R help - Jul 2008 - kriging problem(?)

Hei,
I have two spatial datasets Sa and Sb, both with lat-lon coordinates and
from same geographic area, but from different localities within the area
(independent samples). Sa is biotoc data, Sb is some environmental
parameter (fertility). I 'know' that Sb affects Sa, but wonder on which
scale. I tried different interpolations by creating different grids of Sb
(e.g. 20x20 and 100x100 points using 'interp' ...) and found that a more
coarse grid did a better job in predicting Sa than a high resolution grid.
However, I wonder if there aren't more elegant ways, e.g. using kriging.
Just to avoid misunderstandings: I do not just want to get a spatial grid
of Sa and Sb, but I want to find on which Scale Sb affects Sa.
cheers,
Robert,


 Robert Ptacnik
 Norwegian Institute for Water Research (NIVA)
 Gaustadall?en 21
 NO-0349 Oslo
 FON +47 982 277 81
 FAX +47 221 852 00



----------------------------------------------------------------------------------------------------------------------
NIVAs hovedkontor har flyttet til nye lokaler i CIENS - Forskningssenter
for milj? og samfunn; Gaustadall?en 21, 0349 Oslo. Meld deg p? v?rt
nyhetsbrev p? www.niva.no).

Hi Robert,

A package I use for spatial statistics is gstat. It supports a method 
called co-kriging that seems to fit your needs. To get a good overview 
of the spatial capabilities of R a good place to start is the Spatial 
Task View (http://cran.r-project.org/web/views/Spatial.html). If you 
have more geo type questions the r-sig-geo list is a better forum 
(https://www.stat.math.ethz.ch/mailman/listinfo/R-SIG-Geo/).

cheers
Paul

robert.ptacnik at niva.no wrote:
> Hei,
> I have two spatial datasets Sa and Sb, both with lat-lon coordinates and
> from same geographic area, but from different localities within the area
> (independent samples). Sa is biotoc data, Sb is some environmental
> parameter (fertility). I 'know' that Sb affects Sa, but wonder on
which
> scale. I tried different interpolations by creating different grids of Sb
> (e.g. 20x20 and 100x100 points using 'interp' ...) and found that a
more
> coarse grid did a better job in predicting Sa than a high resolution grid.
> However, I wonder if there aren't more elegant ways, e.g. using
kriging.
> Just to avoid misunderstandings: I do not just want to get a spatial grid
> of Sa and Sb, but I want to find on which Scale Sb affects Sa.
> cheers,
> Robert,
>
>
>  Robert Ptacnik
>  Norwegian Institute for Water Research (NIVA)
>  Gaustadall?en 21
>  NO-0349 Oslo
>  FON +47 982 277 81
>  FAX +47 221 852 00
>
>
>
>
----------------------------------------------------------------------------------------------------------------------
> NIVAs hovedkontor har flyttet til nye lokaler i CIENS - Forskningssenter
> for milj? og samfunn; Gaustadall?en 21, 0349 Oslo. Meld deg p? v?rt
> nyhetsbrev p? www.niva.no).
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>   

-- 
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone: 	+31302535773
Fax:	+31302531145
http://intamap.geo.uu.nl/~paul