The DTM is used in close connection with another model 
that describes the sub base of the street. The DEM and the 
soil type model are also parts of this model. The sub base 
model also includes information about the subsoil explo- 
ration points, boundaries, detailed plans, pipelines, 
buildings and special features. 
The subsoil exploration points contain information about 
ground level, storm water level, borring type, class, date 
of borring, borring ending subject and results of the 
exploration. 
when all this is verified it will be possible e.g. to draw 
cross sections showing all local soil type surfaces, 
borring diagrams, underground pipelines, boundaries, 
buildings and borders of the steet area in the detailed 
plan. 
REFERENCES 
/1/ MeCullagh, M.J., Ross, C.G.: Delaunay Triangulation 
of a Random Data Set for Isarithmio 
Mapping. 
The Cartographic Journal, Vol. "17, 
No. 2 (1980), pp. 93 - 99. 
/2/ Kunnallishallinnon atk-neuvottelukunta (KATKO): 
Katu-atk projektin systeemikirja 8: 
Maastotieto järjestelmä (1985). 
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