def get_rgbval(self, index):
        assert (index >= 0) and (index < 256), \
               RGBMapError("Index must be in range 0-255 !")
        index = self.sarr[index].clip(0, 255)
        return (self.arr[0][index],
                self.arr[1][index],
                self.arr[2][index])
Return a tuple of (R, G, B) values in the 0-255 range associated
dataset/ETHPy150Open ejeschke/ginga/ginga/RGBMap.py/RGBMapper.get_rgbval