Kde je metro? — Prague Metro Guesser
Where does the Prague metro actually run? You get an aerial photo of a piece of Prague and a station name, and you draw the line where you think the platform lies underground. The closer your line is to the real track axis, the more points you get.
Play: https://kdejemetro.guth.workers.dev
Game modes
- Weekly challenge — 10 stations, the same for everyone in a given ISO week, public leaderboard.
- Training — random stations, no leaderboard.
- Live duel — 1v1 in real time: same 10 rounds, shared timer, round-by-round reveal.
- Hardcore — no station name, randomly rotated map, three lives, endless.
How it works
- Ground truth from OpenStreetMap. A build script pulls all metro stations and
railway=subway tracks from the Overpass API and clips the track axes around each station. Nothing is hand-placed.
- Scoring. Your line is sampled every 5 m and compared to the real axis with a symmetric mean distance
d; a round scores round(1000 × exp(−d / 85)).
- Deterministic weekly seed. Client and server derive the same stations and map offsets from the ISO week, so there is no cron and no weekly rebuild.
- Imagery. ČÚZK orthophoto WMTS (open data), Esri World Imagery as a fallback.
- Admin. Stats, guess heatmaps, player reports and per-station axis overrides stored in the database.
Stack
Vanilla JS + SVG frontend (no framework), a single Cloudflare Worker, Cloudflare D1, and Durable Objects for duel lobbies and matches.
Running locally
npm install
npm run migrate:local # create the local D1 database
npm run dev # wrangler dev
npm test # node --test
npm run smoke # duel smoke tests
npm run build:stations regenerates stations.json from OpenStreetMap. Deployment notes are in DEPLOY.md, design docs in docs/.
🇨🇿 Česky: Hádací hra nad leteckými snímky Prahy — nakresli, kudy pod zemí vede stanice metra. Týdenní výzva s žebříčkem, trénink, živý duel 1v1 a hardcore režim. Osy stanic se počítají automaticky z OpenStreetMap, snímky jsou ortofoto ČÚZK. Běží na Cloudflare Workers + D1.
