The USGS is amazing. They have incredibly detailed information for the US: elevation (within 10 ft in many places), demographics, geology, and others. They have an amazing geologic map for Big Bend National Park [1] (a very geologically interesting park in southern Texas). Global maps are a lot harder to come by, unfortunately, although I did find a similar geologic map of the Earth as the one for Mars (divided by pieces) at [2].
The USGS really is great. It's one part of my government that I'm very proud of.
Here's a file I found a while back. Not Mars related, but pretty amazing. The national file is a delimited txt file with just about every geographical point of interest in the U.S. I've imported it into a SQL database and now run queries against it when I'm looking for a weekend road trip.
It's "NationalFile_20140601.zip - Download all national features in one .zip file "
I can't think of a way to query wikipedia - not like this allows. Once this file has been imported into sql (I use SQL Server), I run queries like
SELECT DISTINCT [feature_type] FROM dbo.nationalFile WHERE [state] = 'California'
This will give me a list of all types of features in California. From there, I'll see something that looks interesting (like "lava field" or "mine") and I'll run another query like
SELECT [feature_name], [latitude], [longitude] FROM dbo.nationalFile WHERE [state] = 'California' AND feature_type='lava field'.
This will give me a very clear list list. I can't imagine there would be a way to do this with Wikipedia, or any other online source that doesn't offer an API.
This map is certainly very interesting, but it suffers as a visualization. The topographical map is nice, due to its simplicity and well-chosen color scale, but the main geological map certainly has some problems.
The biggest problem is that they are choosing two represent two different dimensions of data(age/time period and terrain type), but are using seemingly random variations of hue to show these variations. Additionally, with so many distinct hues, it is nearly impossible to tell the difference between some areas on the map (for example, Hesperian basin unit and Hesperian polar look very similar).
A more effective way to visualize this data would be to apply a separate hue to the 8 categories of terrain unit, since these are categorical data points. Then, visualize the geological age on a brightness scale, since this is more of a quantitative measurement (obviously the current map also show the particular time period, we'll just ignore that for now). I think this would provide a much clearer view of the data, though you would lose a small bit of granularity.
I'm not necessarily disagreeing with you, but here's some relevant explanation of their color choices which largely seem to have been chosen for consistency with previous publications:
Watching the individual shapes render on the PDF in Firefox's PDF viewer reminded me of fond memories of DOS-based mapping software I had as a kid on an 8MHz 8088 PC-XT with CGA graphics. Once upon a time, you actually had to wait for each individual vector shape to be drawn :-).
I just finished the second book myself and had the same thought. All the various escarpments and planae are hard to keep track of. There's a lot of geography in those books.
I am particularly fascinated by the small topological map. I like imagining what Mars would be like under Earth-like conditions - if a watery planet looked like that, how would people live? Where would the population be most concentrated? How would the political landscape be influenced by the geography?
I guess I spent too much of my childhood playing Role Master :-)
It's still working for me, but the big map is taking a long time to load. I expect they're having some trouble handling the influx of downloaders from the media attention.
[1] http://pubs.usgs.gov/sim/3142/
[2] http://energy.usgs.gov/OilGas/AssessmentsData/WorldPetroleum...