Tables 1 and 2 show the output of the two programmes for the areas shown in the
rightlook image of figs. 3 and 4.
From table 2 it is clear that shadowed steep slopes in this image are, for the
greatest part, not visible as there is a near coincidence of the areas in shadow
and the areas not visible. The flight parameters are shown in the caption.
Another example is shown in figure 5, representing a subscene from a stereopair
of the Antalya area, Turkey. They are best viewed with south pointing upward so
that the shadows (sun azimuth = 126.6° and 153.6° respectively,) fall towards
the observer.
The subscene shows a strongly karstified limestone area. There is a strong
structural domination, manifest in important lineaments often responding to
fault scarps. It is evident, that many of the steep slopes are not visible in
the westlook image. This, in consequence, has a more monotonous appearance in
the image, not revealing its very rugged topography.
Tables 3 and 4 list the outcome of the analysis of slope shadow and visibility
for the rightlook image of this stereopair.
REFERENCES:
Gorte, B. and Nossin, J.J.(1990).
Programmes to determine slope visibility and shadow in sidelook SPOT imagery.
ITC Journal (in preparation).
Nossin, J.J., Sesoren A. and Hakim I. (1988).
Karst and Submarine Freshwater Discharge in the Antalya Area, Southern Turkey.
In: SPOT-1 , Image Utilization, Assessment, Results.
CNES- Cepadues Editions, Toulouse, France, p. 719 - 731.
Nossin, J.J. (1989). Spot-stereo interpretation in karst terrain, southern
Turkey; ITC Journal 1989-2: 79- 91.
Nossin, J.J., (1990). Slope visibility and shadows in side-look SPOT imagery.
Photogramm. & Remote Sensing (in preparation).
Sesoren, A., (1985). Potential of remote sensing use in a karstic area, Antalya
region in the south of Turkey. Proc. Symp. Karst Water Res., Ankara-Antalya,
IAHS Publ. No 161, p. 271-277.
SPOT HANDBOOK,(1986): Guide des Utilisateurs de Donnees SPOT; CNES et SP0T-
Image, Toulouse.
CAPTIONS
Fig. 1
The general case: slope exposed in a direction different from sun azimuth and
look direction which are also mutually different.
Fig. 2
The iglo with invisible and shadow zones.
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