accurate and are carried on in a quicker way, when the vegetation is in an advanced state, and the development 
of the method described under 2) above, and we can record the changes, year to year, more accurately and 
within a shorter period. 
19.  Lappalainen, V. 
Finland 
PHOTOGEOLOGIC INTERPRETATION IN ROAD PLANNING IN FINLAND 
The National Board of Public Roads and Waterways in Finland has had different kinds of aerial photos 
analysed for road planning. It has been established that photogeologic interpretation is well fitted for 
preliminary planning of roads in conditions in Finland when there is a rapid need to get regional information 
about the general distribution of the technical quality of the bedrock and the ground. Stereopairs photographed 
from the altitude of 4500 m and 2000 m on the scales of 1:22,000 and 1:13,000, respectively, have been used 
in the research work. Two road lines in middle Finland were photographed for this investigation. These areas 
differ to some extent in their geologic structures. 
Black and white, colour and false-colour images were analysed stereoscopically and the results have been partly 
controlled by field investigations. 
As a result of interpretation, it is possible to distinguish frictional and cohesive soil group regions, important 
for geotechnical planning, and soil formations like sand and gravel formations fitted for road construction 
material. Areas differing in their frost susceptibility can also be distinguished. In addition it is possible to 
determine areas where temporary softening of the surface of gravel roads is probable. Under certain 
conditions, the ground's response to digging can be preliminary estimated. When comparing different kinds 
of photos it has been verified that the information about the ground given by colour and especially false-colour 
images is much more extensive and serviceable than information of black and white photos. 
Photogeologic interpretation speeds up road planning. Also the time-consuming mechanical investigations of 
the ground can be directed and critical sites, which mostly results in smaller expenses of planning. 
20. Leroux, P. 
France 
METHODOLOGICAL PHOTOINTERPRETATION SURVEY AS PART OF A 
SPECIFIC REGIONAL IMPROVEMENT OPERATION 
This survey covers the compiling of cartographic documentation for improving the olive plantations in Great 
Kabylia, Algeria. It appeared necessary to extend this operation to include an inventory of ground use. The 
credits available were not sufficient for making new airphotos, so the working basis was both the 1:50,000 maps 
(1959-1966) and the existing 1:25,000 panchromatic airphotos (1959-1960). 
After the work had been done by a preliminary multidiscipline mission, the photos were interpreted and three 
types of maps compiled and reproduced on transparent supports. These maps were of ground use, olive 
plantation renovation and olive plantation improvement. The first map includes details of small plots. The 
second takes agronomic, geographical and climatic data into consideration. The third shows areas to which the 
olive plantations may possibly be extended, including the new possibilities offered by the current campaign to 
halt some crops (grapes) as well as the restrictions imposed by threats of erosion. All three maps can be 
superposed on the topographic map or on one another. 
21. Leroux, P. 
France 
AERIAL PHOTOGRAPHY AND THE FIGHT AGAINST LOCUSTS 
The damage caused by locusts is considerable in some parts of the world. To fight this plague, these insects must 
be prevented from gathering together in the areas where swarms are formed. In the interior Niger delta in 
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