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Wnen identifying regions with a rich contents 
chiefly in forming relief elements,there are used 
contact photocopies which are observed stereoscopi- 
cally with a minor stereoscope. 
Laboratory topographic interpretation is carried 
out in two variants: 
1. The first one is applied in forest regions 
with forest height over 4 metres and with dense forest 
massifs, photographed in full leaf. Stereocartography 
in such regions is uncertain and it is necessary that 
& mensural or tachimetric check of the relief should 
be performed after the stereoplotting. Laboratory in- 
terpretation is carried out at the time of stereoplot- 
ting, while field deciphering-at the mensural or tacho- 
metric filling in. This variant of laboratory deciphe- 
ring finds quite a limited application. 
The essence of the second variant is the use of 
standards. There are selected characteristic districts 
which contain all objects that have to be interpreted. 
A thorough topographic interpretation of these dist- 
ricts is carried out and they serve as standards to 
the laboratory interpretation which is made later. 
The fundamental instruments used in laboratory 
interpretation is the interpretoscope "Zeiss". 
Laboratory interpretation is formed, as a field 
photoscheme at an appriximate scale for which it is 
designed. It cannot completly replace the field inter- 
pretation, but there is a tendency for it to take 80 per- 
cent of the total volume of interpretation. 
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