156
Statistical differences between the directional
distribution of dikes interpreted from radar and
those interpreted from LFC photos are strongly ef
fected by radar look direction. The classes in a
range of 20° around the radar, look direction are
strongly underrepresented on radar whereas perpendi
cular to it the directions are overrepresented com
pared to the LFC image.
The sun direction azimuth with sun elevation of
49°, seems neither to have much influence on enhan
cement of lineaments on LFC photos perpendicular to
this direction nor on suppression in frequency for
directions parallel with the sun azimuth. The influ
ence of radar penetration does not seem to contribu
te much to the differences observed.
ACKNOWLEDGEMENT
The study is past of the NASA/JPL SIR-B experiment
and carried out in the context of ITC research
project 743401.
As a member of the SIR-B science team, the author
wishes to acknowledge the valuable co-operation of
C. Elachi, principal investigator of the SIR-B pro
ject, and his JPL co-investigators. Because of poor
data collection over the author's own test site, he
was given the opportunity by T. Dixon of JPL to
study the Sudan/Egyptian radar strip and Large
Format Camera photography. N.H.W. Donker of ITC
assisted with the statistical analysis. Drawings
were made by Lutke Schipholt and the manuscript was
typed by Anne van der Linde.
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