compress_x = [0, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535, 131071, 262143, 524287, 1048575, 2097151, 4194303, 8388607, 16777215];
compress_y = [0, 63, 109, 187, 321, 551, 945, 1621, 1646, 1688, 1760, 1885, 2098, 2463, 2511, 2593, 2733, 2974, 3387, 4095];
