CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
665
0 2 2 3 5 n
Figure 9. Digital photo of Tower 5 at Ankara Kale before
and after rectification. A rectified greyscale image is inserted
to the AutoCAD file to match the control points and an
outline drawing of the individual stones can be produced by
digitisation. The image can also be printed to scale and stone
outlines traced by hand, preferably on acetate.
The final example chosen to illustrate rectification and 3D
modelling techniques is a study of the Byzantine-Ottoman
castle walls of Ankara. The research is undertaken by Sinan
Suluner as part of his PhD thesis, supervised by Prof. Dr.
Omur Bakirer. The study focused on the towers at the Ankara
Kalesi Zindankapi where recent restoration work has been
carried out under the auspices of the Turkish Ministry of
Culture. The aim was to produce a 3D model of the towers
and rectified photographs of wall faces from which scaled
elevations could be drawn. The graphics and drawings assist
in the analysis and the statistical study of the building
materials that were used and reused during construction in
the Byzantine and later periods.
To collect the necessary data, a GPS survey was conducted
over seven days using a Trimble 4600 LS rented from the
British Institute of Archaeology at Ankara. T his GPS system
utilises a base station and a roving antenna to provide highly
accurate measurements. Approximately 10,500 readings were
taken. A static survey, lasting two days, provided the UTM
WGS 84 coordinates for a selection of fixed points located
during the restoration work. Data processing was done with
the GPSurvey program. Points needed for the rectification
were also collected using the static survey technique while a
kinematic survey provided data for a 3D surface model
constructed using the G1S software Arcview 3.2 and Arcview
8.2.
Where it was not possible to measure points with the GPS,
either because of the inaccessibility of the point or because
the GPS signals were masked, a theodolite was used. Kemal
Giilcen, from the METU Photogrammetry Laboratory,
carried out the theodolite survey, measuring (x,y,z,)
coordinates for all necessary points. AERIAL 5 was used to
rectify the digital photographs (Fig. 9) from which tracings of
individual stones were done.
3. CONCLUSIONS
There are, perhaps, three largely separate but overlapping
areas in which these techniques can be used and developed:
1. Rapid, efficient, accurate and detailed recording,
or documentation, of archaeological and architectural
features. Applications include the recording of standing
structures, such as built defences, and of excavated
remains. It is possible, and indeed desirable, to use these
techniques in emergency situations as well as in routine,
day-to-day, recording.
2. The 3D models permit realistic rendering and
multi-perspective views of monuments in their present
condition and situation. Modelling will also allow
projection of the effects of active restoration and
conservation schemes.
3. The graphic displays of heritage sites and
monuments, as they are at the moment and as they may
once have been, permits world-wide dissemination to a
variety of audiences. This can be achieved by means of
the World Wide Web, publication on CD-Rom or DVD,
or in printed form.
The methods and techniques used for the different studies
were selected so as to provide a comparative study of
different approaches. The potential of Information
Technology and GIS tools in the study of architectural and
urban elements of the historical and the present environment
has been demonstrated. They could equally well be used to
make visual projections of the results of active and intrusive
conservation and restoration programs. It must however be
noted that the increasingly sophisticated software and
hardware are continually stretching both human and financial
resources, and the need to upgrade the hardware or to acquire
new software is difficult to meet.
4. REFERENCES
Baturayoglu, N., Summers G.D., Summers, F., Aydin, N.,
2001. The Survey and Documentation of an Iron Age City in
Central Anatolia: Kerkenes Dag, Proceedings 18 th
International Symposium CIPA 2001, 18-21 September
2001, Potsdam (Germany), pp. 407-414.
Baturayoglu, N., 2001. The Survey and Documentation of
the City Wall and Cappadocia Gate of the Iron Age
Settlement on Kerkenes Dag in Central Anatolia,
Proceedings 18 th International Symposium CIPA 2001, 18-21
September 2001, Potsdam (Germany), pp. 100-107.
For further information on the Kerkenes Project, see:
http://www.metu.edu.tr/home/wwwkerk/index.html
5. ACKNOWLEDGEMENTS
Studies reported here have been conducted by METU staff
and students involved in research undertaken from the
Kerkenes Project Office, Faculty of Architecture. We thank
all those who have been involved in this multi disciplinary
research as well as those who provided technical or financial
support, in particular ESRI, ERDAS, Islem GIS and John
Haigh (AERIAL). METU Faculty of Architecture AFP grants
(1999 to 2001), coordinated by Prof. Dr. Omur Bakirer, have
largely supported the ongoing studies. We also thank Refik
Toksoz and Geoffrey Summers for sharing their expertise.
