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Eckstein 
Stereo-restitution guarantees high accuracy. Other photogrammetric surveying methods cannot achieve the required accuracy in 
detail if each stone must be precisely recorded. Furthermore, the accuracy is necessary if the buildings have structural deformations 
and damages - only by a spatial analysis the recognition of such damage is possible. In these cases, there is no sense in using image- 
maps. If only parts of the wall - and not each stone - are assessed, and if there will be no structural problems, rectificated images or 
orthophotos can be used. The restorer’s findings can then be drawn in separate layers over the digital images. This is also true for 
cases where only findings to investigate the history of the building are being pointed out (Fig. 6). 
Fig. 6: St. Vitus in Mönchengladbach. Section of the west facade. Image mosaic by digital rectification. The restorer’s findings are 
drawn in separate layers over the images because parts of the wall and not each stone will be assessed. (Rheinisches Amt fur 
Denkmalpflege) 
The roof truss of the church in Salem includes constructions dating to 1300 and rebuildings in the baroque area. Especially the 
original fabric of the medieval roof has an exceptional quality. A lot of historical findings, concerning the working of the wood and 
the building up, had to be documented. Ground plans and transverse sections of each construction system were measured by 
tacheometry and additional manual drawings. Additional transverse sections were copied and redrawn in order to map and to 
describe all findings (Fig. 7). The next step was to map out the different kinds of damage. The documentation was completed by 
photographs (Fig. 8). 
Using the scientific surveys and the damage plans, with regards to the stone facades as well as to the roof truss, a strategy of repair 
and stabilization was developed. The preliminary examinations enabled precise definition of the tasks; accurate estimates regarding 
costs and deadlines were possible. 
For further scientific investigations and presentations, a virtual 3D model of the church was generated. My colleague Marin Dendler 
explains and comments upon this work in these proceedings. Especially he shows the reconstruction of the gothic and baroque 
towers of the church and the roof construction over the choir.