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257 lines
9.1 KiB
JavaScript
257 lines
9.1 KiB
JavaScript
/*******************************************************************************
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NAME OBLIQUE MERCATOR (HOTINE)
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PURPOSE: Transforms input longitude and latitude to Easting and
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Northing for the Oblique Mercator projection. The
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longitude and latitude must be in radians. The Easting
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and Northing values will be returned in meters.
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PROGRAMMER DATE
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---------- ----
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T. Mittan Mar, 1993
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ALGORITHM REFERENCES
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1. Snyder, John P., "Map Projections--A Working Manual", U.S. Geological
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Survey Professional Paper 1395 (Supersedes USGS Bulletin 1532), United
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State Government Printing Office, Washington D.C., 1987.
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2. Snyder, John P. and Voxland, Philip M., "An Album of Map Projections",
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U.S. Geological Survey Professional Paper 1453 , United State Government
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Printing Office, Washington D.C., 1989.
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*******************************************************************************/
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Proj4js.Proj.omerc = {
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/* Initialize the Oblique Mercator projection
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------------------------------------------*/
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init: function() {
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if (!this.mode) this.mode=0;
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if (!this.lon1) {this.lon1=0;this.mode=1;}
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if (!this.lon2) this.lon2=0;
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if (!this.lat2) this.lat2=0;
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/* Place parameters in static storage for common use
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-------------------------------------------------*/
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var temp = this.b/ this.a;
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var es = 1.0 - Math.pow(temp,2);
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var e = Math.sqrt(es);
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this.sin_p20=Math.sin(this.lat0);
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this.cos_p20=Math.cos(this.lat0);
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this.con = 1.0 - this.es * this.sin_p20 * this.sin_p20;
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this.com = Math.sqrt(1.0 - es);
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this.bl = Math.sqrt(1.0 + this.es * Math.pow(this.cos_p20,4.0)/(1.0 - es));
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this.al = this.a * this.bl * this.k0 * this.com / this.con;
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if (Math.abs(this.lat0) < Proj4js.common.EPSLN) {
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this.ts = 1.0;
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this.d = 1.0;
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this.el = 1.0;
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} else {
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this.ts = Proj4js.common.tsfnz(this.e,this.lat0,this.sin_p20);
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this.con = Math.sqrt(this.con);
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this.d = this.bl * this.com / (this.cos_p20 * this.con);
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if ((this.d * this.d - 1.0) > 0.0) {
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if (this.lat0 >= 0.0) {
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this.f = this.d + Math.sqrt(this.d * this.d - 1.0);
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} else {
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this.f = this.d - Math.sqrt(this.d * this.d - 1.0);
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}
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} else {
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this.f = this.d;
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}
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this.el = this.f * Math.pow(this.ts,this.bl);
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}
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//this.longc=52.60353916666667;
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if (this.mode != 0) {
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this.g = .5 * (this.f - 1.0/this.f);
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this.gama = Proj4js.common.asinz(Math.sin(this.alpha) / this.d);
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this.longc= this.longc - Proj4js.common.asinz(this.g * Math.tan(this.gama))/this.bl;
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/* Report parameters common to format B
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-------------------------------------*/
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//genrpt(azimuth * R2D,"Azimuth of Central Line: ");
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//cenlon(lon_origin);
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// cenlat(lat_origin);
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this.con = Math.abs(this.lat0);
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if ((this.con > Proj4js.common.EPSLN) && (Math.abs(this.con - Proj4js.common.HALF_PI) > Proj4js.common.EPSLN)) {
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this.singam=Math.sin(this.gama);
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this.cosgam=Math.cos(this.gama);
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this.sinaz=Math.sin(this.alpha);
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this.cosaz=Math.cos(this.alpha);
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if (this.lat0>= 0) {
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this.u = (this.al / this.bl) * Math.atan(Math.sqrt(this.d*this.d - 1.0)/this.cosaz);
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} else {
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this.u = -(this.al / this.bl) *Math.atan(Math.sqrt(this.d*this.d - 1.0)/this.cosaz);
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}
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} else {
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Proj4js.reportError("omerc:Init:DataError");
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}
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} else {
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this.sinphi =Math. sin(this.at1);
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this.ts1 = Proj4js.common.tsfnz(this.e,this.lat1,this.sinphi);
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this.sinphi = Math.sin(this.lat2);
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this.ts2 = Proj4js.common.tsfnz(this.e,this.lat2,this.sinphi);
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this.h = Math.pow(this.ts1,this.bl);
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this.l = Math.pow(this.ts2,this.bl);
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this.f = this.el/this.h;
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this.g = .5 * (this.f - 1.0/this.f);
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this.j = (this.el * this.el - this.l * this.h)/(this.el * this.el + this.l * this.h);
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this.p = (this.l - this.h) / (this.l + this.h);
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this.dlon = this.lon1 - this.lon2;
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if (this.dlon < -Proj4js.common.PI) this.lon2 = this.lon2 - 2.0 * Proj4js.common.PI;
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if (this.dlon > Proj4js.common.PI) this.lon2 = this.lon2 + 2.0 * Proj4js.common.PI;
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this.dlon = this.lon1 - this.lon2;
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this.longc = .5 * (this.lon1 + this.lon2) -Math.atan(this.j * Math.tan(.5 * this.bl * this.dlon)/this.p)/this.bl;
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this.dlon = Proj4js.common.adjust_lon(this.lon1 - this.longc);
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this.gama = Math.atan(Math.sin(this.bl * this.dlon)/this.g);
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this.alpha = Proj4js.common.asinz(this.d * Math.sin(this.gama));
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/* Report parameters common to format A
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-------------------------------------*/
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if (Math.abs(this.lat1 - this.lat2) <= Proj4js.common.EPSLN) {
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Proj4js.reportError("omercInitDataError");
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//return(202);
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} else {
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this.con = Math.abs(this.lat1);
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}
