var adjust_lon = require('../common/adjust_lon');
|
/*
|
reference
|
"New Equal-Area Map Projections for Noncircular Regions", John P. Snyder,
|
The American Cartographer, Vol 15, No. 4, October 1988, pp. 341-355.
|
*/
|
|
|
/* Initialize the Miller Cylindrical projection
|
-------------------------------------------*/
|
exports.init = function() {
|
//no-op
|
};
|
|
|
/* Miller Cylindrical forward equations--mapping lat,long to x,y
|
------------------------------------------------------------*/
|
exports.forward = function(p) {
|
var lon = p.x;
|
var lat = p.y;
|
/* Forward equations
|
-----------------*/
|
var dlon = adjust_lon(lon - this.long0);
|
var x = this.x0 + this.a * dlon;
|
var y = this.y0 + this.a * Math.log(Math.tan((Math.PI / 4) + (lat / 2.5))) * 1.25;
|
|
p.x = x;
|
p.y = y;
|
return p;
|
};
|
|
/* Miller Cylindrical inverse equations--mapping x,y to lat/long
|
------------------------------------------------------------*/
|
exports.inverse = function(p) {
|
p.x -= this.x0;
|
p.y -= this.y0;
|
|
var lon = adjust_lon(this.long0 + p.x / this.a);
|
var lat = 2.5 * (Math.atan(Math.exp(0.8 * p.y / this.a)) - Math.PI / 4);
|
|
p.x = lon;
|
p.y = lat;
|
return p;
|
};
|
exports.names = ["Miller_Cylindrical", "mill"];
|
