Spectral signature selection for mapping unvegetated soils

Abstract

Airborne multispectral scanner data covering the wavelength interval from 0.40–2.60 μm were collected at an altitude of 1000 m above the terrain in southeastern Pennsylvania. Uniform training areas were selected within three sites from this flightline. These training areas were field mapped as Berks, Duffield and Penn soils. Soil samples were collected from each site and a procedure developed to allow assignment of scan line and element number from the multispectral scanner data to each sampling location. These soil samples were analyzed on a Beckman DK-2A Spectrophotometer and laboratory spectral signatures derived. After correcting for solar radiation and atmospheric attenuation, these laboratory signatures were compared to the spectral signatures derived from these same soils using multispectral scanner data. Both signatures were used in supervised and unsupervised classification routines. Computer-generated maps using the laboratory and multispectral scanner derived signatures resulted in maps that were similar to maps resulting from field surveys. Approximately 90% agreement was obtained between classification maps produced using multispectral scanner derived signatures and laboratory derived signatures.