Full text: New perspectives to save cultural heritage

Cl PA 2003 XIX 11 ' International Symposium, 30 September- 04 October, 2003, Antalya, Turkey 
352 
4. Photogrammetric Analyses 
In order to fulfil the demands of high accuracy the 
stereoscopic models were processed at an analytical plotter 
DSR-11 (Leica). In model orientation an accuracy of approx. 
cr=±5mm could be obtained. The main contour lines and 
ornaments were acquired, separated into original and newly 
supplemented parts. Particularly coffered ceilings, flutes of 
the columns, joints of the brickwork and cracks of the 
building were registered. 
The data were structured in different layers of a CAD system, 
e.g. into architectural elements like base frame, projecting 
columnar orders, ceilings, columns including capitals, 
architraves etc., as well as into different depth layers. This 
structure was defined in collaboration with restoration 
experts before starting data acquisition. Therefore, a great 
variety of different combinations may be created, e.g. ground 
data with or without coffered ceilings, or a front view of the 
building without columns. In principle all data were acquired 
digitally in 3D. Nevertheless additional analogous plans in 
2D were requested by the restorers in order to draw manually 
different building damages into these plans while viewing 
directly at the respective building details. For this 2 ground 
plans and 2 upright projections of the ceilings of the lower 
and upper storey resp. were derived from the 3D data, 2 front 
views with and without columns, solely columns and 
architraves including gables, 2 lateral views and 11 vertical 
cross sections. Figure 3 shows the photogrammetric result in 
terms of a front view of the whole market gate including 
columns (in this case without flutes) and brickwork of the 
back plane. The outer thick line is the contour line of the 
exhibition room. Different grey values represent different 
depths of the architectural elements (black: front level, dark 
grey: middle level, light grey: back plane level). An upright 
projection of the coffered ceiling of the lower storey is 
illustrated in Figure 4. All main contour lines of the coffered 
ceiling are acquired but not every ornament detail like 
rosettes, festons or leaf mouldings. As an example Figure 5 
demonstrates one of the vertical cross sections. It contains the 
two-storeyed projecting columnar order on the left side 
(compare Figure 2). 
5. Completion of photogrammetric 
results and damage mapping 
In a next step a revision and completion of the 
photogrammetric results has to be done by architects and 
restoration experts due to few missing parts which could not 
be captured by photogrammetry and details of ornaments 
which had been excluded a priori, e.g. small parts of the 
backside of the columns or the ornaments on the architrave. 
In Figure 6 the original photogrammetric data and the 
completion by the architects can be compared. In this case 
ornaments on pediment and entablature, the capitals of the 
columns and a part of the roof construction have been added. 
Subsequently a mapping of the existing damages based on 
the photogrammetric results can be elaborated by the 
restorers. It contains a specification of the material, state of 
preservation and comments about construction details (Figure 
7). This information leads to the definition of necessary 
conservation activities (Maischberger, 2003). 
Additionally an expert’s report concerning the statics of the 
Market Gate of Miletus will be given in terms of possible 
damages and negative influences caused by the planned 
construction activities. At this moment it is not decided if the 
whole market gate has to be deconstructed and newly 
reconstructed after the rearrangement of the museums’ island 
in Berlin. 
Figure 3. Photogrammetric plan of a front view of the whole market gate (thick line: contour of exhibition room)
	        
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