A majority of the people who work in planetary geology are usually associated with one or maybe two missions, doing all their research on the results from one instrument on one mission. But there are a few people whose expertise cuts across many space missions, and an even smaller number of people who seem to work on almost everything. Randy Kirk is one of those people; he works at the United States Geologic Survey, and specializes in the challenges of mapping the topography of planetary surfaces. His and his coworkers' methods, honed over many years, allow them to create topographic maps (and, nowadays, digital elevation models) of places on planets even when they don't have actual topographic data. They do it, most often, through a technique called photoclinometry, also known as shape-from-shading.
Having good topographic information is important for many different lines of scientific research, but you can probably appreciate that it is of critical importance for conducting a rover mission. Randy's digital elevation models provided the Mars Exploration Rover teams with the information they needed to determine where around the rim of Victoria crater Opportunity should attempt to descend into the crater's interior, and also where Spirit could find winter havens with exactly the right northward-tilting slopes, steep enough to maximize the sunlight falling on the rover's solar panels, without being so steep that the rover might be in danger from sliding.
Some of these digital elevation models have been posted to the United States Geological Survey website. These are not data products that most of us can do much with. Fortunately, there are people out there like Doug Ellison who can turn these technical data into something very, very pretty. He took the topographic information for the Spirit and Opportunity landing sites and turned them into some lovely flyovers of the terrain, including little models of the rovers for scale. Enjoy the ride! The lower-resolution videos will probably be sufficient for most of you; the higher-resolution versions are high-definition.
» Fly over the Columbia hills and Spirit (medium resolution, 12 MB)
» Fly over the Columbia hills and Spirit (high resolution, 65 MB)
» Fly over Victoria crater and Opportunity (medium resolution, 5.4 MB)
» Fly over Victoria crater and Opportunity (high resolution, 13 MB)
I realize that these are not very friendly to those of you who are stuck with low-speed connections. I'll make a mental note to find some pretty pictures to post this week that don't require you to be able to download Megabytes of material.