module HSlippyMap ( Tile, tileFromLatLong, tileFromXY ) where type Lat = Float type Long = Float type X = Integer type Y = Integer type ZLevel = Integer data Tile = Tile { lat :: Lat, long :: Long, x :: X, y :: Y, z :: ZLevel } instance Show Tile where show (Tile lat long x y z) = "http://tile.openstreetmap.org/" ++ show z ++ "/" ++ show x ++ "/" ++ show y ++ ".png" tileFromLatLong :: Lat -> Long -> ZLevel -> Tile tileFromLatLong lat lon z = Tile lat lon x y z where x = long2tilex lon z y = lat2tiley lat z tileFromXY :: X -> Y -> ZLevel -> Tile tileFromXY x y z = Tile lat lon x y z where lat = tilex2long x z lon = tiley2lat y z long2tilex lon z = floor((lon + 180) / 360 * (2** fromInteger(z)::Long)) lat2tiley lat z = floor((1.0 - log( tan(lat * pi/180.0) + 1.0 / cos(lat * pi/180.0)) / pi) / 2.0 * (2 ** fromInteger(z)::Long)) tilex2long x z = (fromInteger(x)::Long) / (2.0 ** fromInteger(z)::Long) * 360.0 - 180 tiley2lat y z = 180.0 / pi * atan(0.5 * (exp(n) - exp(-n))) where n = pi - 2.0 * pi * (fromInteger(y)::Long) / (2.0 ** fromInteger(z)::Long)