//------------------------------------------------------------------------------
// geotool.js - version 1.0.0
//
//  Copyright (c) 2005 Craftworks Corp. All Right Reserved.
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2.1 of the License, or (at your option) any later version.
//
//  This library 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
//  Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with this library; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//  For details, see the Craftworks web site: http://www.craft-works.co.jp/
//
//  AUTHOR: Isam Nakane <isam@craft-works.co.jp>
//
//  SYNOPSIS:
//      wgs = Geotool.wgs2tky(deg.lat, deg.lng);
//      dms.lat = Geotool.dms2deg(wgs.lat);
//      dms.lng = Geotool.dms2deg(wgs.lng);
//      boolean = Geotool.isJapan(deg.lat, deg.lng);
//
//------------------------------------------------------------------------------


var Geotool = {
    // radian
    RD : Math.PI / 180,

    // --------------- WGS 84 ---------------
    // (Equatorial radius, Ellipticity, Eccentricity)
    A_WGS  : 6378137,
    F_WGS  : 1 / 298.257222101,
    E2_WGS : 0.006694380022900787, // 2 * F_WGS - Math.pow(F_WGS, 2)

    // --------------- Bessel 1841 ---------------
    // (Equatorial radius, Ellipticity, Eccentricity)
    A_TKY  : 6377397.155,
    F_TKY  : 1 / 299.1528128,
    E2_TKY : 0.006674372231802145, // 2 * F_TKY - Math.pow(F_TKY, 2)

    // parallel distance
    DX_T :  148, DX_W : -148,
    DY_T : -507, DY_W : +507, 
    DZ_T : -681, DZ_W : +681, 

    dms2deg : function(dms) {
        dms = dms + "";
        if (dms.match(/^(\d{2,3})(\d{2})(\d{2}\.?\d*)$/)) {
            return (RegExp.$1 / 1 + RegExp.$2 / 60 + RegExp.$3 / 3600);
        } else {
            return false;
        }
    },

    deg2dms : function(deg) {
        var sf = Math.round(deg * 360000);
        var s  = Math.floor(sf / 100) % 60;
        var m  = Math.floor(sf / 6000) % 60;
        var d = Math.floor(sf / 360000);
        sf %= 100;
        if (m  < 10) m  = "0" + m;
        if (s  < 10) s  = "0" + s;
        if (sf < 10) sf = "0" + sf;
        var dms = "" + d + m + s + "." + sf;
        return dms;
    },

    blh2xyz : function(b, l, h, a, e2) {
        b *= this.RD;
        l *= this.RD;
        var sb = Math.sin(b);
        var cb = Math.cos(b);
        var rn = a / Math.sqrt(1 - e2 * Math.pow(sb, 2));
        var x = (rn + h) * cb * Math.cos(l);
        var y = (rn + h) * cb * Math.sin(l);
        var z = (rn * (1 - e2) + h) * sb;
        return [x, y, z];
    },

    xyz2blh : function(x, y, z, a, e2) {
        var bda = Math.sqrt(1 - e2);
        var p = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
        var t = Math.atan2(z, p * bda);
        var st = Math.sin(t);
        var ct = Math.cos(t);
        var b = Math.atan2(z + e2 * a / bda * Math.pow(st, 3), p - e2 * a * Math.pow(ct, 3));
        var l = Math.atan2(y, x);
        var sb = Math.sin(b);
        var rn = a / Math.sqrt(1 - e2 * Math.pow(sb, 2));
        var h = p / Math.cos(b) - rn;
        var blh = new Array(b / this.RD, l / this.RD, h);
        return blh;
    },

    wgs2tky : function(bb, bl) { // lat, lng (degree)
        var xyz = this.blh2xyz(bb, bl, 0, this.A_WGS, this.E2_WGS);
        var blh = this.xyz2blh(xyz[0] + this.DX_T, xyz[1] + this.DY_T, xyz[2] + this.DZ_T, this.A_TKY, this.E2_TKY);
        return { x : blh[1], y : blh[0], lat : blh[0], lng : blh[1] };
    },

    tky2wgs : function(bb, bl) { // lat, lng (degree)
        var xyz = this.blh2xyz(bb, bl, 0, this.A_TKY, this.E2_TKY);
        var blh = this.xyz2blh(xyz[0] + this.DX_W, xyz[1] + this.DY_W, xyz[2] + this.DZ_W, this.A_WGS, this.E2_WGS);
        return { x : blh[1], y : blh[0], lat : blh[0], lng : blh[1] };
    },

    isJapan : function(lat, lng) { // WGS
        if (   lat >  30 && lat <  50
            && lng > 115 && lng < 152 ) {
            return true;
        } else {
            return false;
        }
    }

};