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PHOTOGRAMMETRIC RECORDING AND EVALUATION OF THE MARKET GATE
OF MILETUS FOR ARCHITECTURAL HERITAGE CONSERVATION
T. Vôgtle a , K. Ringle a , M. Nutto a , H.-P. Bahr a , M. Pfanner b , F. Zens b , M. Maischberger b
“Institute for Photogrammetry and Remote Sensing, University of Karlsruhe, Englerstr. 7, 76128 Karlsruhe
b ARGE Pfanner, Dircksenstr. 46, 10178 Berlin
Commission V, WG 5
KEY WORDS: Photogrammetry, Close Range, Data Acquisition, Cultural Heritage, Architectural Heritage Conservation,
Archaeology, Damage Mapping, CAD, Pergamon Museum, Market Gate of Miletus
ABSTRACT:
The famous Market Gate of Miletus was transported to the Pergamon Museum (Berlin, Germany) in 1907/08 and rebuilt there in
1928/29. Meanwhile the historical Market Gate shows some damages, and the building itself has to be restored. Therefore, a
documentation of the status of this architectural and archaeological heritage is necessary as a basis for damage mapping and
subsequent restoration activities. Due to the complex architectural structure and the variety of ornaments on the Market Gate of
Miletus a photogrammetric approach was selected.
During an acquisition campaign of 2 weeks the Market Gate was covered by more than 100 stereoscopic models. A high accuracy of
o=±5mm was required for object points and lines. Therefore, more than 200 control points were measured at an accuracy of
cr= ± 3mm.
The results of stereoscopic analysis are 3D data of main contour lines, ornaments and the joints of the brickwork, structured in
different layers. Special vertical and horizontal cross sections can be derived from these 3D data. Some representative examples for
contour mappings, upright projections and transformations will be presented in this paper.
1. Introduction
The Pergamon Museum and its neighbouring museums have
to be restored in the next few years. Before starting these
activities a complete documentation of the status and a report
of the static of all exhibits is necessary. One of these is the
famous Market Gate of Miletus which was rebuilt inside the
Pergamon Museum in 1930. Due to the complex architectural
structure and the considerable dimensions - the market gate
has a length of approx. 30m and a height of approx. 16 m-
stereo photogrammetry was favoured for data acquisition
because it has proved to be suitable in similar applications
(e.g. Nutto, Ringle, 2001). The demands concerning accuracy
had been defined by the restoration experts (archaeologists,
stress analysts etc.) quite restrictive to cr=±5mm for points
and lines in object domain. Besides mapping of damages it
should be possible to rebuild - if necessary - single parts of
the gate based on the produced plans.
2. History of the Market Gate
The monumental Market Gate of Miletus was built between
c. 120 and 130 AD in the time of the roman emperor Hadrian.
This manifold decorated two-storeyed building has three
doorways and was the entrance to the southern market of
Miletus in Asia Minor (Figure 1). It was modified several
times during the centuries, e.g. in the 6 th century D.C., before
it was destroyed in the 11 th century by an earthquake. Parts of
the market gate were rediscovered in 1903 during the
archaeological excavations in Miletus by Th. Wiegand and H.
Knackfuss (Knackfuss, 1924). After the acquisition the
discovered parts of the market gate had been transported
1908 to Berlin by ship. For the first years they were stored in
the storerooms of the museum and the gate was rebuilt in
1928/29 inside the new Pergamon Museum in Berlin
including integrations in modern materials replacing the
destroyed parts. For static purposes a construction of iron
girders was integrated in the gate and fixed to the wall.
3. Photogrammetric Data Acquisition
For data acquisition two campaigns - each of 4 days - were
organised. Because of the specific structure of the market
gate and spatial limitations inside the exhibition room (Figure
1) different photogrammetric cameras had been used. The
front parts of the gate which are oriented towards the
exhibition room were acquired by a UMK 1318 (Zeiss Jena)
because suitable camera distances of approx. 8 m could be
realised (Figure 2). Nevertheless two models had to be taken
in the case of longitudinal tilt because of a ground mosaic in
the centre of the room. Images of interior parts of the gate,
e.g. for the extraction of vertical cross sections, upright
projections and special details, were captured by stereoscopic
photogrammetric cameras SMK 120 / SMK 40 (Zeiss
Oberkochen).
In total more than 100 stereoscopic models were necessary to
cover this complex building. For orientation puiposes more
than 200 measurement targets were fixed to the market gate
as control points and measured geodetically with an accuracy
of approx. CT=±3mm. The images of the upper part of the
market gate had to be taken from a mobile scaffold tower.
Due to the inevitable low- and high-frequency movements of
the scaffold tower (measuring 12m of height) short shutter
times were necessary which was a problem considering the
poor lighting conditions inside the exhibition room.
