NAME¶
r.kappa - Calculate error matrix and kappa parameter for accuracy
assessment of classification result.
KEYWORDS¶
raster, statistics
SYNOPSIS¶
r.kappa
r.kappa help
r.kappa [-
wqh]
classification=
name
reference=
name [
output=
name]
[
title=
string] [--
verbose] [--
quiet]
Flags:¶
- -w
-
Wide report
132 columns (default: 80)
- -q
-
Quiet
- -h
-
No header in the report
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- classification=name
-
Name of raster map containing classification result
- reference=name
-
Name of raster map containing reference classes
- output=name
-
Name for output file containing error matrix and kappa
- title=string
-
Title for error matrix and kappa
Default: ACCURACY ASSESSMENT
DESCRIPTION¶
r.kappa tabulates the error matrix of classification result by crossing
classified map layer with respect to reference map layer. Both overall
kappa (accompanied by its
variance) and conditional
kappa
values are calculated. This analysis program respects the current geographic
region and mask settings.
r.kappa calculates the error matrix of the two map layers and prepares
the table from which the report is to be created.
kappa values for
overall and each classes are computed along with their variances. Also percent
of commission and ommission error, total correct classified result by pixel
counts, total area in pixel counts and percentage of overall correctly
classified pixels are tabulated.
The report will be write to an output file which is in plain text format and
named by user at prompt of running the program.
The body of the report is arranged in panels. The classified result map layer
categories is arranged along the vertical axis of the table, while the
reference map layer categories along the horizontal axis. Each panel has a
maximum of 5 categories (9 if wide format) across the top. In addition, the
last column of the last panel reflects a cross total of each column for each
row. All of the categories of the map layer arranged along the vertical axis,
i.e., the reference map layer, are included in each panel. There is a total at
the bottom of each column representing the sum of all the rows in that column.
NOTES¶
It is recommended to reclassify categories of classified result map layer into a
more manageable number before running
r.kappa on the classified raster
map layer. Because
r.kappa calculates and then reports information for
each and every category.
NA's in output file mean non-applicable in case
MASK exists.
EXAMPLE¶
Example for North Carolina sample dataset:
g.region rast=landclass96 -p
r.kappa -w classification=landuse96_28m reference=landclass96
Verification of classified LANDSAT scene against training areas:
r.kappa -w classification=lsat7_2002_classes reference=training
SEE ALSO¶
g.region,
r.category,
r.mask,
r.reclass,
r.report,
r.stats
AUTHOR¶
Tao Wen, University of Illinois at Urbana-Champaign, Illinois
Last changed: $Date: 2014-05-05 21:40:05 +0200 (Mon, 05 May 2014) $
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