Soon after the launch of the initial ERTS satellite in 1972 several facts became evident. (1) The multispectral scanner, which takes data and processes it in digital form, was a powerful new reconnaissance tool added to the geologist's list for evaluating prospective hydrocarbon and mineral producing areas. (2) Based on NASA laboratory and field experiments, if additional spatial resolution (from 80 to 30 m pixels) and additional spectral resolution (more bands in the near infrared and infrared) were added, the tool would be more valuable for the geologist. (3) There were inherent errors in the system affecting both geometric and radiometric accuracy.

During the 10 years following the 1972 initial launch, three more Landsat-type satellites were launched with the latest, Landsat 4, incorporating many of the changes requested by geologists. The new multispectral scanner has seven spectral bands covering portions of the visible, near infrared, and infrared. The ground resolution now is about 30 m (100 ft).

The purpose of this presentation is to introduce some processed images from the Landsat 4 thematic mapper, compare these images in terms of quality and information content to Landsat MSS, and to discuss methods of integrating these data into an exploration program. Methods of calibrating the images as well as methods of combining multiple diverse data sets also will be covered.

Examples of several geologic areas will be shown where multiple types of digital processing provide different types of information of the areas. Methods for extracting lithologic, structural, and vegetation cover information also are covered.

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