I was trying and failing to put this in my own words, then I found this plain English summary of this doc... link1

Key data returned from robots exploring the surface of Mars are the images they take of the landscape and rock formations. These are sent back to Earth for detailed investigation and analysis by the science teams. It is difficult to collect reliable measurements from photographs, as they do not truly represent the three-dimensionality of the features within them. In this paper, we present a new 3-D visualization software tool, PRo3D, which enables visualization of 3-D digital models of rock outcrops imaged by robots exploring the surface of Mars. These 3-D models are constructed from mosaicked photographs taken by the stereo panoramic cameras which are positioned on a mast on the rover. This provides a huge advantage to scientists who want to study and analyze the terrain and geology of exposed rock outcrops which surround the rover. Here we apply the tools available in PRo3D to sedimentological and structural analysis of 3-D Digital Outcrop Models of four areas explored by the Mars Exploration Rover Opportunity and Mars Science Laboratory Curiosity rover science teams and show that this method of 3-D visualization and analysis allows scientists to carry out important procedures that would be conducted in a terrestrial field geology campaign.

anther good read.... link2