NAME¶

d.correlate - Prints a graph of the correlation between raster maps (in pairs).

KEYWORDS¶

display, correlation, scatterplot

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 and calculate linear regression formula

--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. The layern parameters supply the names of 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¶

Compare LANDSAT-7 bands 2 and 3 in the North Carolina sample dataset, and over-plot a trend line:
g.region rast=lsat7_2002_20
d.correlate -t layer1=lsat7_2002_20 layer2=lsat7_2002_30 --verbose

SEE ALSO¶

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

AUTHORS¶

Michael Shapiro, U.S.Army Construction Engineering Research Laboratory Rewritten to GRASS 6 (from csh to sh) by Markus Neteler Linear regression model and trend line plotting by Hamish Bowman Last changed: $Date: 2013-09-22 09:51:30 +0200 (Sun, 22 Sep 2013) $ Full index © 2003-2014 GRASS Development Team