from satellite images from either SPOT (Fig. 2a), or IKONOS 
(Fig. 2b, 2c). In color, the city block structure gives the impres- 
sion of the population density. 
In addition to the above, and referring to much larger scale, a 
geometric database of 250 buildings, under official protection, 
has been developed. For this reason, the buildings have been re- 
constructed and rendered in 3D, by usual stereoscopic photo- 
grammetric techniques from the aerial images. Each building 
has been "cropped" at the existing DTM level, in order to re- 
duce visual "floating" in closer looks, which can be eventually 
caused by inaccuracies in DTM modelling. 
  
(a) The greater metropolitan area of Thessaloniki 
(as shown in Spot images) 
  
(c) Extract from Ikonos image depicting the current (March 2000) status of the damaged area 
Figure 2. Satellite views of the historic center of Thessaloniki. 
For each building the ground plan as well as at least one roof 
point (for delivery of the building height) have been 
stereoscopically measured on the aerial images. From these 
measurements a control point frame has been also derived for 
the reconstruction of the main facades. This frame will be used, 
later on, for the rectification of the digital close-range image of 
each building facade. 
Each building's main facade has been visually documented by 
close-range, terrestrial digital images with the use of amateur 
digital off-the-self 3 MegaPixel cameras at an average scale of 
1: 200. All images were taken in winter-time, in order to reduce 
obscured areas due to tree canopies and shadows. A total of 250 
images have been acquired. 
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