Complex sentence: The player has the option of starting the city in a segment of any of three area sizes, in real measurement the smallest has a length of 1 kilometer on a side, and the largest has a length of 4 kilometers on a side.
Split into simpler sentences: The player has the option of starting the city in a segment of any of three area sizes. In real measurements, the smallest has a length of one kilometer on a side, and the largest has a length of four kilometers on a side.