code: def mapzen_elevation_rgb(arr):
      
      arr = np.clip(arr + 32768.0, 0.0, 65535.0)
      r = arr / 256
      g = arr % 256
      b = (arr * 256) % 256
      return np.stack([r, g, b]).astype(np.uint8)
docs: Encode elevation value to RGB values compatible with Mapzen tangram.
  
      Attributes
      ----------
      arr : numpy ndarray
          Image array to encode.
  
      Returns
      -------
      out : numpy ndarray
          RGB array (3, h, w)