index 
lng 
ES, 
F the 
od to 
oed 
ke vy: 
U's 
sens. 
lex 
  
7. CONCLUDING REMARKS 
The algorithm proposed was implemented in FORTRAN 4. It runs as part of the 
program system SCOP (Stuttgart Contour Program). It may be used also as stand 
alone program, provided that the DTM is organized in raster form. A sequential 
DTM may be converted to random format, using a special conversion program. 
The SCOP-DTM contains some other valuable information too - as breaklines and 
borderlines. The next step in further development of the algorithm proposed, 
will be the inclusion of these informations. The concept of screen elements 
changing the horizon will be suitable too. The changing density of lines might 
cause difficulties for graphical presentation. 
It should be noted, that the algorithm works very efficient, since each com- 
puting unit of the DTM needs to be read only once at the worst. So it is best 
suited for quality control during the process of DTM-generation. 
It can be run interactively too, so supporting the design phase in road- 
building. 
APPENDIX 
The mathematical tools used: 
perspective transformation: 
Cx x = WAREN xx 
X inner- projection center 
orientation object point 
rotational matrix 
image- point scale 
point 
normalized image coordinates (x, y): 
x X-X 
- - "m o 
vl rz ilA Y zit, 
1 z-7 
O 
user's image coordinates (x, y):