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# Map minting guidelines

## 1. Artifacts are never committed
- Routing tiles and basemaps are large binaries rebuilt from upstream. This repo
  holds the scripts that produce them and a report of the procedure, nothing else.  
- Every build records the source PBF's date. An artifact whose provenance is
  unknown is an artifact to rebuild.

## 2. Build the admin database first
- `valhalla_build_admins` is what determines driving side, and it is a separate
  step *before* the tile build.  
- Skip it and Valhalla routes and narrates as though Japan drove on the right.

## 3. Tiles ship as a directory, not a tar
- Once for RAM on an 8 GB board, once because `rsync` deltas a tree of changed
  files where a multi-gigabyte tar forces a full checksum at both ends.

## 4. To be added