Conclusions 
1. Among the parameters relating to spectral signatures of ob- 
jects are those relating to the state of the atmosphere at the 
time when imagery is taken. Another parameter is the course 
of climate within any specific year. These two factors will 
affect critically the visibility of geological lineations on 
LANDSAT imagery. 
2. A critical assessment of data smoothing and enhancement 
methods used in treating LANDSAT imagery must therefore be made. 
There is a strong possibility that with smoothing and enhance- 
ment algorithms some types of signatures — which here are termed 
"temporal spectral signatures — may be suppressed. (ROHDE, LO, 
POHL 1978; ULBRICHT, HOPPE 1977) This would eliminate features 
which can be interpreted on LANDSAT imagery by conventional 
methods and illustrated on land-use maps (NIEMZ 1977) and geo- 
logical maps of tectonic structures (MERTHES 1976; OLUIC 1975). 
2. A requirement for exact photo-interpretation of LANDSAT imagery 
is, along with other materials, the use of all available photo- 
graphy covering the research area, i.e. conventional aerial 
photography and small-scale meteorological satellite imagery, 
such as NOAA VHRR. (= National Oceanic and Atmospheric Adminis- 
tration satellite, Very High Resolution Radiometer imagery.) 
This has a ground resolution of approximately 1 km, in visible 
(0.6 - 0.7 um) and thermal infra-red (10 - 12 um) bands and a 
repetition rate of 12 hours. 
N.B. My thanks are due to the following for their assistance: 
Dr. Richard Mühlfeld, Bundesanstalt für Geowissenschaften 
und Rohstoffe, Hannover for providing the LANDSAT imagery; 
Prof. Heinz Kaminski, Sternwarte Bochum for providing the 
NOAA VHRR imagery; and Mr. Helmut Schüttemeier, Institut 
für Weltraumforschung, Bochum for producing slides and 
prints to illustrate the paper.