mikkeli
8ee3d4cde5
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
31 lines
1.4 KiB
Markdown
31 lines
1.4 KiB
Markdown
---
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type: default
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---
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# Map minting guidelines
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## 1. Artifacts are never committed
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- Routing tiles and basemaps are large binaries rebuilt from upstream. This repo
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holds the scripts that produce them and a report of the procedure, nothing else.
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- Every build records the source PBF's date. An artifact whose provenance is
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unknown is an artifact to rebuild.
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## 2. Build the admin database first, and from the *full* extract
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- `valhalla_build_admins` is what determines driving side, and it is a separate
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step *before* the tile build.
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- **Always build it from `japan-latest.osm.pbf`, never a sub-region.** Driving side
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is a country-level property. A Shikoku extract yields only `admin_level=4`
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prefecture rows, no country record, and `drive_on_right=1` on every one —
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measured, not theorised.
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- The admin build and the tile build are separate invocations against the same
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config, so routing tiles may still come from a small regional extract while the
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admin database comes from the whole country.
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- **Verify, do not assume.** Every build checks that a country-level row exists and
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reports `drive_on_right=0` before the tiles are considered usable. This failure
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is silent otherwise: routing simply comes out mirrored.
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## 3. Tiles ship as a directory, not a tar
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- Once for RAM on an 8 GB board, once because `rsync` deltas a tree of changed
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files where a multi-gigabyte tar forces a full checksum at both ends.
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## 4. To be added
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