ASA Go: Base Map Download

[conbrad]

Describe the task
Capacitor does not support reading file assets from app assets built into apps. Instead we can follow the approach InvasivesBC used for their offline maps, and, when online:

1. Query the pmtiles header for extent and size of basemap
2. Request all z, x, y tiles and store them in a sqlite database: https://github.com/bcgov/invasivesbc/blob/dev/app/src/utils/tile-cache/sqlite-cache.ts
3. Provide feedback to the user of the download status

Acceptance Criteria

• A user can download the pmtiles basemap when connected to the internet

Additional context

• https://github.com/bcgov/invasivesbc/blob/dev/app/src/utils/tile-cache/sqlite-cache.ts
• Created from ASA Go: Base Map [ TIMEBOX = 3 DAYS ] #4159