1.3 Available Photographs 
Fortunately a series of amateur colour 35 mm slides were made 
available to us by two Israeli archaeologists. They happenned to 
have recently flown over the Old City with a small handheld 
camera. They appreciated our problem and kindly made copies 
of their slides for us. A sample of one such amateur image is 
shown in Figure 1. 
    
Figure 1: An oblique photograph of Old City Jerusalem 
2. DATA AVAILABLE 
2.1 Geometric Documentation Products 
In order to achieve the desired result, all available data should 
be exploited. At our disposal were all drawings produced for the 
geometric documentation of the complex. They were plans and 
elevations at a scale of 1:50, both in analogue and digital form 
(Figure 2). 
  
  
Figure 2: Sample of the geometric documentation drawings 
Moreover we also had access to all our relevant geodetic 
measurements and other technical data, such as point co- 
ordinates, angles, height differences and three dimensional 
distances. 
2.2 Image Data 
Nothing was known, however, concerning the geometry of the 
35mm slides available. They were taken with an amateur, but 
completely unknown, camera obviously equipped with a zoom 
lens. Hence the images were of different and unknown scales 
taken with various and unknown focal lengths. Moreover, as the 
camera was handheld, the images were taken at completely 
uncontrollable angles. Additionally, the copies made available 
to us were made with unknown process, a fact which may have 
  
caused even worse geometry problems. However, a rough 
estimation of the mean image scale for these photos was 
possible with the help of some known distances appearing on 
them. 
3. METHODOLOGY 
3.1 Exploiting the available data 
Since the only information available were these particular 
images, it was decided to try and exploit them to the best of our 
abilities (Modatsos, 2000). 
It was decided to implement an adjustment method, which 
would be able to calculate and determine practically everything, 
under certain circumstances, of course. This method is none 
other than the bundle adjustment method. As output products 
one may receive co-ordinates of unknown points, co-ordinates 
of image stations, camera lens attitudes and, of course, the 
interior orientation parameters of the cameras used. In such an 
adjustment the additional information available would be of 
utmost importance. 
3.2 Software Description 
For the adjustment the BINGO-F v.4 software was available. It 
is a well known bundle adjustment software with long presence 
in the market and very good reputation. The characteristics of 
this software are briefly the following: 
Complete parametrisation 
Full control of all unknowns and observations 
Possibility to perform self calibration 
Possibility for inclusion of geodetic measurements in 
the adjustment 
Ability to adjust images irrespective of their attitude 
No need for ground control points 
Complicated data snooping techniques 
No need for initial approximations, as the software 
calculates them automatically 
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For the calculations BINGO-F uses the well known collinearity 
equations and as input data it requires the image co-ordinates of 
all known or unknown points appearing on the images, the co- 
ordinates of the ground control points, the eventually known 
geodetic measurements (e.g. distances) and all the necessary 
parameters for the interior geometry of the camera (Kruck, 
1998). 
As output the software provides the co-ordinates of the 
perspective centres and the camera axes attitudes expressed 
with the help of the Euler angles, the co-ordinates of all 
unknown points involved in the adjustment and — if so required 
by the user — the parameters of the interior geometry of the 
cameras, i.e. the principal distance, the coefficients of the radial 
distortion curve and the image co-ordinates of the principal 
point. 
3.3 Data preparation 
In order to implement the adjustment, a preparation stage was 
necessary. The images available were enlarged and used in 
order to determine those detail points which would be necessary 
to produce the roof top plan. This operation resulted to a 
detailed sketch of the roof tops which was constructed with the 
help of the already available drawings, but also with the help of 
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