Data & credits

These sources support commercial reuse under the terms identified below. We credit the source organizations, link the licenses and describe the calculations that changed their data. No source organization sponsors or endorses this game.

Download the source and commercial-use register · Detailed measurement documentation · Dataset metadata

CC BY 4.0 license permits sharing and adaptation, including commercial use, with attribution and notice of changes. CC0 1.0 is a public-domain dedication.

Sources and licenses

• GeoNames: city names, identifiers and coordinates; CC BY 4.0. We selected 205 cities, projected their coordinates and derived hemispheres.
• Natural Earth 1:10 million: public domain. Made with Natural Earth. We simplified and cropped the land map, used a Miller projection and calculated geographic distances with WGS84 geodesics. International land boundaries were filtered as documented.
• NOAA ETOPO 2022 v1: CC0 metadata. Point surface elevations were extracted and converted for unit display.
• NASA POWER / MERRA-2: attribution retained under the MERRA-2 CC BY 4.0 listing. Climate data accessed October 25, 2026, covering 2001–2025. We derived monthly averages, annual precipitation and seasonal temperature differences. See POWER referencing guidance.
• ESA WorldCover 2021 v200: CC BY 4.0. We calculated tree-class area fractions within 20 km. © ESA WorldCover project 2021 / Contains modified Copernicus Sentinel data (2021) processed by ESA WorldCover consortium.
• GHS-POP R2023A, E2020 1 km: CC BY 4.0. We aggregated population within 25 km and calculated density. Both the data product and required reference publication are cited below.

Dataset and publication citations

• 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. 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.
• Zanaga et al. (2022), ESA WorldCover 10 m 2021 v200, doi: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. 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.
• The climate data was obtained from the NASA Langley Research Center Prediction Of Worldwide Energy Resources (POWER) project, funded through the NASA Earth Science Division, using the POWER Climatology API v2.10.1 on October 25, 2026. Source: MERRA-2, January 2001–December 2025. The service name and version were verified in all 205 saved response headers.

Interpretation and limitations

Clues describe stored reference measurements. Temperature is a long-term monthly mean, not current weather. Population represents a 2020 modeled grid, and tree cover a 2021 land-cover classification. Surrounding-area statistics are not administrative-city totals. Geographic distances use generalized mapped features and are not travel distances.

The map and measurements are simplified for a recreational puzzle. Small features can be absent. Geographic names and boundary choices do not express a political position. Agency names identify sources; no logos or endorsement rights are granted.

Fictional scenario and geographic information

Ten Shields – One Earth is a fictional scenario created solely for entertainment. The alien invasion, attacks and defenses do not describe real events or threats. City markers, names, borders, boundaries and measurements are simplified game representations. They make no claim to precise city positions, complete or current information, official boundary status, sovereignty or territorial rights, and do not express a political position.

Thaalam Games does not guarantee the accuracy, completeness or currency of the geographic information. Do not rely on this game for navigation, emergency response, scientific, legal or other real-world decisions. To the extent allowed by applicable law, Thaalam Games is not liable for errors or omissions in this information or losses arising from reliance on it.

Artwork and game presentation

The spacecraft illustration and shield icon in this web release are original vector artwork created for this game. The map derives from Natural Earth.