Seien- 
leidel- 
ETE 
ute. 0f 
Skopje. 
logy. 
Data on 
»slavia) 
Bs. 
1L and 
1 cen- 
1/2, 
term 
tekto- 
— 
SOIL AND SAND MAPPING USING REMOTE SENSING DATA 
by 
FAROUK EL-BAZ 
National Ain and Space Museum 
Smithsonian Institution 
Washington, 0C, 20560 USA 
The spectral signatures of desert surfaces are easily distinguishable 
in remote sensing data.  Landsat data, for example, clearly show differences 
in the reflectance properties of limestone rock, clayey playa deposits, and 
 dune accunulacions of quartz sand. Parts of the Western Desert of Egypt were 
mapped in this way using Landsat images coupled with field checks. In some 
cases, however, a thin mantle of one-grain thick deposits may mask the nature 
of the soil below. Furthermore, clay-rich desert varnish on limestone or sand- 
stone may give the spectral signature of clay deposits. Such distinctions 
must be made based on field observations. An experiment was recently conducted 
in conjunction with the second flight of the Space Shuttle Columbia. Samples 
were collected from exposed rock rubbl&, soil and sand in the Kharga Oasis in 
the Western Desert of Egypt. Mylar markers were placed on the desert surface to 
identify the sampling sites in remotely-sensed data for correlation. Spectral 
characteristics of these vegetation-free surfaces are correlated with data from 
the Shuttle Multispectral Infrared Radiometer (SMIRR) and multispectral data from 
Landsat. 
575