Wisp street tiles, grid v1/q4 -- how the published database was built
=====================================================================

Published build: 157,959 tiles, built 2026-09-15T20:08:37Z.
Source: OpenStreetMap data from Geofabrik's North America extract
(replication timestamp 2026-09-14T20:21:51Z).
Licence: ODbL 1.0, (c) OpenStreetMap contributors.

The two Python files next to this one are the build scripts, at the
commit that produced the published tiles. They were edited for
publication only to replace a contact address and remove a local
interpreter path from the usage text; the logic is unchanged. Their
comments refer to internal design notes and review passes that are not
published; the code does not depend on them.

Requirements: Python 3 with pyosmium, and osmium-tool (1.19.1 was used).

1. Download the extract and its boundary:
     https://download.geofabrik.de/north-america-latest.osm.pbf
     https://download.geofabrik.de/north-america.poly

2. Keep only the ways the tiles use:
     osmium tags-filter -O -o na-roads.osm.pbf north-america-latest.osm.pbf \
       w/highway w/waterway w/natural=water w/landuse=reservoir,basin

3. Attach node locations to the ways:
     osmium add-locations-to-ways -i sparse_file_array,$PWD/na_nodes.idx \
       -O -o na-roads-loc.osm.pbf na-roads.osm.pbf

4. Build the tiles (build_basemap.py must sit next to build_tiles.py):
     python3 build_tiles.py --pbf na-roads-loc.osm.pbf \
       --poly north-america.poly --out na_out --index none

   The output directory holds v1/q4/<row>/<col>.wbm.gz and manifest.json.
   python3 build_tiles.py --self-test runs the script's own checks.