Table 2. Error matrix based on 626 Differential Global Positioning System (DGPS) locations for the validation of 13 peatland habitats classified using a maximum likelihood function method. Each of the 626 DGPS positions is compared to a reference zone of 3 x 3 pixels on the classified image. The bottom-right pixel of these reference zones corresponded to the DGPS validation location. Numbers represent, for each habitat type recognized in the field (columns), the percentage of pixels in the corresponding reference zones classified in each habitat class (rows). Diagonal entries indicate correct classification. The number of pixels considered on the classified image for all of the 626 DGPS positions is given in the second-to-last row. Some reference zones located near a peatland edge were less than 9 pixels (0.81 ha) in size, which explains why the number of pixels is not always a multiple of 9. Numbers in brackets correspond to the number of DGPS positions for each habitat class. Codes are defined in Table 1.

 
SprFor
Eric
Herb
TSedge
Spr
EriSpr
HerSpr
LarEri
EriLar
LarHer
HerLar
SprPool
LawnPool
SprFor
54
0
1
2
11
6
4
2
4
4
4
32
1
Eric
3
47
6
1
2
8
0
5
13
5
3
1
4
Herb
0
1
35
18
3
1
11
3
0
8
10
0
9
TSedge
2
8
14
43
3
2
8
1
2
12
7
2
28
Spr
18
2
2
6
47
10
16
0
2
7
3
8
10
EriSpr
3
20
3
6
11
48
5
2
7
1
5
0
3
HerSpr
3
3
9
6
16
8
43
3
6
9
8
0
5
LarEri
9
6
1
1
1
3
0
66
21
8
4
1
4
EriLar
1
7
0
0
1
4
0
9
40
6
5
0
0
LarHer
5
2
6
7
4
8
6
7
2
26
14
2
1
HerLar
0
4
23
9
2
1
4
4
3
11
35
0
8
SprPool
1
0
0
1
0
0
2
0
0
2
0
51
6
LawnPool
0
0
0
2
0
0
0
0
0
0
0
4
20
Number
of pixels
258
586
454
363
479
481
636
239
262
449
595
169
159
DGPS
locations
33
68
54
43
57
56
77
36
33
58
72
20
19