375 
EVALUATION OF A THEATRE BY USING LOW-ALTITUDE AERIAL AND 
TERRESTRIAL PHOTOGRAMMETRY 
T. M. Celikoyan a , M. O. Altan a , G. Kemper b G. Toz a 
a ITU, Division of Photogrammetry, 80626 Maslak Istanbul, Turkey, (mcelikoyan, oaltan, tozg)@itu.edu.tr 
b GGS, Kammererstr.14, 67346 Speyer, Germany, kemper@ggs-speyer.de 
WG5 - Archaeology and Photogrammetry 
KEY WORDS: Archaeology, Three-Dimensional, Visualisation, CAD, Helium-Balloon, Remote Controller 
ABSTRACT: 
This study describes a special application of aerial photogrammetry. A digital camera, mounted under a balloon has been used for 
taking aerial photos. The plan of the antique theatre in Patara had to be mapped out of photogrammetric stereo-models, which have 
been generated from the photos. Taken from the Helium-balloon, the photos view the area from an altitude of 30 to 40 meters. This 
altitude is fine for a suitable ground resolution of 5 cm. Another parameter for the flight altitude was the lift force of the balloon, 
which has a limit to approx. 50 m for this application. Computer CDs have been used as ground control points, which were painted 
with blue colour, so that they wouldn’t reflect for being clearly visible. The entire area was marked by approximately 80 of such 
ground control points. They have been measured by classical terrestrial methods with a Pentax ATS 102 total station. For the facades 
of the theatre, classical terrestrial photogrammetric methods have been used. Some stone comers have been taken as additional 
control points. Their positions have been mapped onto a sketch. 
The evaluation process has been done using Pictran and AutoCAD software. At the end of the study, a detailed layout plan, some 
profiles and plans of all facades has been evaluated. 
In an ongoing study, photogrammetric tests with PhoTopoL-Atlas Software are running with the goal to create an accurate 3d model 
with animations of the theatre. Further on, the data should be stored in GIS application as well to be part of web-based GIS- 
application for tourist affairs and as well as for archaeological reconstruction aims. 
I. INTRODUCTION 
Photogrammetry is a very suitable evaluation technique for 
many complex objects. It is widely used for documentation of 
archaeological heritage. For this purpose, terrestrial images are 
used for a long time, both, for facades and ground plans. Digital 
photogrammetric techniques allow evaluating oblique 
photographs but in most cases this kind of photos make the 
exterior orientation difficult and the evaluation progress much 
longer. This disadvantage appears especially by drawing maps 
of the study areas. 
As well known, aerial images are most suitable database for 
evaluating and mapping objects. But the high-cost of aircraft 
campaigns force the scientists and photogrametrists to think 
about cheaper solutions especially for smaller areas. These 
solutions are: (Leloglu et all.) 
Kite 
Balloon 
Remote controlled model helicopter 
Remote controlled model aircraft 
Some of these solutions have already tested for remote sensing, 
archaeological documentation, change detection etc. A 28 mm 
camera hanged up to the balloon has been used for change 
detection purposes from 100-200 m in height (Miyamoto et al.) 
Another low-altitude aerial photogrammetric application was 
done about archaeological documentation with a 35mm camera 
mounted under a balloon from 31m height (Karras et al.). 
2. IMAGE ACQUISITON AND PLATFORM 
2.1 Study Area 
Patara is an ancient city placed in the southern part of Turkey, 
situated at the Mediterranean coast near Kalkan, between 
Fethiye and Antalya. Patara, founded about 500 BC, was the 
major port of the Lycian empire, located at the mouth of the 
Xanthos River. Patara was enlarged under Alexander the great 
in the year 333 BC. Around the year 300, St. Nicholas was bom 
in Patara and was active in this region. 
The city was later running out of interest and destroyed by the 
sand-accumulation of the Xanthos-river at the seaside, where 
wind filled the harbor and big parts of the city with dunes. In 
the last few years, big activities have been undertaken with 
excavation of the buildings, especially of the theatre. The 
theatre was exempted from several hundreds of lorries of sand. 
Since several years, groups of Turkey archaeological scientists 
aim to open the history of Patara. To get a detailed geodetic 
map of it, there came the request to the ITU. For this job, the 
balloon system seemed to be a worth full technology to map it. 
The first objective of the study was the theatre in this 
archaeological site. The theatre is about 80x100 m big. 
2.2 Control Points 
As control points for aerial photogrammetry, compact disks 
have been used. In order to reduce the reflectance, all of them 
were painted blue and red/white stickers have been plastered