Seoul is not a flat, continuous grid. A broad river splits the metropolis while steep hills interrupt development on both banks, forcing streets and railways into a pattern of crossings, valleys and dense centers.
Three traces to read
The Han River
The exceptionally broad east–west river is the first clue. Islands, floodplains and many bridge crossings break up its long urban edge.
Mountains inside the city
Ridges rise close to the historic center and between districts, so the built-up area bends around hills instead of spreading as one uniform block.
Two banks, many centers
Radial railways, ring routes and repeated river crossings connect older northern districts with the large southern business and residential areas.
What usually gives Seoul away?
Look for the combination of a very wide river, a dense metropolis on both banks and mountains that remain visible as gaps in the street network. The river alone is not enough; the close-in terrain makes the fingerprint distinctive.
This guide is an editorial reading of the real map geometry used by URBANTRACE. Place names are removed during play. OpenStreetMap ↗