Geographic data: Copyright OpenStreetMap contributors.
Both osm-source.json and city.json are provided under the Open Database License (ODbL) 1.0.
License: https://opendatacommons.org/licenses/odbl/1-0/
Attribution and contributors: https://www.openstreetmap.org/copyright
Retrieved: 2026-09-07
Source: https://api.openstreetmap.org/api/0.6/map.json?bbox=139.7393,35.6539,139.7515,35.6637

Modifications: local equirectangular projection around latitude 35.65858,
longitude 139.745433; selected roads, buildings, green/religious areas and
trees; clipped polygons and assembled multipolygon rings; excluded tower
footprint to avoid duplicating the original game model; height from height,
else levels * 3.2m, else placeholder 12m; road widths from width/lanes tags
or class defaults. OSM way/relation IDs retained.
Rebuild offline: node build-city.mjs
Additional source: 3D都市モデル（Project PLATEAU）港区（2025年度）を加工して作成。
https://www.geospatial.jp/ckan/dataset/plateau-13103-minato-ku-2025
https://www.mlit.go.jp/plateau/site-policy/
The distributed PLATEAU README permits choosing ODbL 1.0, which is used here.
Retrieved 2026-09-07. See data/plateau/README.md and manifest.json.
plateau-heights.json contains extracted measuredHeight and LOD0 outlines;
height-matches.json maps accepted one-to-one outline matches to OSM IDs.
651 city.json heights are enriched with PLATEAU values, retaining original
height/source and PLATEAU ID. These derived databases are also ODbL 1.0.
Reproduce: python extract-plateau.py; node match-heights.mjs; node build-city.mjs
This data license does not replace the separate licenses of Three.js or the
independent original tower model and game source code.

Terrain data is a separate GSI-derived dataset, not an OSM/PLATEAU dataset.
Source: 地理院タイル（標高タイル）を加工して作成。
https://maps.gsi.go.jp/development/ichiran.html
GSI terms (PDL1.0): https://www.gsi.go.jp/kikakuchousei/kikakuchousei40182.html
Retrieved: 2026-09-08. Applies to assets/terrain.json and cached PNG DEM tiles
in data/terrain/ (also assets/terrain-sample.png, an initial sample of the same source).
Modifications: PNG elevation decoding, bilinear resampling onto a local 10m
grid. Runtime: tower-origin vertical offset, tower pad flattening/blending,
triangular surface construction, terrain-conforming roads/parks and foundations.
See data/terrain/README.md and manifest.json for details and original URLs.