Files
tool-mapmint/docs/GUIDELINES.md
T
mikkeli 8ee3d4cde5 Correct admin build: must use full Japan extract, not a sub-region
Verified on the Orin. A Shikoku extract yields only admin_level=4 prefecture
rows with no country record, and drive_on_right=1 on every one, so tiles built
against it route as right-hand traffic. The full Japan extract yields the
JP country row with drive_on_right=0.

The failure is silent, so every build now verifies the country row before
tiles are considered usable.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013kj58Jugkic783b8ZrtTVZ
2026-09-04 10:56:03 +09:00

1.4 KiB

type
type
default

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, and from the full extract

  • valhalla_build_admins is what determines driving side, and it is a separate step before the tile build.
  • Always build it from japan-latest.osm.pbf, never a sub-region. Driving side is a country-level property. A Shikoku extract yields only admin_level=4 prefecture rows, no country record, and drive_on_right=1 on every one — measured, not theorised.
  • The admin build and the tile build are separate invocations against the same config, so routing tiles may still come from a small regional extract while the admin database comes from the whole country.
  • Verify, do not assume. Every build checks that a country-level row exists and reports drive_on_right=0 before the tiles are considered usable. This failure is silent otherwise: routing simply comes out mirrored.

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