1r.regression.line(1)          Grass User's Manual         r.regression.line(1)
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NAME

6       r.regression.line  - Calculates linear regression from two raster maps:
7       y = a + b*x
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KEYWORDS

10       raster, statistics
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SYNOPSIS

13       r.regression.line
14       r.regression.line help
15       r.regression.line   [-g]   map1=string   map2=string    [output=string]
16       [--verbose]  [--quiet]
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18   Flags:
19       -g
20           Print in shell script style
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22       --verbose
23           Verbose module output
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25       --quiet
26           Quiet module output
27
28   Parameters:
29       map1=string
30           Map for x coefficient
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32       map2=string
33           Map for y coefficient
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35       output=string
36           ASCII file for storing regression coefficients (output to screen if
37           file not specified).
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DESCRIPTION

40       r.regression.line Calculates linear regression from  two  raster  maps,
41       according  to  the  formula y = a + b*x, where x and y represent raster
42       maps.  Optionally saves regression coefficients to an ASCII file.   The
43       result  includes  the  following coefficients: offset/intercept (a) and
44       gain/slope (b), residuals (R), number of  elements  (N),  means  (medX,
45       medY),  standard  deviations (sdX, sdY), and the F test for testing the
46       significance of the regression model as a whole (F).
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EXAMPLE

49       Comparison of the old and the new DEM in Spearfish:
50       g.region rast=elevation.10m -p
51       r.regression.line map1=elevation.dem map2=elevation.10m
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54       Using the script style flag AND eval to make results available  in  the
55       shell:
56       g.region rast=elevation.10m -p
57       eval `r.regression.line -g map1=elevation.dem map2=elevation.10m`
58       echo $a
59       479.615
60       echo $b
61       0.645631
62       echo $R
63       0.804441
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AUTHOR

67       Dr. Agustin Lobo - alobo at ija.csic.es
68       Updated to GRASS 5.7 Michael Barton, Arizona State University
69       Script style output Markus Neteler
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71       Last changed: $Date: 2007-12-17 14:53:55 +0100 (Mon, 17 Dec 2007) $
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73       Full index
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75       © 2003-2008 GRASS Development Team
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79GRASS 6.3.0                                               r.regression.line(1)
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