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NAME

d.correlate - Prints a graph of the correlation between data layers (in pairs).

KEYWORDS

display, diagram

SYNOPSIS

d.correlate
d.correlate help
d.correlate [-t] layer1=string layer2=string [layer3=string] [layer4=string] [--verbose] [--quiet]

Flags:

-t
Draw a trend line
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

layer1=string
raster input map
layer2=string
raster input map
layer3=string
raster input map
layer4=string
raster input map

DESCRIPTION

d.correlate is a shell (sh(1)) script that graphically displays the results of an r.stats run on two raster map layers. This shell script is useful for highlighting the correlation (or lack of it) among data layers (scattergram).

The results are displayed in the active display frame on the user's graphics monitor. d.correlate erases the active frame before displaying results.

OPTIONS

Parameters:

layer1 layer2 [layer3 [layer4]]
The names of from two to four existing raster map layers to be included in the correlation.

NOTES

This is a shell script that uses r.stats and the UNIX awk command to calculate the correlation among data layers, and uses d.text and d.graph to display the results.

If three or four map layers are specified, the correlation among each combination of two data layers is displayed.

EXAMPLE

North Carolina sample dataset:
d.correlate -t layer1=lsat7_2002_10 layer2=lsat7_2002_20

FILES

This program is simply a shell script. Users are encouraged to make their own shell script programs using similar techniques. See $GISBASE/scripts/d.correlate.

SEE ALSO

d.text, d.graph, r.coin, r.regression.line, r.stats

AUTHOR

Michael Shapiro, U.S.Army Construction Engineering Research Laboratory

Rewritten to GRASS 6 (from csh to sh) by Markus Neteler
Trend line and model fix option added by Hamish Bowman

Last changed: $Date: 2010-06-08 16:58:08 -0700 (Tue, 08 Jun 2010) $


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