Reborder map data sources

The bundled game puzzles are independently derived from public geographic datasets.
They do not contain assets downloaded from reborder.app.

Country boundaries:
  world-atlas 2.0.2, countries-10m.json
  https://github.com/topojson/world-atlas
  Source: Natural Earth 4.1.0, 1:10 million Admin 0 country boundaries.
  Natural Earth data is public domain: https://www.naturalearthdata.com/about/terms-of-use/
  The redistribution package is ISC licensed; see world-atlas.txt.

US state boundaries:
  us-atlas 3.0.1, states-10m.json
  https://github.com/topojson/us-atlas
  Source: US Census Bureau cartographic boundary shapefiles, 2017 edition.
  The redistribution package is ISC licensed; see us-atlas.txt.

Processing:
  scripts/generate-game-data.mjs uses topojson-client 3.1.0 and d3-geo 3.1.1
  to extract adjacency, merge mainland polygons, extract their common boundary,
  project to a 600 by 600 drawing surface and simplify in screen coordinates.
  Offshore islands, detached territories and unsuitable multi-section or short
  borders are excluded to make a continuous border drawable on a small screen.

This historical, generalized dataset is used for a geography game. It is not an
up-to-date or authoritative statement about territorial boundaries or sovereignty.

WORLD-ATLAS LICENSE

Copyright 2013-2019 Michael Bostock

Permission to use, copy, modify, and/or distribute this software for any purpose
with or without fee is hereby granted, provided that the above copyright notice
and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.

US-ATLAS LICENSE

Copyright 2013-2019 Michael Bostock

Permission to use, copy, modify, and/or distribute this software for any purpose
with or without fee is hereby granted, provided that the above copyright notice
and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.