Figures 4 and 8 are derived quite independently, both indicate that spatial resolutions of 5-10 m or 
better are necessary for mapping tasks. 
  
so 
  
APPROXIMATE IFOV (m) 
  
rr" 
  
  
  
  
  
3 
I I IT IY 
LAND USE CLASS (LEVEL) 
  
Figure 8. Resolution (IFOV) as a function of the mapping requirements 
for Levels I-IV land use classes (Welch, 1982). 
CONCLUSION 
Spatial resolution is more important than spectral resolution for many, if not most, mapping tasks. 
In this regard, it appears that IFOVs of approximately 5-10 m or better are required for the compilation 
of map products at scales of 1:250,000 and larger. In terms of satellite sensor system design, 
evidence to-date indicates that a stereo system with an IFOV of approximately 5 m in two (or more) 
spectral bands (from which color composites can be produced) will yield about 80% of the information 
normally required for topographic- and land use maps of 1:250,000 to 1:50,000 scale. 2 «1a 
ACKNOWLEDGEMENTS 
The author gratefully acknowledges the contributions of Dr. Yi-rong Ann Hsu, and Messrs. E. Lynn — 
Usery and T. R. Jordan, University of Georgia, and of Professor Gordon Petrie, University of Glasgow, 
in the preparation of the map products. 
REFERENCES 
Anderson, J. R., E. E. Hardy, J. T. Roach and R. E. Witmer, 1976. A Land Use and Land Cover Classifica- 
tion System for Use with Remote Sensor Data, U.S. Geological Survey Professional Paper 964. 
  
United Nations, 1978. Characteristics and Capabilities of Sensors for Earth Resources Surveys. A 
study prepared by the Committee of Space Research (COSPAR) of the International Council of Scientific 
Unions. 
Welch, R., 1982. Int. J. of Remote Sensing, in press. 
Welch, R. and C. W. Pannell, 1982. Photogrammetric Record, 10 (59): 575-586. 
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