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topography and topography plus electrical conductivity data. Separation of WD and MWD classes
was less successful due to the above-mentioned insignificant differences between slope and deep
EC values corresponding to WD and MWD drainage classes. Discriminant analysis with topog-
raphy and EC slightly improved the estimation accuracy comparing with topography only due to
better separation of WD and MWD drainage classes.
Cross-validation results of indicator kriging were not as accurate as those from discriminant
analysis. Indicator kriging correctly estimated drainage classes at only 56 percent of the sites com-
paring with more than 60 percent of correct estimations from discriminant analysis. Better results
were obtained when information on spatial variability of drainage class data was supplemented by
the topographical data in the cokriging procedure. Indicator cokriging with slope and distance to
drainageway produced the most accurate drainage class prediction comparing with the other meth-
ods (Table 17.2).
The most substantial difference between discriminant analysis and kriging and cokriging for
creating maps pertains to the fact that kriging and cokriging procedures are exact estimators, and
tAble 17.2
number of Correctly and Incorrectly Classified Wd,
MWd, and SWpd/pd drainage Classes and the total
percent of Correctly Identified Classes from discriminant
Analysis, Indicator kriging, and Indicator Cokriging;
values in parentheses Are percentages of Correctly
estimated Sites for each drainage Class
Classified as
true drain
Class
Wd
MWd
SWpd/pd
total % Correct
discriminant analysis with topographical variables
(significant from stepwise procedure are slope and distance to drain)
WD
33 (69%)
14
1
MWD
19
17 (45%)
2
61.7
SWPD/PD
1
4
16 (76%)
discriminant analysis with topographical and eC variables
(significant from stepwise procedure are eC deep and distance to drain)
WD
36 (75%)
10
2
MWD
18
17 (45%)
3
63.6
SWPD/PD
1
5
15 (71%)
Indicator kriging
WD
31 (65%)
16
1
MWD
18
15 (39%)
5
56.1
SWPD/PD
3
4
14 (67%)
Indicator cokriging with slope and distance to drain
WD
47 (98%)
1
0
MWD
26
10 (26%)
2
65.4
SWPD/PD
7
1
13 (62%)
Indicator cokriging with eC deep and distance to drain
WD
36 (75%)
9
3
MWD
21
8 (21%)
9
57.9
SWPD/PD
3
0
18 (86%)
