GVII-42 
PHOTOGRAMMETRIC ENGINEERING 
which combine the use of aerial photos with ground techniques. 
Soil surveys use aerial photos: “The use of air photographs in soil surveys” 
was the subject of a discussion at a meeting of the photogrammetric society in 
March 1954 which was opened by Dr. A. Muir (Photogrammetric Record, Vol. 
1, No. 6, pages 50-57). The interpretation of air photographs continues to be 
used by the soil survey of England and Wales in conjunction with ground meth 
ods and some experimental work has been carried out in an attempt to assess 
the value of photographic interpretation methods in Britain (op. cit, p. 53). 
The most extensive and detailed investigation of soil conditions carried out, 
in part, by photographic interpretation methods has been undertaken in Iraq 
by Hunting Aerosurveys, Ltd. The scheme is part of a soil and land classifica 
tion survey on four major irrigation projects in central Iraq and is being pre 
pared for the consulting engineers to the Iraq Development Board. This work 
involves a great deal of ground work, with a team of 10 men permanently in 
the field over a period of 8 months, including 8 soil surveyors, 1 chemist and 
1 soil engineer engaged on field permeability tests. In addition the team has in 
cluded for part of the time an ecologist and an agriculturalist, with a visit from 
a consultant specializing in the reclamation of salty land. 
The work has been based on 1:15,000 photography which has proved of 
great value in (pedalogically) rather difficult country. The ancient irrigation 
layout is clearly visible on the aerial photographs and provides clues to many 
soil problems which would have been very puzzling without their aid. The 
full survey involves soil and land classification (for irrigation) maps at 1:50,000, 
together with a comprehensive report recommending systems of agriculture for 
the new areas when brought under irrigation, and the size of holding which 
would support a settler family at a reasonable standard of living. Mosaics at 
1:20,000 and 1:50,000 have proved very valuable as working maps for the field 
parties. It should be emphasized that initial photographic interpretation was 
used to identify major topographical units and that detailed interpretation was 
only attempted in close association with the most elaborate field checking and 
research. The project is, however, demonstrating the applicability, under such 
conditions, of photographic interpretation methods even in areas of arid and 
saline soils. 
Detail soil maps rely upon field identification and delineation but use aerial 
photos to guide placement of boundaries. Complexity of landscape reduces ac 
curacy of photo interpretation as well as the importance of soil properties not 
associated with land farms. Semidetailed soil maps that rely upon photo in 
terpretation produce moderate to good accuracy in simple landscapes. These 
are satisfactory for associations of agricultural uses but field checking is essential 
for most objectives. Those soil features, closely associated with prominent land 
farms and vegetation, most aid photo interpretation of soils. Maps for farm 
planning require detailed soil maps and extensive field work. This combination 
will generally produce maps ranging from 80 to 90 per cent accurate. 
Pasture surveys are helped by aerial photos: In Jordan the U. S. Operations 
Mission is working on methods of pasture improvement, livestock being the 
mainstay of the bulk of the population. As a necessary first step in pasture im 
provement or vegetation and soil conservation measures, a basic survey of pres 
ent conditions is being carried out using the complete photographic cover of 
Jordan obtained in 1953. Preliminary work by an ecologist, to determine the 
extent to which the existing photography could be used in mapping uniform 
vegetation types, was undertaken in the spring in 1954. In the spring of 1955 a