490
Table 1. Comparison of new gopher mound counts obtained by photointerpretation
of 1:600 scale color infrared aerial photos with actual ground counts
of new pocket gopher mounds.
Item
Interpretation Results
PI-1
PI-2
PI-3
Mean
Ground Count (No.)
226
226
226
226
Photo Count (No.)
148
130
102
129
Omission Error (No.)
121
129
152
134
Omission Error (%)
53.5
57.1
67.2
59.3
Commission Error (No.)
43
41
28
37
Commission Error (%)
19
18.1
12.4
16.5
Total Error (No.)
164
170
180
171
Correct PI (No.)
105
97
74
92
Correct PI (%)
46.5
42.9
32.7
40.7
Table 2. Comparison of pocket gopher population estimates by ground mound
counts and photointerpreted mound counts using 1:600 scale color
infrared photography by three photointerpreters.
Plot
Ground population
estimate
Photointerpreted Population Estimate 1
PI-1
PI-2
PI-3
A
41
38
40
36
B
34
44
36
40
C
28
25
30
35
D
22
35
37
28
E
40
26
29
32
F
40
31
26
25
Mean
34
33
33
33
^-Adjusted for the difference between ground mound counts and photointerpreted
mound counts on a plot-by-plot basis.