Topo Heli

A browser topography game: fly a helicopter over a map and find as many cities as you can before time runs out.

npm install
npm run dev      # http://localhost:5173
npm run dev:lan  # http://localhost:5180, also reachable from a phone on the same network
npm run build    # static site in dist/

# with dev:lan running (needs Google Chrome):
npm run playtest # plays a map through and reports problems
npm run shots    # screenshots of menu, game and end screen (desktop + phone) in .shots/

How it plays

• Arrow keys / WASD to fly. On touch screens, drag anywhere to get a virtual joystick.
• Fly within range of the city and a flashing dot appears; fly over it to score.
• You start with 3:00. Every 10 cities: +1:00 and the next level. Each level adds smaller towns to the pool and the dot appears later (smaller reveal radius).
• N skips a city (−10 s), P/Esc pauses, M toggles sound.

Mountains, rivers & lakes (Serbia) / Waters (Netherlands and provinces: rivers, canals, lakes and seas from the basislijst topografie) / Mountains, waters & areas (Germany: also the Länder, landscapes and islands); switch on the start screen: physical features are mixed in with the cities. Lakes and mountains are found by flying over them. Rivers are found by following them: the bar fills with the length of river you have flown along (40 km, or 60% of a short river); simply crossing a river covers only ~8 km. Best scores are kept per map and mode.

Languages: English, Dutch, Serbian Latin and Serbian Cyrillic (flag menu on the start screen; the default follows the browser's language list, falling back to English). UI text lives in src/i18n.ts; Serbian is written once in Latin script and transliterated to Cyrillic. Place names: Serbia uses its (Serbian Latin) names, Europe has Serbian and Dutch names in src/maps/europe/names.sr.json / names.nl.json, Dutch town names are kept as-is, Germany uses German names with English, Dutch and Serbian ones in src/maps/germany/names.{en,nl,sr}.json.

Tuning lives in src/config.ts.

Provinces (Netherlands) / regions (Serbia, Germany): pick one in the list under the map buttons to play only that part: its map, its places (capital always in level 1) and, where there are any, its rivers. German regions are the Länder, with Hamburg, Bremen and Berlin inside the Land around them.

Adding a map

1. Add an entry to MAPS in scripts/build-map.mjs: the Natural Earth country codes that form the playable area, a bounding box, and how to group the internal borders.
2. Run npm run build:map -- <id>. This downloads Natural Earth data into .cache/ and writes src/maps/<id>/geo.json. Optional settings there: projection (equal-area, for large regions), colorCountries (a colour per country with clear borders) and merge (draw a territory as part of a country).
3. Add src/maps/<id>/cities.json: { name, lat, lon, pop, level? }. Population decides which cities appear at which level; level puts a city in play from that level regardless of size (used for capitals).
4. Register the map in src/maps/index.ts (viewKm sets the zoom level: larger regions want a larger value).

Physical features

Dutch places and provinces: the curated list is data/netherlands-cities.json; npm run build:places adds municipality seats (OpenStreetMap) and villages of 2,000+ inhabitants (GeoNames) and writes the per-province lists. In the whole-country map the added places only come up from level 6. Build order after changing map data: build:map → build:places → build:physical. Province definitions: scripts/provinces.mjs.

German places: towns and cities from OpenStreetMap (population from GeoNames where OSM has none), 20,000+ inhabitants on the whole map, 10,000+ on the region maps. The Find them all list (60 places, with 40 waters, mountains and areas: 100 names) and the translated names are in data/germany.json; the places are based on the TopoSite list of Germany.

npm run build:physical queries OpenStreetMap (Overpass API) for the rivers, lakes and peaks listed in scripts/build-physical.mjs and writes src/maps/<id>/physical.json. Each feature has a level that decides when it can be asked.

Credits

Inspired by Topografie Nederland (Radarsoft, Commodore 64, 1984), whose helicopter game had the same idea: fly to a named place before time runs out; it appears as a pulsing dot once you are close.

Data

• Borders, rivers and lakes: Natural Earth (public domain). The Europe map uses the internationally recognised borders (Natural Earth's German point of view), with Kosovo drawn as part of Serbia on every map.
• Rivers, lakes and peaks, and the German towns and cities: OpenStreetMap contributors (ODbL).
• Dutch coastline and province borders: CBS / Kadaster via PDOK (CC BY 4.0): province areas minus the CBS "water" neighbourhoods, so islands and estuaries are separate.
• City coordinates: GeoNames (CC BY 4.0); for Germany only the population where OSM has none. Populations are rounded approximations.