Estimating Map Document Quality 
  
To define and specify map output accuracy, certain assumed 
standards will be made to simplify the discussion. 
e A uniform line of 8 mils is used as the standard line 
width for compiling maps. Then line compiling skill 
causes a random error in 8 mil lines of about +4 mils 
(0.1mm) standard deviation. 
® The planimetric deviation in the manuscript due to 
the accumulated errors in the total aerial photo- 
grammetric process is estimated to have a standard 
deviation held to *4 mils (0.1mm) when compiled at four 
times the aerial photo scale. The accumulated error 
sources include those of the atmosphere, camera, film, 
data processing, printer, diapositive, and stereoprojection 
) through lenses or mechanical linkages. 
9 The eight-mil mylar documents averaging 30- by 20-inches 
are used for drafting and later printing and processing 
of separation negatives. With minimum stretching from 
normal productive handling these documents can be held 
to a random accumulated error of +4 mils. 
9 To convert line maps by a precision scanner and sub- 
sequent digital processing, it is estimated that 4-mil 
steps (or unit vectors) are sufficient to digitize a 
line and to detect the line center. The 4-mil steps 
are to be maintained at the -*l1-mil precision of the 
Scanner, resulting in the fourth source of a +4 mil error.