Draw world map on canvas
##Inroduction
Spent quite some time searching on web on converting latitude/longitude to pixel. Pretty common question I thought. Amazingly, no simple answer. Everybody wanted to write either a academic paper, or a gmap tutorial.
WTF, I just wanted to draw a small world map and plot some stuff on top! What projection? Well, the one that commonly used by 3rd party ip to lat/lon translation.
Until somebody mentioned, for small size map, lat/lon are quite linear...
So, here is the magic formula:
var x = ((lng / 360) + 0.5) * width;
var y = (1 - ((lat / 180) + 0.5)) * height;
Then get lands shapfile from Natural Earth. Extract out lat/lon by using shpdump. We got a map.
##Screenshot
