ANALYSIS OF A MULTISENSOR IMAGE DATA SET 
OF SOUTH SAN RAFAEL SWELL, UTAH 
by 
D.L. EVANS 
Jet Propulsion Laboratory 
MS 185-701 4800 Oak Grove Drive 
Pasadena, CA 91109, USA 
ABSTRACT 
A Shuttle Imaging Radar (SIR-A) image of the southern portion of the San 
Rafael Swell In Utah has been digitized and registered to coregistered 
Landsat, Seasat, and HCMM thermal inertia images. The addition of the SIR-A 
image to the registered data set Improves rock type discrimination In both 
qualitative and quantitative analyses. Sedimentary units can be separated in 
a combined SIR-A/Seasat image that cannot be seen in either image alone. 
Discriminant Analyses show that the classification accuracy is improved with 
addition of the SIR-A image to Landsat Images. Classification accuracy is 
further improved when texture information from the Seasat and SIR-A images is 
incl uded. 
INTRODUCT ION 
The San Rafael Swell is a large (80x35 km) doubly plunging anticline in 
Eastern Utah (USA). It Is made up of continental and marine sediments that 
were uplifted in the Cretaceous (75 to 50 million years ago). There are 
several economically Important geologic units in the region because the 
combination of Iithologic and structural features result in transport of 
mineralizing fluids and localization of ore bodies (e.g. Hawley, et al. 
1968). ^A geologic sketch map is shown as Figure 1. 
The synoptic view provided by orbiting sensors is particularly valuable 
to geologists in this type of terrain because geologic units of interest can 
be traced over large areas. Several orbiting sensors have obtained images of 
this area in various portions of the electromagnetic spectrum. Visible and 
near Infrared images were obtained by the Landsat Multispectral Scanner (MSS), 
thermal Infrared Images were obtained by the Heat Capacity Mapping Mission 
(HCMM) satellite, and radar Images were obtained by both the SIR-A and Seasat 
synthetic aperture radars (SARs). The resulting data set provides a unique 
opportunity to compare radar Images obtained with differing incidence angles, 
as well as combinations of radar Images with images obtained In other portions 
of the spectrum, for geologic remote sensing. 
EXPERIMENTAL PROCEDURES 
A portion of the SIR-A image of the San Rafael Swell was digitized and 
registered to the coregistered Landsat and Seasat Images described in Blom et 
al.(1981) and Blom and Daily (1982), and a thermal inertia image described in 
Kahle, et al. (1981). The SIR-A swath covering the area was scanned with a 
Perkin Elmer microdensitometer PDS with a 50 micrometer spacing, and digitized 
to 256 gray levels. The digitized Image was then registered to the previously 
coregistered data by finding common tie points in the images, and rotating and 
Sizing the SIR-A Image to fit the others. Figure 2 is a SIR-A image of the 
southern portion of the San Rafael Swell. The area of overlap between the 
SIR-A image and the Landsat/Seasat/HCMM data set is outlined on the figure. 
Figure 5 Is a location map of the SIR-A pass. 
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