he 
to- 
lu. 
ng 
ed 
re 
Figure 1: 
The 
Oey Uy » 
! 
  
    
   
    
   
     
  
    
   
   
    
Estimation of terrain- class proportions by a 
sytematic sampling on aerial photographs 
  
    
  
— — — — — 
  
  
  
four terrain classes and their proportions in the Figure 
flat land on a low level, 
slope bearing to the left, 
flat land on a high elevation, 
slope bearing to the right,