CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
the aerial photos (1:15000) and by the resolution of the scanner
(15pm). The colours of the infra-red images were converted by
means of a colour transformation- and intensity matrix, with
additional parameters of practical experience into images of
natural colouration*.
Again this map, including the revised photogrammetric line
analysis and the city map, the latter generalised to a scale
1:5000, resulted in a GIS (Geographic Information System).
Contour line, inclination and shaded relief maps were derived
from the terrain model.
One aim was to create a layer of the archaeological resources
for the orthophoto map scaled 1:5000. For that purpose the
digital city map of Ephesos had to be generalised. This map was
generated by surveying and by digitising existing paper plans
(scales between 1:50 and 1:200). The plans were tied up
through measurements of control points in the field; then the
digitised plans were converted by a neighbourhood
transformation (Hardy, 1972) (multiquadratic interpolation);
thereby an optimal absolute infitting under maintenance of
inner geometry of the drawings was obtained. Figure 2 shows
the area of the East gymnasium with generalised vectordata and
the underlying orthophoto in natural colouration.
Infra-red pictures are often used for photo interpretation work,
because of their special properties. The emulsion of the film is
sensitive to the spectrum of near infra-red light and represents it
in red colour. The vegetation emits strong infra-red rays and
therefore allows to distinguish between different plants.
Because of the strong influence of the ground conditions on the
vitality of the plants, it is possible to see them at the colour
gradation in the photos.
To verify the aerial photo interpretation an area south of the
Arkadiane was chosen, which is a colonnaded street leading
from the theatre to the habour. Here the Byzantine city wall (in
Figure 3, drawn in blue) encloses a rectangular area* **.
Archaeological excavations took place: at the gate on the
southside of the Arkadiane, at the street leading south, at the
westgate of the Agora, at the so called gate "Medusentor" and at
the street leading east to west. On the aerial photograph a
rectangular place is visible, showing a circular monument in its
centre, the place is surrounded by a pillared hall. The square
measures on its sides 85 m and the diameter of the central
circular building is to 20 m.
5. WATER CONDUIT
In ancient times Ephesos was supplied by several great water
conduits. One of them starts in the south at a place called
Degirmendere, it has a total length of 43 km (Ozi?, Atalay,
1999).
Starting point for the following computations was the
consideration that ancient water conduits often follow the
topography. There is the question, if it is possible to model
approximatly the course of the water conduits by applying a
mathematically defined terrain surface of DTM. If it is
Carried out by Prof. Dr. Dipl.-Ing. J. Jansa, Institute of
Photogrammetry and Remote Sensing, TU-Vienna.
** F. Hueber, Ephesos (1997). Gebaute Geschichte (1997) pp.
51.: "Der Platz südlich des Viersäulenbaues ist heute an der
byzantinischen Stadtmauer zu erkennen, die seine
Außenwände als Teil der Befestigung mitbenutzte. Sonst
sind von diesem Platz nur noch einige Säulenbasen der
Kolonnaden erhalten."
succesful, it could optimize fieldwork and model areas where
no architectural remains are left.
In this case an elevation of 62 m on the aerial analysis was
messured at the aqueduct Arab-dere-kemer, which is the nearest
to Ephesos. By following the calculated run of the water
conduit in the direction to Ephesos on the DTM and by
assuming a fall of 0,5 Promille*** for the calculations, the
course as shown in Figure 4 comes out. This results corresponds
well with an elevation of 60 meter over the sea proved by
Forchheimer (1923) the water conduits on the north side of the
Bülbül Dag.
5.1 Errors
Which errors can occure by simplification?
a) By the calculation every valley is driven in the full
length without any aqueduct, therefore a greater distance
has to be covered and more difference of altitude "is used".
b) b) Also a terrain saddle, which in ancient times was
used to shorten the distance by digging a canal or a tunnel,
therefore construction expense was reduced.
Both errors are model errors, which are leading to the
assumption of a water conduit lying too deep in the area of
interest.
What are consequences of errors in altitude necessarily lead on
the model, and what are the consequences of changes of the
landscape on the determination of the position of the water
conduit?
c) c) In a very steep area of 50% inclination as it occurs
on the north slope of the Bülbül Dag, an altitude error of
±lm and an error of position of ±2 m has to be calculated.
d) d) If you have now an inclination of 10%, 1 m would
amount to an uncertainty of the position of ±10m.
e) e) Having an even area, it is not possible to estimate
the line course only in presumtion of an incline.
Those cases show very clear by the importance of the
stochastically model for DTM, to be able to value the reliability
of the results. For the model calculations in this place discussed
only the starting point and the terrainmodell were assumed. If
there could be introduced more points, that define the water
conduit in the field and are surveyed, the calculations could be
improved.
REFERENCENS
Forchheimer, Ph., 1923. Wasserleitungen, In: Forschungen in
Ephesos Band III, Wien, pp 233.
Hardy, R.L., 1972. Geodetic applications of multiquadratic
analysis. Allgemeine Vermessungsnachrichten 79, Herbert
Wichmann Verlag, Karlsruhe, pp. 398-406.
Hueber, F. 1997. Gebaute Geschichte, von Zabern, Mainz am
Rhein.
Özi§ Ü., Atalay A., 1999: Fernwasserleitungen von Ephesos, In:
H. Friesinger - F. Krinzinger (Hrsg.), 100 Jahre Österreichische
Forschungen in Ephesos. Akten des Symposions, Wien 1995, pp
407.
*** Ozi§, Atalay (1999) prove a incline of 5 per mill, this shoud
be an errat, because my estimation of the elevation
difference from the spring to the aqueduct including the
length of the water conduit results a value of about 0,5 per
mill.
