# Commercial-use source register

The following register applies to `cities_game_metrics_205.csv`. License descriptions and source pages were checked on October 24–25, 2026. Reuse must retain appropriate source credit, identify derived calculations, and avoid suggesting endorsement by the source organizations.

| Source | License / commercial use | Evidence |
| --- | --- | --- |
| GeoNames city identifiers, names and coordinates | CC BY 4.0; commercial reuse permitted with attribution | [GeoNames](https://www.geonames.org/about.html) |
| Natural Earth 1:10 million geographic features | Public domain; expressly permits commercial use | [Terms of use](https://www.naturalearthdata.com/about/terms-of-use/) |
| NOAA ETOPO 2022 v1 surface elevation | CC0 1.0 public-domain dedication; commercial reuse permitted | [NOAA metadata](https://data.noaa.gov/waf/NOAA/NESDIS/NGDC/MGG/DEM/iso/xml/etopo_2022.xml), [product page](https://www.ncei.noaa.gov/products/etopo-global-relief-model) |
| NASA POWER meteorological climatology derived from MERRA-2 | Commercial reuse permitted. MERRA-2's NASA-managed open-data listing specifies CC BY 4.0; preserve source attribution and mark derived climatological calculations | [MERRA-2 license register](https://registry.opendata.aws/nasa-merra-2/), [POWER methodology](https://power.larc.nasa.gov/docs/methodology/meteorology/), [NASA data-use guidance](https://www.earthdata.nasa.gov/engage/open-data-services-software/data-use-policy) |
| ESA WorldCover 2021 v200 | CC BY 4.0; commercial reuse permitted with source/product acknowledgement | [Data-access and license page](https://esa-worldcover.org/en/data-access) |
| GHS-POP R2023A, E2020 1 km | CC BY 4.0; commercial reuse permitted; include both dataset citation and the GHSL reference publication | [GHSL use conditions](https://human-settlement.emergency.copernicus.eu/GHSLhowToCite.php), [product](https://human-settlement.emergency.copernicus.eu/ghs_pop2023.php) |

The NASA general data policy distinguishes NASA data from third-party restricted content. This dataset uses POWER's MERRA-2 meteorology only, as verified in every API response; it does not use commercial satellite imagery or restricted NASA vendor products. Attribution under the MERRA-2 CC BY listing is retained regardless of the general NASA public-domain guidance. No NASA logos or endorsement rights are granted.

## Credits to retain with derived data

- GeoNames geographical database, GeoNames, CC BY 4.0. Names and coordinates retained; hemispheres derived.
- Made with Natural Earth. Distances calculated from mapped features using WGS84 geodesics; the international-boundary feature class is filtered as documented.
- NOAA National Centers for Environmental Information (2022), *ETOPO 2022 15 Arc-Second Global Relief Model*, [doi:10.25921/fd45-gt74](https://doi.org/10.25921/fd45-gt74). Point elevations extracted from the surface model and converted to feet.
- NASA POWER Project at NASA Langley Research Center and NASA Global Modeling and Assimilation Office MERRA-2. POWER climatology accessed October 25, 2026; source period January 2001–December 2025. Derived annual precipitation and annual monthly temperature ranges. [POWER referencing guide](https://power.larc.nasa.gov/docs/referencing/).
- Zanaga et al. (2022), *ESA WorldCover 10 m 2021 v200*, [doi:10.5281/zenodo.7254221](https://doi.org/10.5281/zenodo.7254221). Derived class-10 tree-cover area fractions within 20 km. © ESA WorldCover project 2021 / Contains modified Copernicus Sentinel data (2021) processed by ESA WorldCover consortium.
- Schiavina, M.; Freire, S.; Carioli, A.; MacManus, K., *GHS-POP R2023A — GHS population grid multitemporal (1975–2030)*. European Commission, Joint Research Centre, [doi:10.2905/2FF68A52-5B5B-4A22-8F40-C41DA8332CFE](https://doi.org/10.2905/2FF68A52-5B5B-4A22-8F40-C41DA8332CFE). Used the E2020 1 km Mollweide grid; aggregated within 25 km and derived population density. The product page identifies the release as 2023; the current JRC catalog also records a 2026 metadata update.
- Pesaresi et al. (2024), *Advances on the Global Human Settlement Layer by joint assessment of Earth Observation and population survey data*. International Journal of Digital Earth 17(1), [doi:10.1080/17538947.2024.2390454](https://doi.org/10.1080/17538947.2024.2390454).

Source license pages and the GHSL product's own copyright file are retained under `provenance/`, with URLs and SHA-256 hashes in `provenance/license_page_manifest.json`. The NOAA landing-page request timed out; its official metadata XML was retrieved and contains the CC0 dedication. Product and source attribution remain required where specified; this register does not grant rights to agency trademarks or imply sponsorship.