Mapping the Moon
This is an exploratory study in mapping the moon and all the implications it entails in order to achieve a map of the moon within OpenStreetMap.
The moon is an oblate spheroid, like the Earth; however, it is unlike the Earth in that it is much smaller and with a different geoid -- or if you will, lunoid -- so the default projection most OSM software assumes (WebMercator) does not apply. Changing the projection stack may be an opportunity to use a seamless geodesy (lunadesy) scheme, avoiding such problems as those analogous to 180th meridian and others.
A lunar planet file (er, satellite file) would likely be much smaller than the Earth's.
Currently OSMwiki is being used for this brainstorming; however, another wiki host may be more suitable in the future.
For mapping the earth there is no need to add features based on a geologic time scale as it wouldn't add much to the existing database. After all we don't recognize natural features based on their Archean or Proterozoic age but based on how they look.
However differentiating between different terrain types based on how they look is a lot more difficult for the moon because the features can look alike and are difficult to survey.
We could use the geologic timescale (selenolical timescale) in combination with how the natural features look as a way to differentiate between various terrain types.
This would be fairly similar to the 'Unified Geologic Map of the Moon' from the Department of the Interior United States Geological Survey found here.
Maria (lowlands) Terrae (highlands)
Pre-Nectarian / Nectarian / Early Imbrian / Late Imbrian / Eratosthenian / Copernican
There is a list of artificial objects on the Moon with coordinates that may be mapped. Possible tagging: man_made=spacecraft with status tags condition=intentionally_crashed, condition=crashed, condition=not_operational, condition=operational.
OSM uses a Pseudo-Mercator projection where the Earth is modelized as if it was a perfect a sphere1.
The moon is 27% the size of the earth, would this Pseudo-Mercator projection give a satisfactory map display of the moon?
The background colour used for earth is
#F2EFE9, this is a neutral colour without any specific relation to any earth-like looking colours.
For the moon there is a distinct grayscale colour scheme we could use as a default background colour.
Based on photo's from the moon 4 hex values have been chosen as possible colours, these examples are from light to dark:
- Would a moonlike colour be preferred or a more distinct colour in order to be able to visually detect incorrect or missing geodata?
- And if so would
#F2EFE9be distinct enough?