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Geodata and elevation: attribution across a mixed licence set

The environment/ category is the most licence-diverse in this catalog. Fifteen entries span CC0, public domain, CC-BY-4.0, ODbL, CDLA-Permissive-2.0 and three different national agency terms. They all look like "free government data" and they do not carry the same obligations. This page is the shared guidance the per-entry notes assume.

Public domain does not mean no acknowledgement

This is the distinction that makes the category confusing. Four catalog sources are public domain and ask for nothing; three are public domain and ask to be acknowledged.

A request is not a licence condition. You are not in breach if you skip it. But the agencies are the reason the data exists, the ask is cheap to honour, and in the case of NASA the request comes attached to a rule you must follow anyway (no implied endorsement).

Catalog policy: when the publisher asks in writing, the entry records attribution_required: true and supplies an attribution_string, even where the legal status is public domain. The field records the obligation as the publisher states it, not a court's view of it. When the publisher asks for nothing, the field is false.

Source Licence Credit Why
etopo-2022 CC0 No Waived outright
nasadem CC0 No Citation urged, not asked as a condition
poly-haven, open-hdri CC0 No Waived outright
natural-earth public domain No Explicitly asks for no credit
usgs-earth-explorer public domain No No standing request
gebco public domain Yes Compilation group asks users to acknowledge the source
nasa-3d-resources public domain Yes NASA asks to be credited and forbids implied endorsement
esa-worldcover CC-BY-4.0 Yes Licence condition
ms-building-footprints CDLA-Permissive-2.0 Yes Notice must travel with the data
copernicus-dem-glo30 custom Yes Specific wording required by the terms
jaxa-alos-aw3d30 custom Yes Agency terms require the credit line
openstreetmap ODbL Yes Licence condition, see below
opentopography varies Yes Per dataset; cite the landing page too

Each entry carries the exact string to use. Copy it from the entry rather than inventing wording, because two of these (Copernicus and JAXA) specify the form.

ODbL and OpenStreetMap: the share-alike does not reach your game

ODbL is the only copyleft licence in this category and the one people most often over-read. It distinguishes the database, a derived database, and a produced work.

  • Rendering OSM data into a level mesh, a texture, a navmesh, or a baked terrain makes a produced work. Your game is a produced work. The share-alike does not force you to open your game, your source, or your assets.
  • Reshaping the data and shipping the data makes a derived database. That is what triggers the share-alike. Exporting a trimmed .osm extract into your build and letting players read it is the case to watch.
  • Either way you must credit: © OpenStreetMap contributors, visible somewhere a player can reach.

The practical rule: bake it and you are fine, ship it and you have obligations.

Heightmaps are derived works of the elevation data

A terrain heightmap exported from a DEM carries the DEM's terms. It stops looking like geodata the moment it is a greyscale PNG, and the obligation does not stop with it. If the source needed a credit line, the credit follows the heightmap into your build.

This matters most for copernicus-dem-glo30 and jaxa-alos-aw3d30, whose custom terms require specific wording, and least for etopo-2022 and nasadem, which are CC0.

Where the credit goes

One reachable place is enough. In order of what works:

  1. A credits screen or an in-game "Attributions" panel.
  2. A CREDITS.txt or third-party-licences.txt shipped with the build.
  3. The store page, only as a supplement. Not sufficient on its own for ODbL, because a player who has the game should be able to find the notice.

Group them. One "Map and elevation data" block listing every source is easier to maintain than a line per asset, and satisfies all of the above.

Do not scrape

Google Maps, Bing Maps, Apple Maps and their elevation endpoints are not free geodata sources, whatever a tutorial says. Their terms prohibit deriving and redistributing content, and a scraped heightmap is the clearest possible case of that. Use the sources in this catalog. See high-risk.md.

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