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.