Analog Finder

Where on Earth is most like a landing site on the Moon or Mars? Pick a target. The map ranks every patch of Earth's land, about 5 km across, by how closely it matches.

Similarity map Only new sites Exclude China

Best Earth analogs

at least 200 km apart · tick up to 3 to compare

Rank on Earth = place among all ranked land cells (5 km each). Ranks jump because cells next to a better site are skipped.

Compare	#	Country	Environment	Rank on Earth	Strongest	Weakest

Why this match

Feature by feature

Each dimension score is the weighted mean of its features; hover a match bar for its weight and reliability grades.

Why this environment class

How it works

The idea

Every target site on the Moon or Mars gets a fingerprint: terrain, surface material, temperature, dryness, atmosphere, dust, ice and sunlight. Every patch of Earth's land gets the same fingerprint from NASA and ESA data. The finder ranks Earth by how closely each patch matches, and shows for each match where the analogy holds and where it breaks.

Comparing different worlds

Same quantity, same method (terrain): value against value. Slope and relief are computed with the same code on all three bodies, at the target's resolution (100 m Moon, 463 m Mars).
Different instruments (thermal inertia, albedo): rank against rank. A site that is rockier than 41 % of Mars is matched with Earth land that is rockier than 41 % of Earth's bare ground.
Out of Earth's reach (vacuum, 6 hPa, −170 °C): the closer Earth gets, the better. No place on Earth reaches these values.
Every value carries a reliability grade (A direct measurement, B coarse or proxy, C rough estimate) that sets its weight.

Data

Earth, 2003–2024: NASA MODIS (surface temperature, albedo, vegetation, snow, land cover), NASA MERRA-2 (dust, dust storms, wind, pressure, precipitation), ESA Copernicus DEM (terrain, 90 m).
Mars: MOLA elevation (terrain), TES thermal inertia (NASA PDS).
Moon: LOLA polar elevation (terrain), Diviner polar resource product (temperature, ice stability) (NASA PDS).
Country names: Natural Earth (de-facto borders; disputed areas are marked).
‘Exclude China’ removes every 5 km cell inside China's de-facto borders (with Hong Kong and Macau) and re-ranks the list, for missions where fieldwork there is not possible. The match scores themselves do not change.

Limits

No place on Earth has the Moon's vacuum, Mars's thin CO₂ air, their low gravity or their radiation.
Target sites are 10 × 10 km (Mars) and 15 × 15 km (Moon) boxes around published coordinates, many of which are approximate.
Some Mars values (temperature, ice) are rough estimates for now; albedo, dust and ground ice for Mars are not yet included.
Dust, wind and pressure on Earth come from a 55 km reanalysis grid: regional, not local.

Coverage of the challenge's dimensions

Terrain, slope, relief	covered (craters as a separate feature: not yet)
Temperature, sunlight, extremes	covered
Dust, wind, storms	covered on Earth; Mars dust not yet
Surface material	partly: albedo, thermal inertia, environment class
Water, ice, permafrost	partly: snow, cold, ice stability (Moon)
Landing, mobility	partly: flat area, slope, substrate
Biology, habitability	weak: vegetation-free, hyperarid
Caves, lava tubes	not covered (no global data)