The calculated distance (air line) between Yŏnan-ŭp and Gwangmyeong is approximately 49 miles respectively 78 kilometers.
By car or train, the actual journey to Gwangmyeong is certainly longer, as only the direct route (as the crow flies) between Yŏnan-ŭp and Gwangmyeong has been calculated here.
Air line (approximately)
78 kilometers
42 nautical miles