pj_robin.js

Robinson projection library - javascript port of PJ_robin.c from PROJ.4 (v4.7.0). Use it to make less-stretchified (but bendy around the edges) global interactive slippy maps :)

Node.js usage

Install using npm.

npm install pj_robin

Frivolous example code:

var Robinson = require('pj_robin'),
    pt = Robinson.project(51.507222, -0.1275);
console.log("London is at x:"+pt.x+" y:"+pt.y);

Browser usage

Use the minified javascript file (which can be rebuilt using the included Makefile).

<script src='pj_robin.min.js'></script>
<script>
    var pt = Robinson.project(51.507222, -0.1275);
    alert("London is at x:"+pt.x+" y:"+pt.y);
</script>

API reference

Robinson.project(lat, lng) -> Point

Project a latitude / longitude (in degrees).

Returns an object with x and y properties.

Aside: I think this conversion uses a unit sphere (TODO confirm this).

Robinson.unproject(x, y) -> LatLng

Unproject an x / y point.

Returns an object with lat and lng properties.

Robinson.remap(pt) -> Point

Re-map a projected point to 0 <= x/y < 1 range.

(useful for operations on square map tiles)