asbio (version 0.2-1)

Kappa: Calculates kappa statistic and other classification error statistics

Description

The kappa statistic, along with user and producer error rates are conventionally used in the remote sensing to describe the effectiveness of ground cover classifications. Since it simultaneously considers both errors of commission and omission, kappa can be considered a more conservative measure of classification accuracy than the percentage of correctly classified items.

Usage

Kappa(class1, reference)

Arguments

class1

A vector describing a classification of experimental units.

reference

A vector describing the "correct" classication of the experimental units in class1

Value

• Returns a list with 5 items
• ttl_agreement
  The percentage of correctly classified items.
• user_accuracy
  The user accuracy faor each category of the classification.
• producer_accuracy
  The producer accuracy for each category of the classification.
• table
  A two way contingency table comparing the user supplied classification versus the reference classification.

References

Jensen, J. R. (1996) Introductory digital imagery processing 2nd edition. Prentice-Hall.

Examples

reference<-c("hi","low","low","hi","low","med","med")
class1<-c("hi","hi","low","hi","med","med","med")
Kappa(class1,reference)