formulate the procedure of the data pre- 
paration for the apexes and basic surfa- 
ces construction. 
We have described above the DEM set on 
the regular grid. The similar description 
can be used for digital models in the 
vector presentation, i.e. for the isoli- 
nes maps processing. In this case we deal 
with Z-axis ordering data. The construc- 
tion of the relief sceleton lines frame- 
Work before the raster presentation per- 
mits to make up the DEM satisfying not 
only the topographical accuracy but keep- 
ing the shape and the structure of the 
initial surface. 
The suggested mathematical model can be 
considered as the static one. The surface 
description in the form of the weighted 
graph permits us to construct a mathema- 
tical model of the water masses transfe- 
rence and particle transportation along 
the surface. If we put infiltration ratio 
and external water power on nodes and 
channel capacity on arcs of the graph we 
can build a mathematical model serving 
for the flow modeling and erosion proces- 
ses investigation using simple discrete 
calculation technique. 
REFERENCES 
Antipov,MeVe, and Kireytov,V.R., 1979. 
Relief surface T(W) set construction. Ge- 
ologia i geofizika, 11:90-97 (in Russian) 
Antoshchenko-Olenev,I.V.,and Golda,Ya.V., 
1986. Methodology of the automatization 
of geological interpretation. Sovietskaya 
geologia, 8:7-15 (in Russian). 
Gold&, Ya.V., and others, 1986. Working 
out of methods, algorithms and computer 
software for automatical construction of 
geological interpretations mape Report by 
theme I A.VIII/627 during the period of 
1984-1986, Kazgeofizika, Alma-Ata, state 
register No 26-84-21/31 (in Russian). 
Horton,R.E., 1945. Erosional development 
of streams and their drainage basins: hy- 
drophysical approach in quantitative mor- 
phology. Geol. Soc. America Bull., 
56:1117-1142. 
Kuznetsov,B.M., and others, 1979. The de- 
vice of inputting of coordinates and 
heights of stereo terrain model points 
into ES computer /"Format-130"/. In: Aeri 
al and space automatical data processing 
methods and technical means. Leningrad, 
PP+42-55 (in Russian). 
Strahler,A.N., 1952. Hypsometric (area- 
altitude) analysis of erosional topogra- 
phy. Geol. Soc. America Bull., 
62:1117-1142. 
Shreve,ReLe, 1966. Statistical law of 
Stream numbers. The Journal of Geology, 
(1) 317-370 
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