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5. RESULTS AND FUTURE ACTIVITIES 
Training of photogrammetric operators is currently going 
on and the first results are encouraging. Even though it 
is a quite different approach from direct contouring they 
are acquainted with, savings in time and accuracy 
improvements are obvious. Some test areas are chosen 
for verification of the developed functions and for getting 
new experiences. Results that can be found in prevous 
reports (Bill, 1986; Mann, 1988) concerning efficiency 
(ime and data quantity) and accuracy of various data 
acquisition strategies are confirmed. 
Instrumental limitations are the only but considerable 
factor that lowers efficiency of the system. As far as the 
software is concerned there are still few things that can 
be done to improve the efficiency of the system. Further 
activities on software developments include: 
e calculation of optimum spacing for initial coverage 
of photo model area by systematic sampling 
(Kraus, 1984); 
e development of other functions for DTM analysis: 
slope calculations, perspective views, etc.; 
e total integration of DTM functions and information 
within MapSoft. 
Further utilization of the developed software and new 
scientific projects will enable determination of the solid 
criteria for optimum high quality DTM modelling. 
6. CONCLUSIONS 
The most important functions for support to DTM data 
acquisition and verification on analogue stereoploters 
are provided within MapSoft software system. Flexibile 
data model, support to various data acquisition 
Starategies and the functions for the data verification 
enable high quality terrain modelling. The same 
functions can be used for the digitization of the existing 
maps also. 
REFERENCES 
References from Journals: 
Akima,H., 1974. A method of bivariate interpolation and 
smooth surface fitting based on local procedures. 
Communications of the ACM, Vol. 17, No.1, pp. 18-20. 
Akima,H., 1978. A Method of Bivariate Interpolation and 
Smooth Surface Fitting for Irregularly Distributed Data 
Points. ACM Transactions on Mathematical Software, 
Vol.4, No.2, pp. 148-159. 
Barnhil,R.E., Farin,G., 1981. C’ Quintic Interpolation Over 
Triangles - Two Explicit Representations. International 
Journal for Numerical Methods in Engineering 17, pp. 
1763-1778. 
LiZ., 1994. A Comparative Stydy of The Accuracy of 
Digital Terrain Models (DTMs) Based on Various Data 
Models. Photogrammetry and Remote Sensing, Vol 49, 
No 1, pp. 2-11. 
McCullagh,M.J., Ross,G.C., 1980. Delaunay Triang- 
ulation of a Random data Set for Isarithmic Mapping. 
The Cartographic Journal, Vol.17, No.2, pp. 93-99. 
Mirante,A., Weingarten,N., 1982. The Radial Sweep 
Algorithm for Constructing Triangulated Irregular 
Networks. IEEE Computer Graphics and Application 2, 
pp. 11-21. 
Sibson, R., 1978. Locally equiangular triangulations. The 
Computer Journal, Vol. 21, No. 3, pp. 243-245 
References from Books: 
Cvijetinovié, Z., 1995. A Conception of the Acquisition 
and Processing of Digital Height Information within the 
State Survey Programme, M.Sc. thesis (in Serbian). 
Faculty of Civil Engineering, Belgrade. 
Fritsch,D., 1991. Raumbezogene Informationssysteme 
und digitale Gelándemodelle. Dissertation, Munich. 
Kraus,K., 1984. Photogrammetrie, Band 2: Theorie und 
Praxis der Auswertesysteme. Ferdinand Dümmlers 
Verlag, Bon. 
Mihajlovié,D., Cvijetinovi¢,Z., 1996. MapSoft ver 3.0 - 
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Belgrade. 
Neureither,M., 1992. Modellierung — geometrisch- 
topologischer Daten zur Beschreibung und Berechnung 
netzartiger und fláchenhafter Strukturen. Dissertation, 
Munich. 
Sekulovic,M., 1984. Finite Element Method, (in Serbian), 
IRO "Gradjevinska knjiga", Belgrade. 
References from Other Literature: 
Bill, R., Steidler,F., 1986. Progressive Sampling Using 
Triangular Intermeshing - An Efficient Photogrammetric 
DTM Data Acquisition Method. In: ISPRS Proceedings of 
the Symposium Rovaniemi, Commision Ill, Vol. 26-3/1, 
pp. 69-78. 
Ebner,H., 1988. Generation, Management and Utilization 
of High Fidelity Digital Terrain Models. In: International 
Archives of Photogrammetry and Remote Sensing 
Kyoto, Japan, Vol 27, Part B11, pp. 556-566. 
Mann,H., 1988. Progressive Sampling. A New Realization 
of a Method for Interactive Data Collection for Digital 
Elevation Models on Analytical Plotters. In: International 
Archives of Photogrammetry and Remote Sensing, 
Kyoto, Japan, Vol 27, Part 10, pp. 310-325. 
Mihajlovió, D., Cvijetinovió, Z., 1992. Digital Cadastral Map 
Using Software System MapSoft. FIG  Intenational 
Conference "Land Reform and Cadastre", Sofia, Bulgaria. 
Reinhardt,W., 1988. On Line Generation and Verification 
of Digital Terrain Models. In: International Archives of 
Photogrammetry and Remote Sensing, Kyoto, Japan, 
Vol 27, Part 11, pp. 546-555. 
Steidler,F., Zumofen,G., Haitzmann,H., 1984. "CIP" a 
Program Package for Interpolation and Plotting of Digital 
Height Models. In: International Archives of 
Photogrammetry and Remote Sensing, Rio de Janeiro, 
Brazil, Vol 25, Part A3b, pp. 1040-1049. 
211 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996