Si 
he subject 
d 
then 
on which 
arances and 
signature 
ure 3. 
841 
key in the 
test area 
oduced 
in excess 
ted 
given the 
ing TU 
nd french) 
tion. The 
ying where 
The two 
e divided 
each 
, using the 
stereo 
nd 
>d with a 
10km x 10km 
graphy. 
the stereo 
irked on the 
lis zone was 
;d. 
1 using a 
)hoto 
id and each 
An example 
figure 4. In 
i heavier 
This line 
and the 
irately. 
~e were two 
ich 
pensating 
then 
intire CU 
atification. 
a were very 
tion results 
suits were 
n average of 
U’s 
d TU 
instances 
etation 
sely 
n so 
lated. In 
mpleted 
ground 
ap contained 
ing from the 
getation 
S/V/LF 
Using the 
e CD's were 
ered to 
both noted 
id their 
len added and 
•. The most 
lap with the 
id principal 
741 
625 
.325 
841 
841 
325 
841 
62f 
SERIES 841 
Figure 3. One of the sterograms of the photo interpretation key used in producing the soil/vegetation/land 
form base maps. The key was developed to systematize the interpretation of the medium scale aerial photography 
used to extrapolate site-specific data to the entire zone shown in Figure 1. This example shows one of the 
stereograms developed for the terrain unit series 841. In general several stereograms are produced to show the 
photo appearances of typical examples of each terrain unit and acceptable variants. To the left in the figure 
is the stereogram which has the specific terrain unit labled. To the right is a delineation and interpretation 
which shows the subject terrain unit in association with other terrain units with which it normally occurs. 
This product is presented so that the interpreter can identify the subject terrain unit, not only by it's own 
characteristic photo appearance, but also by it's patterns of association. 
Table 1. Terrain units, and their relative 
surface areas, mapped in the Mirria and Matameye 
arrondissements 
Matameye 
Mirria 
Figure 4. An example of one of the zones interpreted 
using the IGN aerial photography and the photo 
interpretation key. The figure shows the delineated 
terrain units and their identifying codes. 
cities, towns and villages. The results of the 
mapping effort in the test area are presented in 
Table 1. Listed are the TU's identified in each 
arrondissement and their relative surface areas. 
3.6 Surface area of forestry types 
In order to determine the surface area of forestry 
types in the area each TU must be evaluated for it’s 
relative forestry value. Each TU description was 
TU 
area (sq km) 
area (sq 
124 
2.7 
76.0 
127 
0.0 
32.0 
141 
54.4 
200.7 
163 
80.6 
229.8 
221 
37.7 
35.7 
331 
72.4 
77.9 
431 
125.1 
1208.0 
436 
12.0 
4.9 
437 
15.8 
107.1 
512 
8.8 
1175.6 
621 
32.2 
864.9 
625 
42.5 
43.7 
629 
1.6 
0.0 
705 
2.2 
361.8 
715 
37.0 
965.2 
741 
1531.6 
6170.6 
821 
0.0 
355.4 
841 
0.0 
4.9 
845 
0.6 
0.0 
849 
6.7 
78.9 
analysed and placed in one of three basic categories 
as follows: 
I Primary forest land: lands which naturally 
support forest product producing 
vegetation types and whose primary 
use is forestry 
II Marginal forest lands: lands which support 
vegetation types which yield forest 
products, but would require significant 
413 
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