[Soc] GRASS module for kriging - call for users [was: R-sig-Geo Digest, Vol 69, Issue 21]
On Sat, May 23, 2009 at 10:59 AM, Anne Ghisla Insubriae
<a.ghisla at studenti.uninsubria.it> wrote:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Ebrahim Jahanshiri a ?crit:
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