FROM THE AERIAL PHOTO TO HIGH RESOLUTION SATELLITE IMAGE.
TOOLS FOR THE ARCHAEOLOGICAL RESEARCH
1 + 2 . . 3 TT s ;
O. Georgoula, ^D. Kaimaris, "M. Fsakiri, ^P. Patias
l : Ey + . 3 : S
Assistant Prof.," PhD Candidate, "Assistant Prof., * Professor
Department of Cadastre, Photogrammetry and Cartography, Aristotles University of Thessaloniki, Greece
olge(@topo.auth.er , martsak(@eng.topo.auth.gr
ThS20
KEY WORDS: Remote Sensing, Quickbird, Archaeology, Ortho, Fusion, Interpretation
ABSTRACT:
The aim of this project is to evaluate the possibilities that the high resolution satellite image offers in the field of archaeological
research. More specific, the present study concerns the identification of buried archaeological remains with the aid of the Pan-
sharpened (fused) image Quickbird-2. For this purpose, the fuse
d image (spatial resolution 0.70m and spectral resolution 4 bands),
that covers an extended area of the archaeological site of Philippoi in N. Greece, has been used. The new image has been produced
from the fusion of two ortho images. The latest have been derived from the panchromatic image and the multispectral image as well.
The generation of the above two ortho images has been based on a DTM of the area, photogrammetrically produced, and on the
Quickbird sensor model. The fusion has been established with tl
ne PCA technique. The fused image has been evaluated with
statistical criterions. Enhancement technique, as PCA was applied to facilitate the optical interpretation for the detection of the
revealing traces. Comparing the interpretation results with the results coming out from previous research, based on photogrammetric
data, has been found out that both of them converge. The advantage of the use of the fused image is that it offers additional valuable
information to the archaeologists and/or to other technology oriented experts, as for example information about the land use etc.
Additionally, the high spatial resolution of it offers the possibility for an accurate surveying of the detected traces.
I. INTRODUCTION
The use of the aerial photos for surveying and documentation of
Archaeological sites is well known. The application of digital
photogrammetric methods of processing, often of a large
number of aerial photos, gives the necessary outputs as maps,
DEMS, orthos, 3D models etc., for the monitoring of historical
sites. Of special interest is the case, where the aerial photo is
used for the detection of buried archaeological remains, which
under the proper conditions, when viewed from the air are best
identified. In this case the ortho, which combines the
quantitative information of a map and the thematic information
of a photo, plays a significant role in archaeological research.
At the archaeological site of Phillipoi in Northern Greece
excavations take place for the last 90 years. During the
excavations, a small part of the famous Via Egnatia of the
Roman period has been uncovered. In 2003, a project has been
carried out in the Department of Cadastre, Photogrammetry and
Cartography in Aristotles University of Thessaloniki.
(Georgoula et al, 2003). It concerned the processing of a block
of 11 vertical acrial photos of the major area of the
archaeological site of Philippoi. The photos was at 1:15,000
scale and they was captured in September 1994. The initial
visual interpretation, via stereoscopic vision, led in the location
of a lot of traces. The second stage was the digital
photogrammetric process of the aerial photos and the
production of a DTM and an orthomosaic at scale 1:5000. For
this, the aerial photos were scanned at 1200dpi, that means the
resolution of the digital images was approximately 0.3m. The
visual interpretation of the orthomosaic of the entire area of
interest, was of great help. Fifteen (15) traces were correlated
between them. The initial information, provided by the
interpretation, was cross-evaluated with additional information
coming from other sources, like cartographic data, historical
sources and information from the archaeological excavations.
Specially, the particular processing of old cadastral maps (1928,
1938, 1940, 1957, 1960) gave information about the old
geomorphology (old streams, old ownership boundaries, etc),
and thus, for many traces our initial estimations have been
confirmed. They were traces of the old geomorphology of the
region. This information, in principle of non archaeological
interest, it has been very useful in two directions: firstly, in
restricting our attention in a smaller number of traces and
secondly, for the reconstruction of the ancient landscape. Thus,
finally our attention was focused on 6 features. The final
conclusion is that four (4) of these traces concern parts of Via
Egnatia and the fifth feature is a part of a fortification wall. The
last one is located on the top of a small hill and it concerns a
buried construction approximately 53x47m, till now unknown,
even for the archaeologists.
As the results of this research were very encouraging, it was
decided to continue the efforts in the same direction with the
aid of satellite images. In the past, there have been many studies
using satellite imagery. These projects have been restricted
mainly to geomorphological analyses using Landsat SPOT
images or other data (Boehler, 1999, Comfort, 2001,
http:/www.irex.org/programs/completed/blacksea/trelogan.pdf,
http://Www.geoinformatie.nl/cgi/projeets/bers/multisensor/repor
t1/10.htm, http://Www.caa2002.er/abstracts papers/83.html,
http://www.culturalsite.com/petra/petrakaplan97.html,
http://wwwghec.msfc.nasa.gov/archeology/arenal.html,
http://www.personal.rdg.ac.uk/-sgswitke/rescarch.htm).
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