First commit

node_modules/proj4/lib/projections/gstmerc.js

@@ -0,0 +1,63 @@
+import latiso from '../common/latiso';
+import sinh from '../common/sinh';
+import cosh from '../common/cosh';
+import invlatiso from '../common/invlatiso';
+
+export function init() {
+
+  // array of:  a, b, lon0, lat0, k0, x0, y0
+  var temp = this.b / this.a;
+  this.e = Math.sqrt(1 - temp * temp);
+  this.lc = this.long0;
+  this.rs = Math.sqrt(1 + this.e * this.e * Math.pow(Math.cos(this.lat0), 4) / (1 - this.e * this.e));
+  var sinz = Math.sin(this.lat0);
+  var pc = Math.asin(sinz / this.rs);
+  var sinzpc = Math.sin(pc);
+  this.cp = latiso(0, pc, sinzpc) - this.rs * latiso(this.e, this.lat0, sinz);
+  this.n2 = this.k0 * this.a * Math.sqrt(1 - this.e * this.e) / (1 - this.e * this.e * sinz * sinz);
+  this.xs = this.x0;
+  this.ys = this.y0 - this.n2 * pc;
+
+  if (!this.title) {
+    this.title = "Gauss Schreiber transverse mercator";
+  }
+}
+
+// forward equations--mapping lat,long to x,y
+// -----------------------------------------------------------------
+export function forward(p) {
+
+  var lon = p.x;
+  var lat = p.y;
+
+  var L = this.rs * (lon - this.lc);
+  var Ls = this.cp + (this.rs * latiso(this.e, lat, Math.sin(lat)));
+  var lat1 = Math.asin(Math.sin(L) / cosh(Ls));
+  var Ls1 = latiso(0, lat1, Math.sin(lat1));
+  p.x = this.xs + (this.n2 * Ls1);
+  p.y = this.ys + (this.n2 * Math.atan(sinh(Ls) / Math.cos(L)));
+  return p;
+}
+
+// inverse equations--mapping x,y to lat/long
+// -----------------------------------------------------------------
+export function inverse(p) {
+
+  var x = p.x;
+  var y = p.y;
+
+  var L = Math.atan(sinh((x - this.xs) / this.n2) / Math.cos((y - this.ys) / this.n2));
+  var lat1 = Math.asin(Math.sin((y - this.ys) / this.n2) / cosh((x - this.xs) / this.n2));
+  var LC = latiso(0, lat1, Math.sin(lat1));
+  p.x = this.lc + L / this.rs;
+  p.y = invlatiso(this.e, (LC - this.cp) / this.rs);
+  return p;
+}
+
+export var names = ["gstmerg", "gstmerc"];
+export default {
+  init: init,
+  forward: forward,
+  inverse: inverse,
+  names: names
+};