Hyperspectral Analysis — Edwards Air Force Base
Airborne hyperspectral data were acquired over approximately 300 square miles of Edwards Air Force Base. Along each of the 190 flight lines, reflected sunlight spanning visible to near-IR wavelengths (VNIR) were collected into 128 separate grayscale images (“bands”) with a spatial resolution of 1 meter. The hyperspectral collection was delivered in different formats, ensuring that both basic research and operational mapping programs can be supported. One hundred ground spectra (VNIR), photographs, field observations, and GPS of vegetation, soil, and reference surfaces were collected between 31 March and 23 April. The ground spectral library and photographs were integrated into a GIS to support mapping of the airborne data. The spectral quality of airborne pixels compares favorably with spectra collected on the ground at the same location.
An Excel spreadsheet was built by Tetra Tech that combined the ground spectra documentation with GPS locations, ground photograph IDs, and field observations. This spreadsheet was converted to an ESRI ArcGIS shapefile for display in the GIS. Hyperlinks were created between the ground spectra sites, ground photographs, and graphics of the spectral signatures as displayed in ENVI. A GIS user can click on a hyperlink point displayed on a GIS image or map and see photographs of the vegetation being measured with the portable ASD spectrometer, a graphic of the spectral signature, and field notes. This GIS integration of the ground spectral library, photographs, and field notes support efficient mapping of the airborne data. Tetra Tech integrated the spectral data with EAFB UltraCamX orthos and the base LiDAR DEM to provide spatial reference. To improve understanding of the environment, derived maps included spectral data integrated with color-coded & shaded LiDAR and small-scale soil maps in the GIS.