Geomorphometric analysis of Hebes Chasma, Mars, using the GRASS GIS.
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This research addressed the local scale geomorphometric analysis of the Hebes Chasma region on Mars, utilising a new 50 m/pixel digital terrain model derived from stereo imagery. A secondary aspect of the research addressed the role of GIS in performing geomorphometric analyses, specifically utilising the open source Geographic Resources Support System (GRASS) GIS. Two areas within Hebes Chasma were chosen for focussed study. Geomorphometric analyses performed over these areas included the derivation of slope gradient and direction, profile curvature, erosional flow and surface roughness. Additionally, elevation profiles were created and a limited hypsometric assessment was carried out. These results were used as a basis from which to derive geomorphological contexts for the two study areas. The wallrocks of Hebes Chasma have been found to have undergone varied degrees of mass wasting, resulting in a widespread, non-uniform spur and gully morphology. Failure has occurred in a significant section of wallrock in Study Area 1 (northern edge of the chasma) and in Study Area 2 (southern edge) the dominant feature is a canyon feature cut back into the plains, for which sapping may be a process of origin. The chasma floor may have been subject to removal of material. Further study is needed to solidify hypotheses. GRASS was found to perform well in the context of extraterrestrial geomorphometry, however, it must be noted that the analyses are based on criteria derived for terrestrial conditions. It has been judged that open source GIS can play an important role in developing the concept of planetary GIS.