I have the "processing" toolbox installed on QGIS2 and it would appear to give me access to the SAGA variogram tools and and kriging tools. What I am missing and what I can't find via Google either, is some sort of help on how to use these packages.

The variogram tool dumps out a csv file containing what appears to be an experimental variogram for multiple directions plus covariance etc. The kriging tool has stumped me, what is a saga grid and why if I create one (which seems for all the world to be a tiff) won't the kriging tool find it? It would appear that I can specify the nugget and sill but as the variogram tool isn't overly helpful (at least as far as I can tell without any help files) then I can't know what values to use.

The SAGA site has a users guide but for most tools it seems to do nothing more than list their existence. I have also found a presentation of slides showing SAGA in use but as the windows in native SAGA don't match the QGIS implementations the slides aren't very helpful. Does anyone know of a good (or even not very good) documentation? Can anyone throw some light onto this?

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