin 1532 <br>
     * East Longitudes are positive, West longitudes are negative.
     * <br>
     * North latitudes are positive, South latitudes are negative.
     * <br>
     * 
     * @param ellip an ellipsoid definition.
     * @param UTMNorthing A float value for the northing to be
     *        converted.
     * @param UTMEasting A float value for the easting to be
     *        converted.
     * @param ZoneNumber An int value specifiying the UTM zone number.
     * @param ZoneLetter A char value specifying the ZoneLetter within
     *        the ZoneNumber, letter being MGRS zone.
     * @param llpoint a LatLonPoint, if you want it to be filled in
     *        with the results. If null, a new LatLonPoint will be
     *        allocated.
     * @return A LatLonPoint class instance containing the lat/long
     *         value, or <code>null</code> if conversion failed. If
     *         you pass in a LatLonPoint, it will be returned as well,
     *         if successful.
     */
    public static LatLonPoint ZonedUTMtoLL(Ellipsoid ellip, float UTMNorthing,
                                           float UTMEasting, int ZoneNumber,
                                           char ZoneLetter, LatLonPoint llpoint) {
        return UTMPoint.UTMtoLL(ellip, UTMNorthing, UTMEasting, ZoneNumber,
                MGRSPoint.MGRSZoneToUTMZone(ZoneLetter), llpoint);
    }

    /**
     * Determines the correct MGRS letter designator for the given
     * latitude returns 'Z' if latitude is outside the MGRS limits of
     * 84N to 80S.
     * 
     * @param lat The float value of the latitude.
     * 
     * @return A char value which is the MGRS zone letter.
     */
    protected char getLetterDesignator(double lat) {

        //This is here as an error flag to show that the Latitude is
        //outside MGRS limits
        char LetterDesignator = 'Z';

        if ((84 >= lat) && (lat >= 72))
            LetterDesignator = 'X';
        else if ((72 > lat) && (lat >= 64))
            LetterDesignator = 'W';
        else if ((64 > lat) && (lat >= 56))
            LetterDesignator = 'V';
        else if ((56 > lat) && (lat >= 48))
            LetterDesignator = 'U';
        else if ((48 > lat) && (lat >= 40))
            LetterDesignator = 'T';
        else if ((40 > lat) && (lat >= 32))
            LetterDesignator = 'S';
        else if ((32 > lat) && (lat >= 24))
            LetterDesignator = 'R';
        else if ((24 > lat) && (lat >= 16))
            LetterDesignator = 'Q';
        else if ((16 > lat) && (lat >= 8))
            LetterDesignator = 'P';
        else if ((8 > lat) && (lat >= 0))
            LetterDesignator = 'N';
        else if ((0 > lat) && (lat >= -8))
            LetterDesignator = 'M';
        else if ((-8 > lat) && (lat >= -16))
            LetterDesignator = 'L';
        else if ((-16 > lat) && (lat >= -24))
            LetterDesignator = 'K';
        else if ((-24 > lat) && (lat >= -32))
            LetterDesignator = 'J';
        else if ((-32 > lat) && (lat >= -40))
            LetterDesignator = 'H';
        else if ((-40 > lat) && (lat >= -48))
            LetterDesignator = 'G';
        else if ((-48 > lat) && (lat >= -56))
            LetterDesignator = 'F';
        else if ((-56 > lat) && (lat >= -64))
            LetterDesignator = 'E';
        else if ((-64 > lat) && (lat >= -72))
            LetterDesignator = 'D';
        else if ((-72 > lat) && (lat >= -80))
            LetterDesignator = 'C';
        return LetterDesignator;
    }

}