The calculated distance (air line) between Changwon and Yangp'yŏng is approximately 170 miles respectively 273 kilometers.
By car or train, the actual journey to Yangp'yŏng is certainly longer, as only the direct route (as the crow flies) between Changwon and Yangp'yŏng has been calculated here.
Air line (approximately)
273 kilometers
147 nautical miles