[STATSGRASS] working with lat/long data in R+gstat

[Edzer J. Pebesma]

Carlos "Guâno" Grohmann wrote:
> Can I work with gstat with lat/long data? 
Ehm, no/yes. If you wait for a few days to get gstat version 0.9-35 
(just uploaded to CRAN), it does use great circle distances for distance 
evaluations if data are longlat. (i.e., they evaluate FALSE when passed 
to is.projected()). Make sure that for e.g. kriging you use a variogram 
model that is positive definite on the sphere; gstat does not check 
this. It seems that the exponentional model should work. Be aware that 
this is a mostly untested domain, for gstat at least. (You may want to 
look at package fields as an alternative).
> anyway I can import a
> GeoTiff into R as a dataframe without projection?
>
I don't know. I think rgdal will import it as a SpatialGridDataFrame, 
and I don't know if it retains the projection information in the GeoTIFF 
correctly. You may need to specify it yourself after importing.
--
Edzer
> tks
>
>
> Carlos
>