The analysis was carried out by every author separately, 
on an approximate scale of 1:230,000, and the first author 
investigated also the broader area on scale 1:1,000,000. 
The final sketch included only fractures and ring structures 
Shown in all these representetations. This mode was chosen 
in order to investigate personal influence, scale. and 
image quality in the interpretation. The following conclusions 
have been drawn: 
Subjective factor. Same as any other analysis (field, 
photogeologic, office), the analysis of space imagery is not 
deprived of subjectivity. Several sources of subjectivity 
have been noticed in this study: 
- Fractures are often marked by discontinuous traces in the 
relief, and every author -depending on his training, image 
quality and scale- makes his own choice in linking them, 
showing them as short individual fractures, or adopting 
various possible relations in domains of branching. 
- A scanogram normally shows a very wide number of fractures; 
the choice of the ones to be presented or neglected bears 
necessarily the elements of subjective decision. 
- Training of the interpreter controls his capability of 
discerning fractures not clearly sculptured in the relief 
(the scanogram has been analysed also by two young 
interpreters, trained in photogeology but unexperienced; 
their interpretations differed significantly from each other 
and from the interpretation by the present authors). 
The scale controls dimensions of perceptible fractures, 
which is well known in photogeology. Large scale imagery 
(about 1:230,000) is suitable for discovering fractures 
of even km-dimensions; large (Hkm) fractures are not readily 
seen on this scale. Small scale imagery (1:1,000,000) 
makes possible discovering the large, Hkm-fractures, even 
when poorly expressed in relief.