Range 
-17 to +12 meters 
-8 to +8 meters 
-8 to +13 meters 
locations determined by conventional surveys. The initial results using 
a total of 64 points were as follows: 
Error 
E 7 meters 
N 6 meters 
H 7 meters 
Other tests conducted by the U.S. Defense Mapping Agency compared APPS 
determined positions to those obtained by photogrammetric triangulation. 
The results from 92 total points were as follows: 
Error 
E 5.6 meters 
N 5.6 meters 
H 2.8 meters 
Further analysis of these errors shows that there are three general sources 
of error: the data base, the APPS mensuration process, and the error due to 
t ' \ , * . 
the human correlation of image detail from the stimulus image to the data 
base. The combined statistics from a number of independent tests show the 
following distribution of errors: 
Data Base 5.7 meters 
APPS 4.1 meters 
Correlation Error 7.3 meters 
Absolute (RMS) 10.1 meters 
The data base error shows the deviation of the location of points derived 
analytically from the photographs to those derived from ground survey. 
U