As a result of the interpolation the DTM grid is represented 
by an image where line and sample of a pixel define the 
planimetry in the map projection. The height above the re- 
ference body is coded as a grey value with a depth of 16 
bits. With this type of integer data it is possible to 
describe 65,536 different heights. Considering that a 
height accuracy of 1 meter or better cannot be expected 
due to image resolution and the accuracy of the recorded 
orientation parameters, each grey value represents a 
fixed height in steps of 1 meter. Thus the 16bit-depth of 
the data includes the entire range of possible heights on 
Mars with its tremendous height differences rising up to 
30 kilometers. 
  
Figure 2: Visualization of a DTM 
as 8 bit grey value coded image 
For the visualization of the resulting grey-level coded 
height image it is necessary to compress the 16 bit grey 
values to 8 bit grey values (Fig.2). Various other types of 
visualization techniques of DTM information will also be 
developed under the software and hardware guidelines of 
the Mars96 Mission, e.g. contour lines (Fig.4), wire frames 
or perspective views (Fig.3) of a DTM probably overlayed 
with image information. 
AF IR 
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Figure 3: Perspective view 
derived from the DTM shown in Fig.2 
896 
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Figure 4: Contour map 
derived from the DTM shown in Fig.2 
5. CONCLUSIONS 
The developed techniques for the generation of Digital 
Terrain Models are, together with components for image 
matching, orthoimage and image mosaic generation and 
automated cartographic software, essential parts of an 
overall processing line for the production of Topographic 
Image Maps during the Mars 96 Mission (Albertz et al 
1996). Beside this, the developed approach for DTM 
generation can be applied to any modeling of heights 
where a high density of object points exist. The quality of 
the products always depend on the accuracy of the 
geometrical processing. 
6. REFERENCES 
Albertz, J., Ebner, H., Heipke, C., Neukum, G., Scholten, 
F., 1992. The Camera Experiments HRSC and WAOSS on 
the Mars 94 Mission. In: International Archives of Pho- 
togrammetry and Remote Sensing, Washington D.C., 
USA, Vol. XXIX, Part B1, pp. 130-137. 
  
  
   
  
  
  
  
  
  
  
  
    
    
   
     
   
   
   
   
   
  
    
    
   
   
  
   
   
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