The calculated distance (air line) between Goyang-si and Gwangmyeong is approximately 13 miles respectively 20 kilometers.
By car or train, the actual journey to Gwangmyeong is certainly longer, as only the direct route (as the crow flies) between Goyang-si and Gwangmyeong has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles