Figure 4. It is evident that a significant increase in the completeness of detail beyond the 40-50% 
measure of its information content. For example, the maps prepared from the MSS, RBV, and ETC images 
were digitized in 1 3/4, 1 1/4 and 5 hours, respectively. By comparison, the detail from the 1:250,000 
scale topographic map for the same area required about 5 hours of digitizing effort, and nearly 24 hours 
were spent on the 1:50,000 scale topographic map. From these statistics, it appears obvious that the 
MSS and RBV image data are of inadequate resolution for the compilation of maps at 1:250,000 scale or 
larger, and that even the ETC images are of only marginally sufficient resolution for 1:250,000 scale 
products. 
The amounts of detail compiled from the ETC, RBV and MSS maps were then ratioed to comparable data 
gets obtained from the standard 1:250,000 and 1:50,000 scale topographic products to provide percent 
completeness values (Figure 3). Relative to the 1:50,000 scale map, the MSS and the RBV image data 
provide about 40% of the detail necessary for map compilation, whereas the higher resolution ETC photos 
yield over 60%. Improved percent completeness values are obtained when the comparison is made with the 
more generalized 1:250,000 scale map product. In this case, the MSS and RBV images provide 40-50% of 
the detail and the ETC about 70%. 
COMPLETENESS RELATIVE 
TO 1:50,000 AND £250,000 
100 SCALE TOPOGRAPHIC MAPS 
REL. REL. 
80 1:50,000 1:250,000 
ETC 
    
  
% COMPLETENESS 
  
  
  
  
  
Figure 3. Completeness of detail relative to standard 1:50,000 and 
1:250,000 scale topographic maps. 
It is apparent there is a relationship between resolution and percent completeness of detail (Welch 
and Pannell, 1982). This relationship, based on analyses of satellite data to-date, is represented in 
level only occurs as IFOVs are improved to 10 m and better. Obviously, this is a very generalized. .—.. ...— 
relationship, but nevertheless, it is evident that spatial resolutions of better than 10 m (and 
probably better than 5 m) are required for the compilation of maps of 1:250,000 scale and larger. 
Multispectral and stereo data may offset spatial resolution requirements to some extent, but spatial 
resolution is the dominant factor. 
IFOV vs COMPLETENESS 
or 
70H 
20 
  
  
o rede ic A 
O 10 20 30 40 50 60 70 80 SO 100 
% COMPLETENESS 
Figure 4. Resolution (IFOV) as a function of Z completeness 
of map detail. 
RESOLUTION REQUIREMENTS FOR LAND USE MAPPING 
The argument for spatial resolution can be extended to land use maps. If the relative size of the 
urban built-up areas from 50,000 and 500,000 population in different countries are compared, it is 
evident that a city in China would occupy about 1/30 the area of a city of equivalent size in the United 
52