convert a bytestring into a 2D row x column array, representing an existing map of fog-of-war, creep, etc.

def convertToMapPic(byteString, mapWidth):
    """convert a bytestring into a 2D row x column array, representing an existing map of fog-of-war, creep, etc."""
    data = []
    line = ""
    for idx,char in enumerate(byteString):
        line += str(ord(char))
        if ((idx+1)%mapWidth)==0:
            data.append(line)
            line = ""
    return data