Comparison of airborne and satellite hyperspectral data for geologic mapping

Airborne hyperspectral data have been available to researchers since the early 1980s and their use for geologic applications is well established. The launch of NASA's EO-1 Hyperion sensor in November 2000 marked the establishment of a test bed for spaceborne hyperspectral capabilities. Hyperion covers the 0.4 to 2.5 mum range with 242 spectral bands at approximately 10nm spectral resolution and 30m spatial resolution. Analytical Imaging and Geophysics (AIG) and CSIRO have been involved in efforts to evaluate, validate, and demonstrate Hyperions's utility for geologic mapping in a variety of sites in the USA and around the world. Initial results over a site at Cuprite, Nevada, with established ground truth and years of airborne hyperspectral data show that Hyperion data from the SWIR spectrometer can be used to produce useful geologic (mineralogic) information. Minerals mapped at Cuprite include kaolinite, alunite, buddingtonite, calcite, muscovite, and hydrothermal silica. Hyperion data collected at other sites under optimum conditions (summer season, bright targets) indicate that Hyperion data meet pre-launch specifications and allow subtle distinctions such as determining the difference between calcite and dolomite and mapping solid solution differences in micas caused by substitution in octahedral molecular sites. Comparison of airborne hyperspectral data (AVIRIS) to the Hyperion data establishes that Hyperion provides similar information content, with the principal limitations being reduced spatial distinctions caused by the 30m spatial resolution and limited mapping of fine spectral detail based on lower signal-to-noise ratios.