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Brail, Breuer, Henning, Hohmuth, Priimm, Stamm 
If a software specialized for aerial orthoimage production only (i.e. Phodis) 
is used for terrestrial applications it must be assured that the ortho-image 
projection plane is defined by the X and Y axes of a local coordinate 
system. Otherwise it would be impossible to get a result. Other software 
takes into account the peculiarities of terrestrial photogrammetry. With 
Pictran 32 Bit (Release 3 - Version 3.0.6.1) it was possible to generate 
ortho-images of the facades. Pictran defines the projection plane via three 
points in space. Three points on the facade can be used to define the plane 
for orthoimage processing. The algorithm takes into account a digital 
surface model which is extracted from the overlapping images and stored 
in a triangular irregular network (TIN) structure [Stamm 2001]. 
Figure 3 shows as an example the orthoimage map of the eastern facade of 
the tower-tomb of Elahbel. Note the areas without image information. They 
appear white here. These areas were not visible for the camera from the 
point of image capture. To avoid this, multiple images taken from different 
locations can be used and mosaicked. 
4. VISUALIZATION 
Once threedimensional data is available as a result of photogrammetric 
restitution it can be visualized in an appropriate manner. The traditional 
way is the compilation of facade maps as described above. More 
sophisticated is the creation of orthoimages. In addition to that, modern 
visualization methods allow the construction of digital object models. A 
virtual reality model can be formed by mapping the orthoimages onto the 
digital object model. This requires suitable methods for data modeling and 
rendering. 
In this project, VRML (“Virtual Reality Modeling Language”) has been 
used for this purpose. Main reason for the choice of VRML for the 
representation of the digital object model was the independence of this 
language from computer platforms, whereas “JavaApplets” for instance, 
require a corresponding browser plugin, that has to be installed to view 3D 
scenes. An additional argument for choosing VRML was that it is an open 
and well documented standard, that possesses a big potential especially for 
a possible connection of the photogrammetric restitution process with the 
automatic generation of 3D-objects. 
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Figure 3: Ortho-image map 
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