In compilation of the geological maps RSM are 
used for solution of following main tasks: 1, 
determination of areal stratified and non-stratified 
objects from peculiarities of their representation 
(hue, texture); 2, determination of linear objects 
(tracing the geological boundaries and faults, 
dikes, individual layers and reference horyzons 
within layers of homogenous composition); 3, 
revealing the petrological composition of 
mapping objects, including areals and zones of 
altered rocks. 
2. INFORMATIVENESS OF RSM 
2.1 Natural factors 
The informative character of RSM is affected by 
two groups of factors, natural and technical. The 
most important natural factor is the state of 
landscape. Therefore obtaining of the potentially 
informative image is associated with selection of 
the optimum season and time for surveying. The 
proper choice provides the most expressive 
representation of main indicators of geological 
objects from RSM. 
2.2 Technical factors 
Main technical factors are resolution of the 
images and their spectral characteristics. 
Resolution. The resolution can be considered 
sufficient if the objects whose minimum 
dimensions correspond to the requirements of 
the scale of the compiling map are revealed from 
RSM. The immediate determination of the 
mapping objects is, however, possible only with 
good conditions of the interpreting. In the 
majority of cases, the mapping objects are 
revealed from a combination of natural indicators 
whose dimensions are an order less than the 
object itself. Therefore, the image resolution 
must provide the revealing of the indicators 
rather than the objects. The necessity of 
providing psycho-physiological comfort of the 
670 
interpreting process which significantly affects its 
efficiency should be also taken into account. This 
comfort can be provided with the image 
resolution of 5 to 10 lines per mm, i.e. 20 to 40m 
in conversion to the resolution in locality. 
Spectral characteristics. |t is advisable to 
consider the requirements for RSM spectral 
characteristics in groups of tasks. 
To distinguish objects according to their tone 
characteristics and to solve  structural-tectonic 
problems, it is necessary to use the materials 
covering the long-wavelength part of the visible 
optical range and the near infrared part of the 
spectrum. It is possible to gain supplementary 
information which mainly permits the problems of 
structural interpreting to be solved when using 
radar images. 
To solve the problems of determination of 
petrological composition of geological bodies it is 
advisable to use the whole of the visible and 
infrared ranges. 
Materials of surveying in the thermal range are 
most effective while revealing some specific 
objects (zones of recent volcanicity, solfataric- 
fumarol activity). 
3. CHOICE OF RMS 
3.1 Rules 
Basic tasks of geological mapping from RSM are 
to be solved following two rules: 1, objects of 
minimum size to be mapped or their indicators 
are to be revealed using RSM; 2, images must 
cover a territory as fully as possible and 
represent the position of the mapped territory in 
general structure of region. This necessitates 
using the materials of higher level of 
generalization (on 3 to 5 times smaller scale than 
basic materials) 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996