[STATSGRASS] krigged dem lost detail

[Markus Neteler]

Carlos,

I didn't follow this thread in details (although very interesting).
There is cross validation for optimizing tension and smoothing,
did you make use of that (sorry, if already written...)?

I received a script from Jaro to automate the parametrization.
Let me know if you need it (maybe it should go into the Wiki,
so that you/others could document the procedure)

Markus

On Wed, Mar 15, 2006 at 07:16:11PM +1300, Hamish wrote:
> > I am comparing the results we get when re-interpolating a DEM to a
> > higher resolution. I did it with krigging (in R, with gstat) and with
> > RST. In the final result it looks like the krigged DEM has lost
> > detail, while the RST DEM kept those.
> > see it:
> > http://www.igc.usp.br/pessoais/guano/tempo/krigging.jpg
> > http://www.igc.usp.br/pessoais/guano/tempo/rst.jpg
> > 
> > I don't know why this happens, since they were interpolated wit the
> > same resolution, based on the same dataset.
> 
> 
> be careful you haven't added detail that isn't really there due to
> spline artifacts. Perhaps resample known DEM at lower resoution and then
> re-interpolate at original resolution to compare which does a better
> job recreating the original DEM?
> 
> r.resamp.rst
> 
> 
> 
> Hamish
> 
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-- 
Markus Neteler     <neteler itc it>       http://mpa.itc.it
ITC-irst -  Centro per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
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