The thematic mapper (TM), and advanced sensor on board Landsats 4 and 5, was designed to alleviate problems that limit applications of multi-spectral scanner (MSS) data acquired by previous satellites. This paper presents the results of studies in Texas and Illinois that demonstrate the advantages of TM data over MSS data in standard photogeologic work.

The TM and MSS both provided the synoptic, small-scale imagery essential for mapping regional geologic trends; however, the increased resolution of the TM made it possible to enlarge the imagery to a scale of 1:48,000 (and larger with high-quality bands) allowing both regional and detailed studies from the same data. Analysis of large-scale TM imagery resulted in recognition of many surface anomalies that were not visible on MSS data and more accurate delineation of those that were. The TM thermal infrared band proved particularly useful in detection of faults, and in one locality showed a thermal anomaly over a linear producing sand.

In addition to the advantages of new levels of anomaly discrimination and greater probability of successful prediction of structures, the TM has operational advantages, such as ready transfer to base maps because of evident small townsites, secondary roads, and first order drainage. TM imagery unquestionably extends the scope and effectiveness with which Landsat can be used for hydrocarbon exploration.

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