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 adjust_lon = require('../common/adjust_lon');
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var adjust_lat = require('../common/adjust_lat');
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var mlfn = require('../common/mlfn');
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var EPSLN = 1.0e-10;
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var gN = require('../common/gN');
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var MAX_ITER = 20;
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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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this.temp = this.b / this.a;
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this.es = 1 - Math.pow(this.temp, 2); // devait etre dans tmerc.js mais n y est pas donc je commente sinon retour de valeurs nulles
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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.ml0 = this.a * mlfn(this.e0, this.e1, this.e2, this.e3, this.lat0); //si que des zeros le calcul ne se fait pas
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};
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/* Polyconic 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 x, y, el;
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var dlon = adjust_lon(lon - this.long0);
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el = dlon * Math.sin(lat);
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if (this.sphere) {
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if (Math.abs(lat) <= EPSLN) {
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x = this.a * dlon;
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y = -1 * this.a * this.lat0;
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}
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else {
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x = this.a * Math.sin(el) / Math.tan(lat);
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y = this.a * (adjust_lat(lat - this.lat0) + (1 - Math.cos(el)) / Math.tan(lat));
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}
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}
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else {
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if (Math.abs(lat) <= EPSLN) {
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x = this.a * dlon;
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y = -1 * this.ml0;
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}
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else {
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var nl = gN(this.a, this.e, Math.sin(lat)) / Math.tan(lat);
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x = nl * Math.sin(el);
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y = this.a * mlfn(this.e0, this.e1, this.e2, this.e3, lat) - this.ml0 + nl * (1 - Math.cos(el));
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}
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}
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p.x = x + this.x0;
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p.y = y + this.y0;
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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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var lon, lat, x, y, i;
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var al, bl;
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var phi, dphi;
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x = p.x - this.x0;
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y = p.y - this.y0;
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if (this.sphere) {
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if (Math.abs(y + this.a * this.lat0) <= EPSLN) {
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lon = adjust_lon(x / this.a + this.long0);
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lat = 0;
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}
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else {
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al = this.lat0 + y / this.a;
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bl = x * x / this.a / this.a + al * al;
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phi = al;
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var tanphi;
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for (i = MAX_ITER; i; --i) {
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tanphi = Math.tan(phi);
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dphi = -1 * (al * (phi * tanphi + 1) - phi - 0.5 * (phi * phi + bl) * tanphi) / ((phi - al) / tanphi - 1);
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phi += dphi;
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if (Math.abs(dphi) <= EPSLN) {
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lat = phi;
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break;
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}
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}
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lon = adjust_lon(this.long0 + (Math.asin(x * Math.tan(phi) / this.a)) / Math.sin(lat));
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}
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}
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else {
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if (Math.abs(y + this.ml0) <= EPSLN) {
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lat = 0;
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lon = adjust_lon(this.long0 + x / this.a);
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}
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else {
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al = (this.ml0 + y) / this.a;
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bl = x * x / this.a / this.a + al * al;
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phi = al;
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var cl, mln, mlnp, ma;
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var con;
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for (i = MAX_ITER; i; --i) {
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con = this.e * Math.sin(phi);
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cl = Math.sqrt(1 - con * con) * Math.tan(phi);
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mln = this.a * mlfn(this.e0, this.e1, this.e2, this.e3, phi);
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mlnp = this.e0 - 2 * this.e1 * Math.cos(2 * phi) + 4 * this.e2 * Math.cos(4 * phi) - 6 * this.e3 * Math.cos(6 * phi);
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ma = mln / this.a;
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dphi = (al * (cl * ma + 1) - ma - 0.5 * cl * (ma * ma + bl)) / (this.es * Math.sin(2 * phi) * (ma * ma + bl - 2 * al * ma) / (4 * cl) + (al - ma) * (cl * mlnp - 2 / Math.sin(2 * phi)) - mlnp);
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phi -= dphi;
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if (Math.abs(dphi) <= EPSLN) {
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lat = phi;
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break;
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}
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}
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//lat=phi4z(this.e,this.e0,this.e1,this.e2,this.e3,al,bl,0,0);
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cl = Math.sqrt(1 - this.es * Math.pow(Math.sin(lat), 2)) * Math.tan(lat);
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lon = adjust_lon(this.long0 + Math.asin(x * cl / this.a) / Math.sin(lat));
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}
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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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exports.names = ["Polyconic", "poly"];
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