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