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if ((this.con <= Proj4js.common.EPSLN) || (Math.abs(this.con - Proj4js.common.HALF_PI) <= Proj4js.common.EPSLN)) {
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Proj4js.reportError("omercInitDataError");
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//return(202);
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} else {
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if (Math.abs(Math.abs(this.lat0) - Proj4js.common.HALF_PI) <= Proj4js.common.EPSLN) {
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Proj4js.reportError("omercInitDataError");
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//return(202);
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}
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}
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this.singam=Math.sin(this.gam);
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this.cosgam=Math.cos(this.gam);
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this.sinaz=Math.sin(this.alpha);
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this.cosaz=Math.cos(this.alpha);
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if (this.lat0 >= 0) {
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this.u = (this.al/this.bl) * Math.atan(Math.sqrt(this.d * this.d - 1.0)/this.cosaz);
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} else {
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this.u = -(this.al/this.bl) * Math.atan(Math.sqrt(this.d * this.d - 1.0)/this.cosaz);
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}
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}
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},
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/* Oblique Mercator forward equations--mapping lat,long to x,y
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----------------------------------------------------------*/
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forward: function(p) {
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var theta; /* angle */
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var sin_phi, cos_phi;/* sin and cos value */
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var b; /* temporary values */
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var c, t, tq; /* temporary values */
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var con, n, ml; /* cone constant, small m */
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var q,us,vl;
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var ul,vs;
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var s;
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var dlon;
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var ts1;
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var lon=p.x;
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var lat=p.y;
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/* Forward equations
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-----------------*/
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sin_phi = Math.sin(lat);
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dlon = Proj4js.common.adjust_lon(lon - this.longc);
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vl = Math.sin(this.bl * dlon);
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if (Math.abs(Math.abs(lat) - Proj4js.common.HALF_PI) > Proj4js.common.EPSLN) {
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ts1 = Proj4js.common.tsfnz(this.e,lat,sin_phi);
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q = this.el / (Math.pow(ts1,this.bl));
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s = .5 * (q - 1.0 / q);
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t = .5 * (q + 1.0/ q);
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ul = (s * this.singam - vl * this.cosgam) / t;
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con = Math.cos(this.bl * dlon);
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if (Math.abs(con) < .0000001) {
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us = this.al * this.bl * dlon;
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} else {
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us = this.al * Math.atan((s * this.cosgam + vl * this.singam) / con)/this.bl;
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if (con < 0) us = us + Proj4js.common.PI * this.al / this.bl;
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}
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} else {
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if (lat >= 0) {
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ul = this.singam;
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} else {
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ul = -this.singam;
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}
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us = this.al * lat / this.bl;
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}
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if (Math.abs(Math.abs(ul) - 1.0) <= Proj4js.common.EPSLN) {
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//alert("Point projects into infinity","omer-for");
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Proj4js.reportError("omercFwdInfinity");
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//return(205);
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}
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vs = .5 * this.al * Math.log((1.0 - ul)/(1.0 + ul)) / this.bl;
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us = us - this.u;
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var x = this.x0 + vs * this.cosaz + us * this.sinaz;
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var y = this.y0 + us * this.cosaz - vs * this.sinaz;
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p.x=x;
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p.y=y;
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return p;
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},
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inverse: function(p) {
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var delta_lon; /* Delta longitude (Given longitude - center */
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var theta; /* angle */
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var delta_theta; /* adjusted longitude */
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var sin_phi, cos_phi;/* sin and cos value */
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var b; /* temporary values */
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var c, t, tq; /* temporary values */
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var con, n, ml; /* cone constant, small m */
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var vs,us,q,s,ts1;
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var vl,ul,bs;
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var lon, lat;
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var flag;
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/* Inverse equations
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-----------------*/
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p.x -= this.x0;
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p.y -= this.y0;
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flag = 0;
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vs = p.x * this.cosaz - p.y * this.sinaz;
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us = p.y * this.cosaz + p.x * this.sinaz;
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us = us + this.u;
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q = Math.exp(-this.bl * vs / this.al);
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s = .5 * (q - 1.0/q);
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t = .5 * (q + 1.0/q);
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vl = Math.sin(this.bl * us / this.al);
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ul = (vl * this.cosgam + s * this.singam)/t;
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if (Math.abs(Math.abs(ul) - 1.0) <= Proj4js.common.EPSLN)
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{
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lon = this.longc;
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if (ul >= 0.0) {
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lat = Proj4js.common.HALF_PI;
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} else {
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lat = -Proj4js.common.HALF_PI;
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}
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} else {
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con = 1.0 / this.bl;
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ts1 =Math.pow((this.el / Math.sqrt((1.0 + ul) / (1.0 - ul))),con);
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lat = Proj4js.common.phi2z(this.e,ts1);
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//if (flag != 0)
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//return(flag);
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//~ con = Math.cos(this.bl * us /al);
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theta = this.longc - Math.atan2((s * this.cosgam - vl * this.singam) , con)/this.bl;
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lon = Proj4js.common.adjust_lon(theta);
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}
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p.x=lon;
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p.y=lat;
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return p;
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}
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};
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