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node_modules/proj4/lib/projections/merc.js

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+import msfnz from '../common/msfnz';
+
+import adjust_lon from '../common/adjust_lon';
+import tsfnz from '../common/tsfnz';
+import phi2z from '../common/phi2z';
+import {FORTPI, R2D, EPSLN, HALF_PI} from '../constants/values';
+export function init() {
+  var con = this.b / this.a;
+  this.es = 1 - con * con;
+  if(!('x0' in this)){
+    this.x0 = 0;
+  }
+  if(!('y0' in this)){
+    this.y0 = 0;
+  }
+  this.e = Math.sqrt(this.es);
+  if (this.lat_ts) {
+    if (this.sphere) {
+      this.k0 = Math.cos(this.lat_ts);
+    }
+    else {
+      this.k0 = msfnz(this.e, Math.sin(this.lat_ts), Math.cos(this.lat_ts));
+    }
+  }
+  else {
+    if (!this.k0) {
+      if (this.k) {
+        this.k0 = this.k;
+      }
+      else {
+        this.k0 = 1;
+      }
+    }
+  }
+}
+
+/* Mercator forward equations--mapping lat,long to x,y
+  --------------------------------------------------*/
+
+export function forward(p) {
+  var lon = p.x;
+  var lat = p.y;
+  // convert to radians
+  if (lat * R2D > 90 && lat * R2D < -90 && lon * R2D > 180 && lon * R2D < -180) {
+    return null;
+  }
+
+  var x, y;
+  if (Math.abs(Math.abs(lat) - HALF_PI) <= EPSLN) {
+    return null;
+  }
+  else {
+    if (this.sphere) {
+      x = this.x0 + this.a * this.k0 * adjust_lon(lon - this.long0);
+      y = this.y0 + this.a * this.k0 * Math.log(Math.tan(FORTPI + 0.5 * lat));
+    }
+    else {
+      var sinphi = Math.sin(lat);
+      var ts = tsfnz(this.e, lat, sinphi);
+      x = this.x0 + this.a * this.k0 * adjust_lon(lon - this.long0);
+      y = this.y0 - this.a * this.k0 * Math.log(ts);
+    }
+    p.x = x;
+    p.y = y;
+    return p;
+  }
+}
+
+/* Mercator inverse equations--mapping x,y to lat/long
+  --------------------------------------------------*/
+export function inverse(p) {
+
+  var x = p.x - this.x0;
+  var y = p.y - this.y0;
+  var lon, lat;
+
+  if (this.sphere) {
+    lat = HALF_PI - 2 * Math.atan(Math.exp(-y / (this.a * this.k0)));
+  }
+  else {
+    var ts = Math.exp(-y / (this.a * this.k0));
+    lat = phi2z(this.e, ts);
+    if (lat === -9999) {
+      return null;
+    }
+  }
+  lon = adjust_lon(this.long0 + x / (this.a * this.k0));
+
+  p.x = lon;
+  p.y = lat;
+  return p;
+}
+
+export var names = ["Mercator", "Popular Visualisation Pseudo Mercator", "Mercator_1SP", "Mercator_Auxiliary_Sphere", "merc"];
+export default {
+  init: init,
+  forward: forward,
+  inverse: inverse,
+  names: names
+};