Convert from stadium to gigameter

Unit Definition (stadium)
The stadium is a historic unit of distance originating in ancient Greece. Greek athletic fields were all of roughly the same size, and the stadion, equal to 600 podes (feet), was the traditional length of the field. Archaeological measurements show that the stadion was a little more than 200 yards or a little less than 200 meters. The stadion at Olympia, where the original Olympic Games were held, measures 630.8 feet or 192.3 meters; at Athens the stadion was 606.9 feet or 185.0 meters. Stadium is the Latin spelling; in the Roman world the stadium was equal to 625 Roman feet (pes) or 1/8 Roman mile. This is equivalent to 606.95 feet, 202.32 yards, or 185.00 meters. The plural is stadia.

Unit Definition (gigameter)
The Gigameter (or Gigametre) a metric unit of distance equal to one million kilometers or about 621,371.2 miles. It is seldom used, but this unit would be a good yardstick for the inner Solar System: the distance from the earth to the sun is about 149.60 gigameters.