Script to merge a topo map with an overhead map from pynemap

mergeTopo.py

import Image
import math

im = Image.open("minecraft_map_topo.png")
rotatedTopo = im.rotate(-90)

im = Image.open("minecraft_map.png")
rotatedTerrain = im.rotate(-90)

terrainPix = rotatedTerrain.load()
topoPix = rotatedTopo.load()

assert(rotatedTerrain.size == rotatedTopo.size)

def scalePixel(scale, (r, g, b, a)):     
  return (int(r*scale), int(g*scale), int(b*scale), a)
  
def topoValue(x, y):
  r, g, b, a = topoPix[x, y]
  return r - b + 255 - g
    
width, height = rotatedTerrain.size
for x in xrange(1, width):
  for y in xrange(1, height):
    delta = (topoValue(x, y) - topoValue(x-1, y))/512.0
    # then use magical scaling formula (the hard part is highlighting the small height 
    # differences without washing out the large height differences
    scale = (math.atan(delta*15) + 1.5707963267) / 1.5707963267

    terrainPix[x, y] = scalePixel(scale, terrainPix[x, y])

rotatedTerrain.save("minecraft_minimap.png")