-2- 
In the 1971 paper it was suggested that space photographs could be 
enlarged until their equivalent resolution was about 10 line pairs per 
millimeter (¿p/mm). 
This criterion also imposed a relationship between the ground resolution 
which could be portrayed and the scale of the photoimage map product 
As will be seen shortly, these values proved conservative, and useful 
products can be made based on the criterion of 5 ¿p/mm rather than TO., 
This permits greater magnification between original photograph and 
published map, and permits lower ground resolution on the final map. 
A relationship was also derived to express the maximum terrain 
relief which could be accommodated in a single frame of imagery without 
exceeding National Map Accuracy Standards (NMAS) for planimetric accuracy 
in the published orthophoto product. 
Since it has been found that the allowable magnification can be doubled, 
the allowable terrain relief should be reduced by a half. The space 
craft sensor systems considered in the 1971 paper were: 
10 
M = recommended magnification from original photograph to 
photoimage map product 
Rp = resolution of original record (¿p/mm) 
R 
‘g 
-4 
10 S, 
m 
g 
^m 
ground resolution (meters) 
published map scale number 
h 
5H 
h « allowable terrain relief (meters) 
H * spacecraft altitude (meters) 
r * maximum radial distance from nadir point of 
original image (mm)