Fitting a STvariogram
Dear Alexandre,
currently, the parameter "anis" in one of the building blocks of a
spatio-temporal variogram model is not supported. The spatio-temporal
anisotropy (e.g. in a metric model) is part of the spatio-temporal
variogram model definition ("stAni"), see ?vgmST for available models
and parameter definitions.
We do not provide special plotting functions to fit the spatio-temporal
anisotropy. However, the demo(stkrige) will show levelplots for sample
and model variograms and bring up an interactive "lollipop3d"-plot
(based on the rgl package) to visually judge the overall variogram fit.
The function fit.StVariogram will minimize (using optim) all parameters
(incl. stAni where part of the model) in terms of the residuals between
sample and model variogram.
I hope this helps. Best wishes
Ben
On 25.02.2013 11:34, alexandre.champendal at unil.ch wrote:
Hello, I am working with spacetime data of pollution (91 stations, 193 time). With the new release of gstat, i was able to compute a good sample variogram (thanks :-)).
You're welcome; it is always nice to see code being used.
But now I would like to now if there is a way to visualize our data set in order to be able to define a good Space-Time anisotropy !? I understand the variable we have to set: anis = c(p,q,r,s,t), but i am not able to find a good way to find the parameters. How can we do this? Thanks a lot. Alexandre
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
Benedikt Gr?ler ifgi - Institute for Geoinformatics University of Muenster http://ifgi.uni-muenster.de/graeler Phone: +49 251 83-33082 Mail: ben.graeler at uni-muenster.de