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photography taken from other sides of the site as well. In 
addition to the photo control, dimensions of certain 
important features were also taken whilst on the site. 
Photography was taken from a variety of platforms, an 
aerial hoist, walkways on and around the site together with 
ground based stations. The complex nature of the site 
meant that photography not only had to be taken from 
around its perimeter, but also from inside the site itself. 
The amount of stereo pairs taken was restricted to 
approximately fifty but could quite easily have been 
double or treble this amount. 
The plant was subdivided into logical areas. This enabled 
the photogrammetric digitising to be phased and enabled 
the client to receive sections of the site as they were 
completed. This phased delivery procedure ensured the 
client received the correct level of detail required as 
feedback was received on the initial deliveries. 
Fortunately the section of plant being surveyed was 
aligned with the overall site coordinates. This simplified 
the editing process. The editing again consisted of creating 
3-dimensional surfaced’ shapes of the main site 
structures from line strings digitised on the IMA, storage 
vessels were represented by cylinders (Chandler & 
Cooper, 1991). Using the dimensions that were taken on 
the site it was possible to undertake checks on the accuracy 
of the model. This was important because of the large 
variations in object scale on some of the photography. 
The complexity of the site inevitably meant that there were 
some areas where it was uneconomical to use 
photogrammetry within the clients existing budget. These 
ju 
  
  
  
  
  
   
     
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