     clusterIdMap.getPixel x, y
 
   pixelExists: (x, y) ->
+    return unless @_bounds
     @pixelExistsRelative x - @_bounds.x, y - @_bounds.y
 
   pixelExistsRelative: (x, y) ->

    mapValues

  _relativeCoordinateInBounds: (x, y) ->
    0 <= x < @_bounds.width and 0 <= y < @_bounds.height
    
  getClusterIdForPixel: (x, y) ->
    @getClusterIdForPixelRelative x - @_bounds.x, y - @_bounds.y

  getClusterIdForPixelRelative: (x, y) ->

    @maps[type]

  getMapValuesForPixel: (x, y) ->
    return unless @_bounds
    @getMapValuesForPixelRelative x - @_bounds.x, y - @_bounds.y

  getMapValuesForPixelRelative: (x, y) ->
