Tsioukas et. al., 2001), while major issues in visualization of
photogrammetric data are analyzed in (Patias, 2000, Patias et.
al., 2001).
As a first step, the user is presented with the background image
of the area (Fig. 3a) from where he can choose to follow a real-
video tour of the denoted ones in red. Each tour line is linked
with respective video MPG files for this reason.
He can either choose to fly over the city through virtual video
sequences (Fig. 3b). In this case the he can also have an
overview of the protected sites, which are 3D reconstructed and
can be viewed as 3D rendered blocks.
The user can further choose to go "on-ground" and walk
through the city center via the virtual walk-through video
option. Choosing one of the available routes (Fig. 3c) he can
examine closer the protected buildings with their surrounding
area and view their facades in 3D (Fig. 3d).
The overview of
the historic center
familiarizes the user
with the space
: Byzooming into
the protected
buildings are
| projected in
yellow color
For each building
selected a number |
of information
can be viewed
HTML
pages |
EE
HTML |
In Pages |
ei CCESS
©»
s Piles with
Al | HTML
upport
Short
presentation Full DataBase
of the Information
building with search
capabilites
Ee
Existing PDF ;
plans, —I | Files E
sections, Lm
facades, sadi
Lu à A complete
— TL historic and
| JPEG :. à architectural
| Files LA Le documentation
with proper links
to references
and bibliography
a"
Photographic § _
Archives § 8 New photo
archives
Figure 4. Overview of the web-based Information System
5. INFORMATION MANAGEMENT
AND WEB-BASED DISSEMINATION
Most existing urban archives are based on either localized map-
pings in form of plans, or on descriptions and photographs of
objects, or simply on normal text or database reports of studies
of the areas of interest. In contrast, the developed system is
completely digital (allowing thus the easy up-date of the infor-
mation, as well as its dissemination), refers all data to single
coordinate frame (allowing thus the multi-layered study of all
available data), it is multi-format (allowing thus the concurrent
use of vector, raster and textual data), and finally is "intuitive"
in use (further ensuring data use and dissemination to all con-
cerned users, even to unskilled ones).
Besides the 3D visualization techniques and VR products (3D
objects, 3D city models, video sequences, etc), which are
included in the system, for the widest dissemination of the
information, it is necessary for the implemented system to be
web-based.
The developed Information system has been designed for
viewing at 1024x768 resolution through either Explorer or
Netscape web browsers. It is based on HTML procedures with
appropriate links to Acrobat PDF files (for historical,
architectural and morphological information), to JPG files (for
current or archived images, as well as scanned engineering
plans), Access DataBase MBD files (for administrative and
historical information) and MPEG video files (for either virtual
or real video sequences). Figure 4 gives an overview of the
developed system and its functionality.
6. CONCLUSIONS AND OUTLOOK
We presented the development and functionality of a 3D
modelling, visualization and Information management system
for the historic center of Thessaloniki, and more specifically its
core part, which has been destroyed by the fire of 1917. The
scope of such a system is multifold : it aims at the development
of a digital archive system for the city's architectural heritage, it
aims at web-based dissemination of information to all involved
parties and to the general public, it aims at the development of
an Information management system in order to support a range
of uses. It should be noted that, the use of such a system is
quite wide, as relevant literature shows: ie. disaster management
(eg. Hatamaya, et. al, 1998), urban climate studies (eg.
Takashi, et. al., 1998), studies on changes of urban structures
(eg. Hashimoto, et. al., 1998), etc.
Future developments will include the direct connection of video
images to the underlying 3D model, in order to create a unique,
intuitive user-interface. This way the user will just point on the
video image and the information of the underlying 3D model, as
well as the Information System database will be retrieved (see
also Shibasaki, et. al., 1998).
REFERENCES
Bartolota, M., S. Di Naro, M. Lo Brutto, P. Misuraca and B.
Villa, (2000): Information Systems for preservation of
cultural heritage, JAPRS, Vol. XXXIII, Part B5/1, Com. V,
Amsterdam 2000, pp. 864-870.
Boehler, W., G. Heinz, Y. Scherer and M. Siebold, (2001):
Topographic information in cultural and natural heritage
visualization and animation, Proc. of International
Workshop on Recreating the Past "Visualization and
Animation of Cultural Heritage", Ayutthaya, Thailand.
Boulanger, P. and J. Taylor, (2000): The Virtual Museum - Data
generation and Visualization, IAPRS, Vol. XXXIII, Special
Sessions, Supplement, Amsterdam 2000, pp. 4-9.
Chikatsu, H., and T. Anai, (1998): Relics modeling and
visualization in virtual environment, IAPRS, Vol. 32, Part 5
"Real-Time Imaging and Dynamic Analysis”, Hakodate,
1998, pp. 528-532.
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