ons is adapted from 
4). Polygons are 
such as shape and 
allel to defined axes 
le method described 
ne initial translation 
ing a few polygons 
rst pass through the 
roach then allows 
A large number of 
ortant that they are 
image. The method 
ygons must then be 
jugate points. A 
oped at UCL is one 
94). The perimeter 
fit obtained. The 
| first developed by 
ined by a number of 
el position projected 
consideration. The 
1 the map boundary 
on are used as costs. 
changes between the 
'hange or an error in 
11 not be selected as 
nce for the fact that 
effects or geometric 
such as recognition 
ed then the required 
lute orientation of a 
sideration then three 
ailable. Model co- 
inates of one image, 
approximate surface 
d photograph within 
xact position can be 
ment modelling was 
the output from this 
ite co-ordinates. If 
n a two dimensional 
section carried out. 
OUNDARIES ON 
) 000 MAP DATA 
mated system in that 
omatic manner from 
method of polygon 
ouli and Freeman, 
imensional conjugate 
a height value so that 
1 can be carried out. 
296). 
ht was scanned using 
esulting in a -26Mb 
is 1:11 600 and the 
age is 0.50m. The 
1a 1996 
  
  
  
  
Figure 2 . The Isle of Wight original image (top left), the smoothed image (top right), the thresholded image 
(bottom left) and the edges detected in the image (bottom right) 
141 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996