/*******************************************************************************
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NAME LAMBERT CONFORMAL CONIC
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PURPOSE: Transforms input longitude and latitude to Easting and
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Northing for the Lambert Conformal Conic 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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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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*******************************************************************************/
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//<2104> +proj=lcc +lat_1=10.16666666666667 +lat_0=10.16666666666667 +lon_0=-71.60561777777777 +k_0=1 +x0=-17044 +x0=-23139.97 +ellps=intl +units=m +no_defs no_defs
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// Initialize the Lambert Conformal conic projection
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// -----------------------------------------------------------------
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//Proj4js.Proj.lcc = Class.create();
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Proj4js.Proj.lcc = {
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init : function() {
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// array of: r_maj,r_min,lat1,lat2,c_lon,c_lat,false_east,false_north
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//double c_lat; /* center latitude */
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//double c_lon; /* center longitude */
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//double lat1; /* first standard parallel */
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//double lat2; /* second standard parallel */
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//double r_maj; /* major axis */
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//double r_min; /* minor axis */
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//double false_east; /* x offset in meters */
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//double false_north; /* y offset in meters */
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if (!this.lat2){this.lat2=this.lat0;}//if lat2 is not defined
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if (!this.k0) this.k0 = 1.0;
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// Standard Parallels cannot be equal and on opposite sides of the equator
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if (Math.abs(this.lat1+this.lat2) < Proj4js.common.EPSLN) {
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Proj4js.reportError("lcc:init: Equal Latitudes");
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return;
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}
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var temp = this.b / this.a;
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this.e = Math.sqrt(1.0 - temp*temp);
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var sin1 = Math.sin(this.lat1);
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var cos1 = Math.cos(this.lat1);
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var ms1 = Proj4js.common.msfnz(this.e, sin1, cos1);
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var ts1 = Proj4js.common.tsfnz(this.e, this.lat1, sin1);
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var sin2 = Math.sin(this.lat2);
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var cos2 = Math.cos(this.lat2);
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var ms2 = Proj4js.common.msfnz(this.e, sin2, cos2);
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var ts2 = Proj4js.common.tsfnz(this.e, this.lat2, sin2);
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var ts0 = Proj4js.common.tsfnz(this.e, this.lat0, Math.sin(this.lat0));
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if (Math.abs(this.lat1 - this.lat2) > Proj4js.common.EPSLN) {
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this.ns = Math.log(ms1/ms2)/Math.log(ts1/ts2);
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} else {
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this.ns = sin1;
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}
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this.f0 = ms1 / (this.ns * Math.pow(ts1, this.ns));
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this.rh = this.a * this.f0 * Math.pow(ts0, this.ns);
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if (!this.title) this.title = "Lambert Conformal Conic";
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},
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// Lambert Conformal conic forward equations--mapping lat,long to x,y
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// -----------------------------------------------------------------
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forward : function(p) {
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var lon = p.x;
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var lat = p.y;
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// convert to radians
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if ( lat <= 90.0 && lat >= -90.0 && lon <= 180.0 && lon >= -180.0) {
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//lon = lon * Proj4js.common.D2R;
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//lat = lat * Proj4js.common.D2R;
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} else {
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Proj4js.reportError("lcc:forward: llInputOutOfRange: "+ lon +" : " + lat);
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return null;
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}
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var con = Math.abs( Math.abs(lat) - Proj4js.common.HALF_PI);
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var ts, rh1;
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if (con > Proj4js.common.EPSLN) {
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ts = Proj4js.common.tsfnz(this.e, lat, Math.sin(lat) );
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rh1 = this.a * this.f0 * Math.pow(ts, this.ns);
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} else {
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con = lat * this.ns;
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if (con <= 0) {
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Proj4js.reportError("lcc:forward: No Projection");
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return null;
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}
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rh1 = 0;
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}
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var theta = this.ns * Proj4js.common.adjust_lon(lon - this.long0);
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p.x = this.k0 * (rh1 * Math.sin(theta)) + this.x0;
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p.y = this.k0 * (this.rh - rh1 * Math.cos(theta)) + this.y0;
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return p;
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},
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// Lambert Conformal Conic inverse equations--mapping x,y to lat/long
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// -----------------------------------------------------------------
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inverse : function(p) {
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var rh1, con, ts;
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var lat, lon;
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var x = (p.x - this.x0)/this.k0;
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var y = (this.rh - (p.y - this.y0)/this.k0);
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if (this.ns > 0) {
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rh1 = Math.sqrt (x * x + y * y);
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con = 1.0;
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} else {
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rh1 = -Math.sqrt (x * x + y * y);
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con = -1.0;
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}
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var theta = 0.0;
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if (rh1 != 0) {
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theta = Math.atan2((con * x),(con * y));
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}
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if ((rh1 != 0) || (this.ns > 0.0)) {
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con = 1.0/this.ns;
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ts = Math.pow((rh1/(this.a * this.f0)), con);
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lat = Proj4js.common.phi2z(this.e, ts);
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if (lat == -9999) return null;
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} else {
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lat = -Proj4js.common.HALF_PI;
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}
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lon = Proj4js.common.adjust_lon(theta/this.ns + this.long0);
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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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