depths as great as 22 m have been successfully imaged in the Bahamas 
areas and bathymetric contours determined with errors of 10 percent 
or less. The difficulty of charting in these shallow areas by con- 
ventional means and the growing economic significance of these areas 
testify to the importance of this capability. 
In an effort to pinpoint locations on Landsat images, experiments 
were undertaken in which mirrors, approximately 1 m in diameter, were 
successfully located in the image and on the digital data. Thus 
precise location of the mirror was possible within one pixel (59 m x 
79 m) (Evans, 1974) (Colvocoresses, 1975). 
Geologically, the data are demonstrating that: 
1) There are large structural features on the surface of the 
Earth that are visible only in the uniform, synoptic view available 
from Landsat and that some of these features are significant with 
respect to the localization of mineral and energy resources and to the 
location of seismic activity; 
2) some geologic and geohydrologic features are only intermittently 
visible depending on angle of illumination, or snow, water, or vegetation 
distributions; : 
3) multispectral data, properly processed, are useful in mapping 
the distributions of some rock types, geochemical anomalies, and altera- 
tion products; by applying different computer handling techniques, 
favorable results have been obtained in well-exposed terrains and the 
possibility of relating vegetation anomalies to the occurrence of miner- 
al deposits of various types is being explored. Initial results have 
provided evidence that certain types of anomalies can be recognized in 
tropical and temperate climates; 
4) the understanding of some dynamic phenomena, such as surface 
water availability, surging glaciers, snow lines in mountain areas, and 
sedimentation (Reimnitz and Carlson, 1975) is improved if Landsat imagery 
is studied in a "time-lapse" mode; 
5) utilizing the Data Collection System (DCS) capability of Landsat 
signals are being relayed from seismic event counters and tiltmeters 
emplaced on 15 volcanoes in Central and North America and from numerous 
hydrologic stations. 
9 
W.D. Carter (Fischer and others, in press) is continuing 
interpretation of lineaments and curvilineations as seen on Landsat 
mosaics of the United States produced by the Department of Agriculture 
in cooperation with the National Aeronautics and Space Administration 
(NASA). Carter's initial interpretation is being repeated independently 
by a number of scientists in the USGS to build a level of confidence in 
   
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