Busan clears as a ribbon, not a blob
FOG hides the whole map until you walk it. Busan is thirty kilometres of city wedged between mountains and the sea, so it comes off in strips.
A city with no middle
Busan does not have a single centre and never really did. The mountains push the built area into valleys and along the coast, so the city runs as a long strung out line, roughly thirty kilometres from Haeundae in the east to the Nakdong river in the west. Seomyeon is the commercial middle, Nampo-dong and Jagalchi are the old port core, Haeundae and Gwangalli are the beaches, and Yeongdo is an island bolted on by bridges.
On a fog map that geography is unmistakable. You do not build a spreading blot the way you do in a flat inland city. You build a ribbon along the water with side branches climbing into the valleys behind it.
Stairs are streets here
The other thing about Busan is vertical. Whole neighbourhoods sit on slopes no car can take, so the connections are staircases, and there are thousands of them. Gamcheon Culture Village is the famous example, layered houses on a hillside with alleys threading between them, but Choryang, Ami-dong and the slopes above Nampo work the same way without the crowds.
Those alleys matter for a fog map because most of them are not on any driving route. If you only walk the flat main roads along the bottom of each valley, you will leave everything behind and above them completely dark, and that is a very large amount of ground.
A coastal afternoon
Try this one. Start at the west end of Gwangalli beach with the Gwangan Bridge in front of you and walk the full sand and promenade east, then continue around into the Igidae coastal trail. It is boardwalk and rock path along the cliffs with the bridge behind you the whole way, and it finishes near the Oryukdo Skywalk. Six to eight kilometres depending on where you turn back.
For the opposite kind of day, walk Jagalchi fish market, the Gukje Market lanes and the Bosu-dong book alley, then climb toward Gamcheon. Short distance, dense streets, and a lot more map cleared per kilometre.
High rises and wandering GPS
An honest note. Marine City and the tower cluster in Haeundae are high rise canyons, and phone positioning wanders in them. The same thing happens in the tight streets under the hills where buildings sit close on both sides and the sky is a narrow strip. If a track looks like it drifted through a building, that is why, and it is a phone problem rather than a Busan problem.
Coastal walking is the cure. Along the water the sky is wide open and the trace stays tight against the path you actually took.
Seasons, typhoons and what the app does
Summers are hot and humid, and the typhoon season runs from late summer into early autumn, when the coastal paths sometimes close outright. Winters are cold but noticeably milder than Seoul, and dry, which makes them good for long days on foot. Spring and autumn are the obvious picks.
FOG does nothing city specific here. It is the same world map everywhere, hidden until you walk it, and only the streets differ. Every street you cover is revealed permanently, the map stays on your phone with no account and no cloud, and background exploring keeps it recording with the screen off.
Questions people actually ask
Will the hillside alleys register?
If you physically walk them, yes. They are the part of Busan most people never cover, so they are worth the climb.
Why does my track wobble near Haeundae?
Dense high-rise clusters bounce satellite signals and phone positioning drifts. Open coastal stretches give a much cleaner trace.
Does FOG work for running and cycling too?
Yes. Walking, running and riding, anywhere on Earth.
Is any of this uploaded anywhere?
No. No account, no sign-up, no cloud, no analytics, no ads and no tracking. The map never leaves the phone, and you can export your own data.
What do I get for the purchase?
One payment of USD 5.99 unlocks unlimited ranks, every character and history import. It is free to explore before that, and there is no subscription.
Start with a dark map.
FOG is free to explore. No account, no subscription, and your map never leaves your phone.
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