a 
J 
graprs, For the civil engineers, the agriculturist, the socioloists and the 
economist aericl photographs were important but not essential. 
Panchromatic, wide-angle photographs were ihought desirable by all experts. 
Eardly any of the experts had sufficient practical experience with other ty- 
pes to be able to judge this matter. Nevertheless they consider it quite pos- 
Sible that use of other cameras and film-filte- combinations in aerial pnoto- 
graphy will be useful in future for resources surveys. 
3e Seales of A.F. 
The following answers resulted from the questionnaires 
a. For detailed surveys, aerial photographs should be within the scale limits 
1:10,000 and 1:30,00C, This is based on the following specification: 
for soil surveys 721:315,000 — 1:25,009 
for geology -1:20.000 = 1:30,00C 
for engineering -1:10.000 — 1:20.,000 
for agriculture -1:10,000 - 1:20,000 
for sociology -1:10,0C0 - 1:20,000 
b, For a semi-detailed survey, the scale of the aerial photographs ranges 
from 1:20,000 to 1:40.000 according to the specification: 
for scil survey —1:20.000 — 1:30C.000 
for geology -1:30,000 - 1:45,.000 
for geomorphology -1:25,000 - 1:4C.000 
for agriculture -1:20.000 «= 1:30.000 
sociology -1:20,000 = 1:3C.,C00 
c. For reconnaissancc and exploratory surveys aerial photographs should have 
Scales between 1:40,000 and 1:2100,000, This rather wide range in scales 
is due to the fact that only a few experts had had experience with proto- 
graphs on scales smaller than 1:60.000. 
Specification: 
for soil surveys —1:40,000 - 1: 10,00€ 
for geology -1:50,000 - 1:100,000 
for geomorphology -1:40,000 - 1; 70,000 
for agriculture —1:40,000 - 1:50,000 
for sociology —-1:40,000 - 1:50,000 
for agric. economy —1:40,000 - 1:50,000 
4. Photo-mosaics 
Fifteen resources surveyors regarded as desirable uncontrolled photo-mosaics 
at least. In areas with strong relief some experts required controlled mo- 
saics, lor the agriculturist and the sociologists photo-mosaics take the pla- 
ce of aerial photographs because stereoscopic vision is not essential for 
them,