The calculated distance (air line) between Yeonggwang and Seongnam-si is approximately 153 miles respectively 247 kilometers.
By car or train, the actual journey to Seongnam-si is certainly longer, as only the direct route (as the crow flies) between Yeonggwang and Seongnam-si has been calculated here.
Air line (approximately)
247 kilometers
133 nautical miles