‘The whole area was divided into zones, characterized by 
different land covers. For the fragment covered with short 
grass, using 224 points the following accuracies were 
abtained: 
s, =+0.11 m May = 0.18 m 
Por agricultural land cover, using 386 points the correS- 
ponding accuracies were as follows: 
9, =+0,13 m mg, 0.21 m 
Por terrain influenced by intensive sulphur exploitation 
comprising numerous roads, ditches and pipe-lines, the 
following magnitudes were abtained for 440 points: 
s,=+0.19 m map = 0.23 m 
It can be concluded from the above data, that vegetation 
cover has only slight influence on magnitude of errors, 
despite of unfovourable vegetative stage /aerial photo- 
graphy were taken in June/, while greater influence appe- 
ars due to small artificial terrain forms. 
4. DIGITAL MODEL APPLICATIONS 
4.1 Determination of height deformations for mining 
terrain surfaces 
Described above digital terrain model was utilized for 
periodical registration of terrain surface changes on the 
area of sUlphur mine. At each cycle the digital model for- 
med in the same way was obtained, with the same X,Y coordi- 
nates for sqare grid corners. Determination of height 
differences in succeeding periods was done through subtrac- 
tion of corresponding elemets of tables, comprising point 
heights of suitable DTM's. It was performed using computer. 
The output results were given in the same form as in DTE, 
It gave possibility to make quickly for base map overlay 
with height differences, including isolines of height de- 
formations of terrain surface. 
Mean error of height differences was estimated as equal to 
mean error from 711, multipled 2, omitting systematic error, 
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