3 which 
systems (and 
1ce to a large 
zaluation 
lation of a 
in detail by 
to the 
use with the 
e 1:120,000 
orted by 
S — more than 
the panchromatic 
ite emulsions 
eys to be carried 
ately, the only 
d for vegetation 
not available 
icated that with 
ems and more in 
have been easier. 
hite photographs, 
at scale 1:40,000. 
ynoptic view 
itude panchromatic 
aphic units such 
tion of vegetation 
‘cultural planning 
he respective 
jion types; but it 
- 1411 - 
is also necessary to know which kind of vegetation or present land-use already 
exists on that particular site. In view of the comprehensive approach 
retained for the land resources survey of Sierra Leone, it was consequently 
decided to compile a reconnaissance vegetation and land-use map at the same 
scale as that of the land system map. Owing to its larger scale and better 
quality including resolution, the CIR photographic coverage at scale 1:10,000 
was preferred to the black-and-white products at scale 1:120,000; and as 
Shown in Fig. 3, IR black-and-white photographs which became available for a 
Small part of the country in 1918, are Superior to panchromatic black- 
and-white photographs. 
Kater and Gordon (1978) deal in detail with the compilation procedure applied 
and the detailed description of each of the mapping units identified and 
retained for presentation at scale 1:250,000 (with a final publication scale 
of 1:500,000). Table D is a summary of the legend accompanying the map, 
whilst Fig. 4 provides an example of the finalised interpretation(Gordon; 1918). 
The small scale CIR photographs proved to be ideally suited to the speedy 
compilation of the 'reconnaissance vegetation and land-use map'. Firstly, the 
relatively few photographs requiring to be handled reduced the time required 
for interpretation and mapping. Secondly, the fine resolution and high colour 
contrast facilitated an accurate and reliable identification and delineation of 
the vegetal units. Thirdly, the fact that the entire coverage was flown during 
one short season adds to the overall value of the interpretation and mapping. 
At the same time, it was found that high flight CIR photographs could be 
successfully used for a detailed study of vegetal types at a scale of 1:50,000 
or even larger. 
Other Applications 
(c) Dynamic Studies 
Qualitative and quantitative data about the land-use changes that occur within 
Set period of time may bring about useful conclusions regarding past and 
present trends. At the same time, they may assist too in the monitoring of 
land-use for planning purposes. 
It has been demonstrated (Schwaar 1978 a ) that HFAP and more in particular CIR 
imagery at scale 1:70,000 can be successfully used for such studies. Fig. 5 
illustrates the importance of 'old! photographs for mapping changes of land-use, 
etc. in conjunction with new photography; and Fig. 6 provides a comparison with 
information available from landsat data. 
Studies of this kind cover: 
- Comparative percentage and distribution of land area 
under active cultivation 
—~ Depletion of national forest resources 
— Development rate and extent of oilpalm plantations 
— Detailed studies of shifting cultivation cycles 
= Movements of human settlements 
— Extension and monitoring of alluvial mining activities 
— Erosion development and control studies