It is obvicus that the more features are shown on the map the 
shorter must be the cycle of periodic map revision which will require 
more time, or more personnel and consequently more funds. This means 
that mapping of too many features which is equivalent with mapping a lar- 
ger amount of non-permanent features has a delaying effect upon mapping 
progress (area wise) and consequently results in a decrease of the contri- 
bution of mapping upon the national economy. 
If on the other hand maps are not kept up-to-date they rapidly loose 
in value and consequently their contribution to the national economy di- 
minishes at a corresponding pace. This is illustrated in Figure 2. 
Values of Maps not Kept up to Date 
  
  
  
VALUES OF MAPS NOT KEPT UP TO DATE AS A FUNCTION 
OF TIME.