Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a multi-spectral imaging radiometer with 60 km imaging swath, 15-90 m spatial resolutions, and 14 spectral bands total in the visible and near-infrared (VNIR), short-wave-infrared (SWIR), and thermal infrared (TIR) regions. Wide spectral coverage and relatively high spatial resolution of ASTER will enable us to discriminate a variety of surface materials while reducing the mixed pixel problems. For instance, the SWIR bands are targeting characteristic absorption features of phyllosilicate and carbonate minerals for the purpose of lithologic mapping. Emissivity patterns derived from the TIR bands will be useful to characterize silicate rocks that are the most abundant rock type on the earth. Data from the VNIR bands with high spatial resolution will be helpful not only to assess iron oxide minerals and vegetation, but also to perform photogeologic interpretation of geologic structures and lithologic mapping based upon topographic textures. The ASTER Science Team plans to provide a spectral data base, which will be used as reference data for surface mapping. There are three types of data categories; global data sets, regional data sets, and local data sets. Since operation of the ASTER instrument will be affected by various constraints such as duty cycle and pointing frequencies, it is necessary to optimize the operation scenario for efficient data acquisition. The Geology Working Group of the ASTER Science Team is currently preparing a global prioritization map that will be used for generation of the global mapping scenario.