[R-sig-Geo] [Soc] GRASS module for kriging - call for users [was: R-sig-Geo Digest, Vol 69, Issue 21]

[Dylan Beaudette]

On Sat, May 23, 2009 at 10:59 AM, Anne Ghisla Insubriae
<a.ghisla at studenti.uninsubria.it> wrote:
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> Ebrahim Jahanshiri a écrit:
>> Dear Anne,
>
> Ebrahim,
>
>> Thanks for the enquiry. I think we should have done this long before. I
>> havent done any geostatistics with GRASS but I did alot in ArcGIS and also
>> in R (variography). I have to tell you that ArcGIS is for those who want to
>> have a surface only by just clicking on "finish" button trought its
>> powerfull interface. That is, it does not provide a good scientific
>> backgroud for you to check the procedure. for example how it fitted the
>> variogram model or how exactly it does the "validation". That is why the
>> "Geostatistical package" objects or classes are not available for the
>> programmers to program with (there is a kriging in "Spatial analyst" package
>> though that its object is programmable and I personally did some with it.
>> but it lacks the variogram modeling). I think they are still working on it.
>> In short I dont recommend ArcGIS for the so called scientific kriging.
>
> I was afraid of this. Therefore I guess an interface with too many
> mandatory options would be considered overcomplicated.
> There should be as more options as needed for a flexible calculations,
> and also proper defaults to clik on Ok and get an acceptable result.
> What do you think about this solution?
>
>> In
>> the other hand R is very powerfull in that it gives you freedom to do your
>> own style through coding. I worked with "GeoR" pakcage and it is pretty nice
>> both in terms of variography and kriging. There are other package like
>> "Gstat" that I havent worked with but have good qualities. GeoR implements
>> the so called "model based geostatistics" which is the application of
>> bayesian statististics to the geostistics I guess and it is quite new.
>
> I'm presently having a look at both geoR and gstat, and also the wrapper
> package automap.
> I guess that the first users of the new module would be already familiar
> with R and GRASS, so their feedback about most used functions is very
> important.
>

Hi. It is alway nice to see people working GRASS SoC projects, thank you!

I would just add-- I think that all efforts to build onto existing
libraries would be a good thing. That is to say, try and work with
GRASS-R-gstat: this is by far one of the best implementations of
geostatistics available. Paul's automap would be another likely
candidate .

The real problem with a single GRASS module for 'kriging' is that the
operation requires careful thought and familiarity with the data-- not
really something that can be easily generalized to the conceptual
basis of a single GRASS module. Perhaps asking Edzer about room for
user-interface improvements in the gstat code would yield some good
starting points.

Cheers,
Dylan