4 
indications about differences in soil condition. Therefore not only natural, but also man- 
made elements are used. 
Not all elements always point to important differences in soil condition. If on one 
  
10 
(0 
11 L 
he 
  
  
  
Fig. 2. 
veconnaissance soil map of the same region as indicated in fig. 1, but surveyed in 
the field without the application of photo-analysis. (By courtesy of the Netherlands 
Engineering Consultants, The Hague, Messrs. Dwars, Hederik and Verhey, Civil-En- 
gineering, Amersfoort, and the Netherl. Org. for Reclamation of waste lands, Arnhem. Soil 
Survey by Dr. K. v .d. Meer). 
place, for instance, a difference in a certain vegetation or land use indicates a soil boundary, 
on another place this difference is not important at all. The value of the analysis is there- 
A