Preliminary Work and Identification of Goals

With the onset of research carried out by Austrian archaeologists more than one hundred years ago at Ephesos, the city and its surroundings were cartographically surveyed. Especially to be emphasized here is the work of Anton Schindler; he produced maps at the scale of 1:25,000, 1:5,000 as well as some detailed maps. That which was produced at the smallest scale (1:25,000) covered an area of ca. 16 × 11 km. and was printed in colour, with contour lines (brown), topographical features (black), water (blue) and ancient monuments (red) indicated. The maps, which in part are still used today, served on many occasions as the foundation for additional city maps. These were created with the goal of establishing map materials according to the most recent technological advances. (W. Modrijan, P. Waldhäusl - H. König, F. Steiner, G. Wiplinger).
After preliminary work in 1994 (terrestrial net triangulation and consolidation of bench marks) and 1995 (establishment of a uniform homogenous elevation frame), the creation of a digital city map with the following aims was undertaken:

In the survey campaigns of 1996 through 1998, numerous weeks of terrestrial surveys were carried out. At that time, control points for the existing archaeological analog plans and also new surveys were recorded. A ten-day GPS-campaign in 1997, with equipment graciously placed at our disposal by the R. & A. Rost Company, and with the support of the company co-workers Johann Berger and D.I. Erwin Truttmann, made possible the fixing of the new geodetic datum and the expansion of the field of bench marks.

Project Completion

Foundations: In connection with the project, a new coordinate reference frame was laid out. Using GPS, a point (MK03) was included in the international reference frame ITRF94. In a hybrid net adjustment of trigonometric measurements, leveling measurements and GPS-observations, the geodetic field of bench marks was calculated anew. The new reference frame (Ephesos Reference Frame 1998 - ERF98) is now firmly established through the ITRF94 and the Turkish system of elevations.

Geodetic:

Projection: Transverse Mercator (Gauss-Krueger) Spheroid: GRS80 Central meridian: 27° (east of Greenwich) Coordinates frame (position): ITRF94 at epoch 1993,0 Elevation reference: Turkish Ordnance survey Elevations with constant shift (from ERF98 to ITRF94): dX:= 25,952 m. dY:= 13,417 m. dZ:= 22,781 m.

Field survey: For the digital map, analog surveys of the excavations, to the extent that they existed, were utilized, with the help of geodetic surveyed control points, and new measurements were undertaken.

Analysis and digital revision of the analog archaeological plans: The analog plans are of differing quality (state of preservation, state of completion, geometric precision, etc.) and at differing scales (1:20 up to 1:200). The plans that have been digitized with AutoCAD were then transformed with a procedure in accordance with Hardy (multiquadratic interpolation) onto the geodetic control points. Thereby, a large number of neighbourhood infitting of the drawings was able to be retained, and at the same time a rectification and incorporation into the reference framework ERF98 was attained.

GPS RTK-survey of the Hellenistic city walls: Under Lysimachos, presumably in 294 B.C., the construction of a ca. 10 km. long wall to encircle the settlement was begun. On the ridge of Bülbüldağ, the southernmost of the two city hills, this city wall is today still in a good state of preservation and visible in the distance. Here the wall exhibits 39 towers - as far as are still recognizable - with three additional ones located on a northern foothill. Only one map, at a scale of 1:15,000, with a corresponding simplification scale for reduction, exists to date of this construction which is of great importance for research on the city's urban development. It was decided, as a foundation for continued urbanistic and architectural considerations, to measure the trace of the wall and its towers using GPS.
The GPS measuring system of the measuring campaign 1999 was composed of two receivers (Leica System 530) with a radio connection; in this manner the measurements could be carried out in real time (Real Time Kinematik - RTK) and the desired actual measurement accuracy during the measurement work could be constantly controlled. Since at Ephesos a coordinate frame (ERF98) was used that was composed in ITRF or WGS84 in a constant shift, it was possible at all times to check the absolute coordinates on a Rover (= portable GPS-receiver).

Picture Captions
Fig. 1: GPS-measurement on the Bülbüldağ
Fig. 2: Digital groundplan of the so-called Prison of St. Paul
Fig. 3: View of the so-called Prison of St. Paul

Bibliography:
A. Schindler, FiE I (1906) 234-236 (zur Stadtmauer: A. Schindler (1896), ÖAI-Inv. Nr. 2010/1a).
J. Keil, ÖJh 15, 1912, Beibl. 183-196.
R. L. Hardy, Geodetic applications of multiquadric analysis, Allgemeine Vermessungsnachrichten 79, 1972, 398-406.
St. Klotz, ÖJh 67, 1998, Beibl. 37.
Ü. Öziş - A. Atalay, Fernwasserleitungen in Ephesos, in: F. Krinzinger - H. Friesinger (Hrsg.), 100 Jahre Österreichische Forschungen in Ephesos. Akten des Symposions Wien 1995 (1999) 405-410.
Th. Marksteiner, Bemerkungen zum hellenistischen Stadtmauerring von Ephesos, in: F. Krinzinger - H. Friesinger (Hrsg.), 100 Jahre Österreichische Forschungen in Ephesos. Akten des Symposions Wien 1995 (1999) 413-419.