5 
Class III — Errors larger than 9 meters. These large errors are most likely to be 
due to incorrect orientation and are therefore not included in the 
calculation of m p . 
Class IV — Errors in reading or calculation. A survey of how the errors in these 
classes are distributed among the different series in shown in Table I. 
Table 1. Classification of the errors. 
n = the number of points. Classes of errors — see text. 
Series 
Totel 
n 
Class 1 
°/o 
Class II 
°/o 
Class III 
Class IV 
°/o 
1:10.000 Aviogon 15 cm 
1114 
84.3 
7.8 
5.4 
2.5 
1:15.000 Aviogon 15 cm 
1141 
79.0 
11.2 
5.4 
4.4 
1:20.000 Aviogon 15 cm 
1036 
80.2 
9.7 
6.9 
3.2 
1:15.000 Aviotar 21 cm 
1083 
85.5 
4.8 
5.9 
3.8 
Average 
1094 
82.3 
8.4 
5.8 
3.5 
Remarks: (') Of these, 55 near land with sparse vegetation, equal to 5% of all points — 
variation from 4.5 to 5.7% for each series. 
The number of errors in Classes II-IV together is highest, 239, in a scale of 
1:15.000, Aviogon, and lowest, 157, in a scale of 1:15.000, Aviotar. 
Among the field workers, N had the greatest number of errors in Class II-IV, with 
a total of 354 for all series while F had only 174 for the same series (A had 248). 
The sum total of errors for each series did not show any great variation, with the 
highest number of errors, 215, in series 3, and the lowest, 171, in series 4. 
Table 2. Calculated mean error for the different series. 
All field workers grouped together. 
n = number of points. m p = + y/( ) in meters. 
Series (scale) 
Sparse vegetation 
Dense vegetation 
n 
m P 
n 
m P 
1:10.000 Aviogon 
210 
2.64 
219 
3.32 
1:15.000 Aviogon 
170 
2.73 
248 
3.13 
1.20:000 Aviogon 
171 
2.90 
231 
3.88 
1:15.000 Aviotar 
187 
2.86 
240 
3.39 
Average 
184.5 
2.78 
234.5 
3.43