[GRASS-user] grass-user Digest, Vol 79, Issue 7

[Patrick S.]

Hi Paulo,

I don't know anything about r.series and it's output, so please forward 
any results. But my approach would be to use R through the spgrass6 
package. This would be something as the commands below.

Inside grass-session, run:

R
setwd("~/mydata/01_Regressiondata")
memory.limit(2000)
library(spgrass6)      #install.packages()
library(car)

d.data1<-readRAST6(c("raster1"), cat=FALSE, ignore.stderr=TRUE)
d.data2<-readRAST6(c("raster2"), cat=FALSE, ignore.stderr=TRUE)
d.data3<-readRAST6(c("raster3"), cat=FALSE, ignore.stderr=TRUE)

#I expect you have to combine the datasets into one dataframe...
regdata<-data.frame(d.data1$raster1, d.data$raster2, d.data$raster3)

mod1<-lm(data3~data2+data1, data=reg_data)

summary(mod1)

q()
n



Hope that helps,

Patrick



On 11/06/2012 09:00 PM, grass-user-request at lists.osgeo.org wrote:
> Message: 2
> Date: Tue, 6 Nov 2012 09:55:02 +0100
> From: Paulo van Breugel<p.vanbreugel at gmail.com>
> To: GRASS users email list<grass-user at lists.osgeo.org>
> Subject: [GRASS-user] Calculate p value for regression slope in
> 	r.series
> Message-ID:
> 	<CAGrkfcJeZ-Ujwcp9FGCJBFnjKFNSS=cKgpj95paoZ4Gqm1dmmA at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi,
>
> I am using r.series to calculate linear regression slope, offset and
> coefficient of determination. But any idea how I can get the standard
> deviation t-value and p-value of the slope?
>
> Cheers,
>
> Paulo