Offline map packs
build_pack.py downloads a small OpenStreetMap tile pack for the SD card.
python build_pack.py --bbox 55.70,37.40,55.95,37.90 --zoom 10-14 \
--out D:\ --name Moscow
--out is the card root; the script creates:
D:\maps\osm\<z>\<x>\<y>.png
D:\maps\osm\packs.json
D:\maps\osm\packs.txt
Copy maps to the microSD card and enable Tiles from SD card in the map
options. packs.json records name, bbox, zooms, tile count and size; it is
metadata for now and is safe to keep alongside the tiles.
Use a bbox and zoom that match what you actually need — a city at z10–14 is a
few hundred tiles, not a country. The script sleeps between requests, skips
existing tiles and respects the tile server's User-Agent; do not use it for
bulk planet downloads.