s and 
with 
90). 
- re- 
wed 
elles, 
B refers 
e soils, 
etery 
pre- 
the 
rs 
cs, 
/15 ooo, 
000 
and 
march 
Fig. 3c Highway under construction 
The linear featured scheme is produced by signs X, 1 and =.As 
in fig 3b, sign B lies on both sides (less reflecting surfaces). 
Fig. 4 An example of assisted classification results : Gosse- 
lies (Northern fringe of Charleroi) 
The point of the unassisted classification was the confusion of 
brushwood and medium density dwelling areas, and the too high 
number of transitional classes between urban and rural land 
uses. The assisted procedure has yielded a good discrimination 
between woods (classes 3, 4,5) and houses (1 & 6); it also has 
reduced the number of classes typical for warehouses from 4 to 2 
(classes 2 & 8) and the number of of urban-rural transitional 
classes from 3 to 1 (class 7). The problem remains of the meaning 
of the class 13, in some cases built up ground, in other cases 
crops such as corn. One can easily see in the upper part of the 
image sample : an industrial estate located along a highway (the 
discrimination of which has also been improved), in the left 
part an urban center fringed by small industries and warehouses, 
in the lower part an airport with its terminal, in the middle 
a private park. Classes 17 and blank correspond to bare grounds 
or rural land uses. 
Aerial photograph : By courtesy of Ministere des Travaux 
Publics, Bruxelles, Feuille 46, Charleroi, 1973, 46-418 
46 — 519.