Map Viewport

Tile-based slippy map centred on the device's GPS position, rendered with Leaflet and OpenStreetMap tiles.

Live map

The blue dot tracks the device position. Follow mode keeps the map re-centred on every GPS update. Disable it to pan freely.

Zoom —

Centre —

GPS waiting…

Accuracy —

Tile coordinates. At zoom level Z, the world is divided into 2^Z × 2^Z tiles. A tile is addressed as Z/X/Y. The formula: X = floor((lng+180)/360 × 2^Z), Y = floor((1 − ln(tan(lat)+sec(lat))/π) / 2 × 2^Z). Leaflet handles this automatically — this test verifies the tile load latency and cache behaviour under movement.

Tile coordinate inspector

Shows the tile address for the current centre at each standard zoom level — useful for pre-caching a radius of tiles for offline play.

Pan the map or get a GPS fix to populate.