Mariner images where used to select Viking landing sites. Viking images became the basis for determining the landing site of the Mars Pathfinder in 1997. They were made by way of radar altimetry. Recall that wavelengths shorten toward the gamma ray end and length on the radiowave side. Radar altimeters most often operate in the high microwave bands and laser altimeters in infrared wavelengths.
Greater detail can result by use of a shorter wavelength.
In our investigation we will be working with topographic data returned from the MOLA instrument. Data sets are often compressed horizontally so they take less space and graph more easily. We will need to keep this in mind. The graph below serves as an example. This ratio means that the vertical is exaggerated 100 times for each unit on the horizontal.