Calculate the Kappa coefficient of two classifications

Description

This function takes a contingency table as calculated with table or crosstab and computes the Kappa coefficient.

Usage

Kappa(tab)

Arguments

Value

Kappa coeffcient

Author(s)

Matthias Forkel <matthias.forkel@geo.tuwien.ac.at> [aut, cre]

References

Congalton, R.G. (1991): A review of assessing the accuracy of classifications of remotely sensed data. - Remote Sensing of Environment 1991, 37, 35-46.

See Also

CompareClassification, AccuracyAssessment, TrendClassification

Examples

# two classifications: 
a <- c(1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 5, 1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 3, 3, 2, 2)
b <- c(1, 2, 1, 2, 2, 2, 3, 4, 2, 2, 5, 1, 2, 2, 2, 1, 2, 3, 4, 5, 5, 3, 3, 2, 2)

# calculate first a contingency table
tab <- table(a, b)

# calculate now the accuracy assessment
AccuracyAssessment(tab)

# calculate Kappa coeffcient
Kappa(tab)