Photogrammetric Methods for Documentation of Historic Monuments ... 
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2. THE CHURCH OF THE MONASTERY IN SALEM 
A main object of work in the last 12 years has been the church of the monastery in Salem, situated north of Lake Constance. The 
monastery’s church, originally built in gothic style with several rebuildings in the baroque period and later, is to be renovated. 
Before this, the stone facades and the roof truss have been documented carefully and in detail, using different methods. 
The first photogrammetric task in Salem was to evaluate the damage to the stone facades in 1988. A badly damaged sector was 
chosen to demonstrate the necessity of restoration. It was documented by stereo images and by analytical restitution - at this time 
without secondary data processing. To evaluate the damage, a legend was developed to express both the depth and the nature of the 
damage. After detailed examination of areas of the building in situ, the legend was then applied to the drawing by stereoscopy 
(Grassegger/Eckstein 1990). Secondary examinations were done with time-lapsed stereo-images in order to measure the rate of 
decay of the stone surfaces (Eckstein 1992). 
In 1992, the complete facades were photographed, the restitution has been done corresponding to the restoration work till 2001 
(Fig. 5). 
1981, 
linear 
Fig. 5: The church of the monastery in Salem. Section of the west facade. Detailed photogrammetric stereorestitution, subdivided in 
several layers. Especially the outlines of the stones are separated and closed as a polygon in order to indicate the restorer’s findings 
in a CAD-system. 
In the meantime, the restitution data could processed sensibly in a CAD-system. 
In a pilot study concerning the Frauenkirche in Esslingen, which was included in the BMFT-research programme "Preservation of 
Historical Monuments", the Landesdenkmalamt Baden-Württemberg investigated how different damage types and their causes can 
be detected by CAD-based methods. To do this, the photogrammetric restitution has to be subdivided into several layers; especially 
the outlines of each stone have to be separated and to be closed as a polygon. The findings, ascertained by the restorers, like type of 
damage, depth of damage, type of stone and mortar, age of stone and former restorations, are stored in a data base and combined 
with the CAD-data, according to a geoinformation system (Eckstein/Dendler 1994-96, Eckstein 1999). Based on these 
investigations, the system has been taken over and developed by several restorers, not only in Salem but also by other projects in 
Baden-Württemberg (Schäfer 2001). 
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