Trigo

A simple app for finding nearby triangulation stations within a chosen radius on Google Maps, using your current location.

Setup

1. Google Maps API key
   Get an API key from Google Cloud Console (enable “Maps JavaScript API”).
   Open index.html and replace YOUR_GOOGLE_MAPS_API_KEY with your key:

   const GOOGLE_MAPS_API_KEY = 'your-actual-key-here';

2. Serve the folder over HTTP
   Browsers block loading local files (e.g. trigdatabase.csv) from file://. Run a local server from the project directory. Any of these will work:

   # Python 3
   python -m http.server 8080
   
   # Node (npx)
   npx serve -p 8080
   
   # PHP
   php -S localhost:8080
   
   # Ruby
   ruby -run -ehttpd . -p8080

   Or use the Live Server extension in VS Code/Cursor (right‑click index.html → Open with Live Server).

   Then open http://localhost:8080 on your phone (same Wi‑Fi) or computer.

3. Location permission
   When you tap My location, the browser will ask for location access. Allow it so the map can centre on you and show nearby trig points.

Usage

• Choose Within (5, 10, 25, or 50 km).
• Tap My location to centre the map on you and show trig points in that radius.
• Tap a green marker to see name, type, condition, height, and distance.
• Blue circle is your position.

Data

Uses trigdatabase.csv (columns: lat, long, tp_num, tp_name, full_name, type, condition, height_m). The CSV is loaded once; filtering by radius is done in the browser with the Haversine formula.

The data currently used for this from Lonewalker's database: https://lonewalker.net/trigtable.php - I've not tested the correctness of this database, and it should be treated as such (see the disclaimer on that page).