var e0fn = require('../common/e0fn');
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var e1fn = require('../common/e1fn');
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var e2fn = require('../common/e2fn');
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var e3fn = require('../common/e3fn');
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var msfnz = require('../common/msfnz');
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var mlfn = require('../common/mlfn');
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var adjust_lon = require('../common/adjust_lon');
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var adjust_lat = require('../common/adjust_lat');
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var imlfn = require('../common/imlfn');
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var EPSLN = 1.0e-10;
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exports.init = function() {
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/* Place parameters in static storage for common use
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-------------------------------------------------*/
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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) < EPSLN) {
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return;
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}
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this.lat2 = this.lat2 || this.lat1;
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this.temp = this.b / this.a;
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this.es = 1 - Math.pow(this.temp, 2);
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this.e = Math.sqrt(this.es);
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this.e0 = e0fn(this.es);
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this.e1 = e1fn(this.es);
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this.e2 = e2fn(this.es);
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this.e3 = e3fn(this.es);
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this.sinphi = Math.sin(this.lat1);
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this.cosphi = Math.cos(this.lat1);
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this.ms1 = msfnz(this.e, this.sinphi, this.cosphi);
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this.ml1 = mlfn(this.e0, this.e1, this.e2, this.e3, this.lat1);
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if (Math.abs(this.lat1 - this.lat2) < EPSLN) {
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this.ns = this.sinphi;
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}
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else {
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this.sinphi = Math.sin(this.lat2);
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this.cosphi = Math.cos(this.lat2);
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this.ms2 = msfnz(this.e, this.sinphi, this.cosphi);
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this.ml2 = mlfn(this.e0, this.e1, this.e2, this.e3, this.lat2);
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this.ns = (this.ms1 - this.ms2) / (this.ml2 - this.ml1);
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}
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this.g = this.ml1 + this.ms1 / this.ns;
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this.ml0 = mlfn(this.e0, this.e1, this.e2, this.e3, this.lat0);
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this.rh = this.a * (this.g - this.ml0);
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};
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/* Equidistant Conic forward equations--mapping lat,long to x,y
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-----------------------------------------------------------*/
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exports.forward = function(p) {
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var lon = p.x;
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var lat = p.y;
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var rh1;
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/* Forward equations
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-----------------*/
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if (this.sphere) {
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rh1 = this.a * (this.g - lat);
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}
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else {
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var ml = mlfn(this.e0, this.e1, this.e2, this.e3, lat);
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rh1 = this.a * (this.g - ml);
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}
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var theta = this.ns * adjust_lon(lon - this.long0);
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var x = this.x0 + rh1 * Math.sin(theta);
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var y = this.y0 + this.rh - rh1 * Math.cos(theta);
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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 equations
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-----------------*/
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exports.inverse = function(p) {
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p.x -= this.x0;
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p.y = this.rh - p.y + this.y0;
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var con, rh1, lat, lon;
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if (this.ns >= 0) {
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rh1 = Math.sqrt(p.x * p.x + p.y * p.y);
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con = 1;
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}
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else {
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rh1 = -Math.sqrt(p.x * p.x + p.y * p.y);
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con = -1;
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}
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var theta = 0;
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if (rh1 !== 0) {
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theta = Math.atan2(con * p.x, con * p.y);
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}
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if (this.sphere) {
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lon = adjust_lon(this.long0 + theta / this.ns);
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lat = adjust_lat(this.g - rh1 / this.a);
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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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else {
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var ml = this.g - rh1 / this.a;
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lat = imlfn(ml, this.e0, this.e1, this.e2, this.e3);
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lon = adjust_lon(this.long0 + theta / this.ns);
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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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exports.names = ["Equidistant_Conic", "eqdc"];
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