[GRASSLIST:9954] Re: R, kriging and grass6

[Vellinga, Olaf]

> If you like, we can iterate to a working example from passing 
> the vector points to R from GRASS, doing the modelling and 
> kriging predictions, and passing the prediction rasters back 
> to GRASS, but I'd like input from users to make the description sound.

As a novice to this topic (exactly, I'm right now trying to dig into
it), this would be a great idea.


Best regards,

Olaf Vellinga

--
Wageningen UR
Alterra
Centre for Water & Climate
Team Land-Atmosphere Interactions
Address: www.sense.nl/researchers/vellinga
Global Met-Pages: www.globalmetpages.net

 

> -----Original Message-----
> From: owner-GRASSLIST at baylor.edu 
> [mailto:owner-GRASSLIST at baylor.edu] On Behalf Of Roger Bivand
> Sent: maandag 23 januari 2006 13:15
> To: ivan marchesini
> Cc: grasslist-en
> Subject: [GRASSLIST:9953] Re: R, kriging and grass6
> 
> On Mon, 23 Jan 2006, ivan marchesini wrote:
> 
> > Hi to all...
> > we are triyng to use kriging using R and grass6, We have 
> seen a lot of 
> > documentation about R and GRASS5 but not so many about grass6...
> > the problem is that we are trying to do an interpolation using the 
> > functions gmeta6 and kriging...
> > if we are not wrong, the R library GRASS is developed for 
> grass5 and 
> > inside there is the function krige.G that use the location data 
> > acquired using the gmeta() function...
> > the problem is that we have found the gmeta6() function but not the
> > krige.G6 function and obvously the krige.G doesn't work using the 
> > location data of grass6 (obtained using gmeta6)
> > 
> > how can we simply solve this problem....
> 
> krige.G was a nasty hack, and should best be forgotten. The 
> direct route is to use the sp classes in R and implemented 
> for GRASS in spgrass6 - see GRASS News for the GRASS side and 
> R News for the R side, combined with a proper R geostats 
> package. Of those available, gstat is tightly bound to sp 
> classes, so as far as I know, the only bit that needs doing 
> by hand is to create a GridTopology object, or a SpatialGrid 
> object, from the data returned by gmeta6() to pass to the 
> kriging prediction function.
> 
> If you like, we can iterate to a working example from passing 
> the vector points to R from GRASS, doing the modelling and 
> kriging predictions, and passing the prediction rasters back 
> to GRASS, but I'd like input from users to make the description sound.
> 
> Best wishes,
> 
> Roger
> 
> > 
> > thank you
> > 
> > Ivan
> > 
> > 
> > 
> > 
> 
> --
> Roger Bivand
> Economic Geography Section, Department of Economics, 
> Norwegian School of Economics and Business Administration, 
> Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; 
> fax +47 55 95 95 43
> e-mail: Roger.Bivand at nhh.no
> 
> 
>