REPORT OF COMMISSION VII 
GVII-75 
Table IV 
Photo Interpretation Errors Based on Field Sampling and Expected Range of 
Error at 19:1 Odds, Bangor Quadrangle, Maine 
Soil Type 
Number of Field 
Samples 
Per Cent Error 
(Actual) 
Range of Error at 
19:1 Odds in Per Cent 
R 
73 
21 
14-34 
BG 
76 
38 
31-55 
B 
89 
28 
19-38 
G 
26 
23 
10-46 
F 
95 
24 
15-32 
S 
54 
26 
15-41 
P 
36 
14 
6-32 
449 
R by photo interpretation, were checked in the field. Fifteen of these areas, or 
21 per cent, were found to be something other than R in the field check. The 
statistical analysis indicates that, based on this sample, the expected range in 
error for the entire quadrangle sheet for the R soil type, at 19:1 odds, ranges 
from a minimum of 14 per cent to a maximum of 34 per cent. In other words, 
on the basis of photo interpretation alone, without field checking and accom 
panying map corrections, of the 493 areas classified as R it can be expected that 
error in designation will range from a minimum of 69 to a maximum of 168. 
To analyze the data further, Table V indicates the nature of the errors within 
each soil type. Errors in R turned out to be mainly BG with some B and a little 
G. The range of these errors are also calculated by use of the binomial theorem. 
Although 15 per cent of the areas designated as R by photo interpretation actu 
ally were BG by field sampling, in the photo interpretation of the entire quad 
rangle, designations of R can be expected to be BG ranging from a minimum of 
8 per cent to a maximum of 27 per cent of the time. 
The data represent only a comparison of office study designation of soil 
types by photo interpretation with actual field sampling. It should be stated 
here that Tables II, IV and V do not apply to the finished map of the Bangor 
Quadrangle as all errors observed in field work, and extending beyond the range 
of these data, were eliminated. 
In the field checking of the boundary lines of the finished map, only two 
Table V 
Photo Interpretation Errors Based on Field Sampling and Expected Range of 
Error at 19:1 Odds within Soil Types, Bangor Quadrangle, Maine 
Per Cent Misclassified within a Soil Type and Expected Range of Error at 19:1 Odds 
Soil 
R 
Error 
BG 
Error 
B 
Error 
G 
Error 
F 
Error 
s 
Error 
P 
Error 
Type* 
% 
% 
% 
% 
% 
% 
% 
% 
% 
% 
% 
% 
% 
% 
R 
32 
25-48 
10 
5-19 
2 
r— 
O 
BG 
15 
8-27 
3 
1-10 
B 
4 
1-12 
4 
1-12 
4 
0-21 
16 
9-24 
4 
0-14 
G 
1 
0- 8 
3 
0-10 
4 
1-12 
4 
1-10 
F 
10 
5-11 
19 
7-41 
2 
0-11 
S 
2 
O 
14 
6-32 
P 
20 
12-36 
Classification by field sampling.