duncanbeevers

# Usage
# projection = MapProjection::WinkelTripel.new(w, h)
# projections.project( latitude, longitude)
#   => [ x, y ] # cartesian coordinates
# Where x and y will be between 0, 0 (upper-left) and w, h (lower-right)
#   suitable for compositing images on a bitmap

module Math
  DEG2RAD = PI / 180
  

humanzz

# This is a port of the javascript code found in the following link
#http://groups.google.com/group/Google-Maps-API/browse_thread/thread/a45947d72c27cc73

class Mercator
  #offset is defined at zoom level 21 which means that this Mercator is valid for 21 zoom levels
  OFFSET = 268435456
  RADIUS = OFFSET / Math::PI
  
  def self.lng_to_x(lng, zoom)
    (OFFSET + RADIUS * lng * Math::PI / 180).to_i >> (21 - zoom)