The Topography of Asteroid Ida: A Comparison between Photogrammetric and Shape­Form-Shading Image Analysis

We derived high resolution Digital Terrain Models from stereo images of the asteroid Ida that were obtained by the Galileo spacecraft during the flyby in August 1993 and compared these results with terrain models derived from two-dimensional photoclinometry. The comparison shows that there are striking discrepancies between the results from the two models depending on the spatial scale length of surface features. While photogrammetry resolves large- and medium-scale features, photoclinometry successfully resolves small-scale features. Ideally, both methods should be combined to optimize terrain modeling.