+ end
+
+ # Helper methods for going to/from mercator and lat/lng.
+ class Mercator
+ include Math
+
+ #init me with your bounding box and the size of your image
+ def initialize(min_lat, min_lon, max_lat, max_lon, width, height)
+ xsize = xsheet(max_lon) - xsheet(min_lon)
+ ysize = ysheet(max_lat) - ysheet(min_lat)
+ xscale = xsize / width
+ yscale = ysize / height
+ scale = [xscale, yscale].max