[R-sig-Geo] variogram estimation with adaptive sampling weights

[Paul Hiemstra]

Hi John,

I recently wrote a variogram fitting routine using the R function 
optim(). It works together with gstat. It is quite straightforward to 
write you own goal function for optim(), including the weights to use in 
the fitting. Send me an e-mail offlist if you need the code and some 
examples.

cheers,
Paul

Carson, John wrote:
> Dear r-sig-geostat members,
>
>  
>
> I have a spatial soil sampling design which will be used for a
> moderately large number of areas.  The first or primary stage is
> systematic.  Any primary locations observed to exceed one or more
> thresholds (it's a multivariable problem) will trigger (composite)
> sample collection in the 4 adjacent grid areas.  So the sampling is
> adaptive cluster sampling, and I use sampling weights for
> Horvitz-Thompson estimation (prop to 1/(prob of selection)).  I know
> that variograms estimated with this kind of clustered data can be
> biased.  I would like to directly incorporate sampling weights into the
> variogram estimation.  I have used gstat and geoR previously and don't
> see an easy way to use external weights.  
>
>  
>
> Does anyone know how to use external weights for variogram estimation in
> these packages?  Or are there other libraries that would work better?
>
>  
>
> Thanks in advance,
>
> John   
>
>  
>
> John H. Carson Jr., PhD
>
> Senior Statistician
>
> Applied Sciences & Engineering 
>
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>
> 16406 US Rte 224 East
>
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> Phone 419-425-6156
>
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>
> john.carson at shawgrp.com
>
>  
>
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>
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-- 
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone:  +3130 274 3113 Mon-Tue
Phone:  +3130 253 5773 Wed-Fri
http://intamap.geo.uu.nl/~paul