Offline area downloads may violate OSM tile usage policy

[dougborg]

Context

The OSM tile usage policy explicitly prohibits:

No "download for offline" features or background prefetch jobs

No tile archive creation (.zip, .mbtiles) for later distribution

Current behavior

The app's offline area feature (offline_area_downloader.dart) downloads tiles from tile.openstreetmap.org and stores them locally for offline use. Safeguards exist (50k tile max, min zoom 10, 7-level zoom span limit), but the feature itself is prohibited by the policy when sourcing from OSM's tile servers.

Options

1. Use a self-hosted or commercial tile server for offline downloads instead of tile.openstreetmap.org
2. Use vector tiles — the policy notes vector tile providers may permit offline packaging under their own terms
3. Remove offline tile downloads and rely on the in-memory cache only
4. Contact OSMF to discuss whether the existing safeguards are sufficient for a small-scale mapping app

References

• lib/services/offline_areas/offline_area_downloader.dart
• lib/dev_config.dart (tile count limits)
• Policy: https://operations.osmfoundation.org/policies/tiles/