2009/11/17 Edzer Pebesma edzer.pebe...@uni-muenster.de:
I just want to point out that krige has no problem with constant
observations, as long as it is provided with a valid (i.e. semi negative
definite, or something like that) variogram model.
Thanks for make this point clear.
The problem
Edzer Pebesma wrote:
My guess is that from constant data, the (co)variance is constant and
zero, so the covariance matrix cannot be decomposed (hence: LDLfactor
errors).
Is this a case that autokrige should catch?
I added a check in autoKrige. The output for the example below is now:
Thank you Edzer for giving a hint about the meaning of the 'LDLfactor'
error, and thank you Paul for adding a check to the 'autoKrige'
function.
Kind regards,
Mauricio
--
Ph.D. Candidate,
University of Trento
Dept. of Civil and Env. Engineering
: Tuesday, November 17, 2009 9:53 AM
To: Edzer Pebesma
Cc: r-sig-geo
Subject: Re: [R-sig-Geo] 'LDLfactor' error in 'krige' function
Edzer Pebesma wrote:
My guess is that from constant data, the (co)variance is constant and
zero, so the covariance matrix cannot be decomposed (hence: LDLfactor
Subject: Re: [R-sig-Geo] 'LDLfactor' error in 'krige' function
Edzer Pebesma wrote:
My guess is that from constant data, the (co)variance is constant and
zero, so the covariance matrix cannot be decomposed (hence: LDLfactor
errors).
Is this a case that autokrige should catch?
I added
://home.medewerker.uva.nl/t.hengl/
-Original Message-
From: r-sig-geo-boun...@stat.math.ethz.ch
[mailto:r-sig-geo-boun...@stat.math.ethz.ch] On Behalf
Of Paul Hiemstra
Sent: Tuesday, November 17, 2009 9:53 AM
To: Edzer Pebesma
Cc: r-sig-geo
Subject: Re: [R-sig-Geo] 'LDLfactor' error in 'krige
I just want to point out that krige has no problem with constant
observations, as long as it is provided with a valid (i.e. semi negative
definite, or something like that) variogram model. The problem is to
automatically fit such a function from data that are constant, as they
have zero
To: Tomislav Hengl
Cc: 'r-sig-geo'
Subject: Re: [R-sig-Geo] 'LDLfactor' error in 'krige' function
Tom, you can already do this:
library(gstat)
data(meuse)
coordinates(meuse)=~x+y
data(meuse.grid)
gridded(meuse.grid)=~x+y
meuse=meuse[c(1,1:155),] # replicate first observation
pr1 = predict(zinc
Dear List,
During some OK interpolations of daily precipitation, with the
'automap' library, I got the following error:
[using ordinary kriging]
chfactor.c, line 130: singular matrix in function LDLfactor()
Error en predict.gstat(g, newdata = newdata, block = block, nsim = nsim, :
LDLfactor
My guess is that from constant data, the (co)variance is constant and
zero, so the covariance matrix cannot be decomposed (hence: LDLfactor
errors).
Is this a case that autokrige should catch?
--
Edzer
Mauricio Zambrano wrote:
Dear List,
During some OK interpolations of daily precipitation,
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