[R-sig-Geo] passing 'cutoff' to the 'autoKrige' function ('automap' package)

[Paul Hiemstra]

On 03/28/2011 10:47 AM, Mauricio Zambrano wrote:
> 2011/3/26 Paul Hiemstra<p.hiemstra at geo.uu.nl>:
>    
>> Hi,
>>
>> The miscFitOptions parameter does not include the 'variogram' paramters. I
>> will look into adding them, together with the option to set the boundaries
>> manually. However, autofitVariogram at this stage defines a fixed set of
>> boundaries, so I'm not sure if the parameters you mention will resort any
>> effect even when passing them on. An option at this stage would be to use
>> the normal krige function combined with autofitVariogram. autofitVariogram
>> passes on parameters to variogram() using the ... .
>>
>> Could you create a new issue in the bitbucket.org account which stores
>> automap [1]? This way I can keep track of the issues that need to be fixed
>> for autofitVariogram.
>>      
> Thanks Paul for your answer.
>
> I created the issue in bitbucket.org, as an 'enhancement', not a bug.
>
> If you manage to include 'cutoff' and other  'variogram' paramters
> into the 'autofitVariogram' function, a way to use its value could be
> (after the definition of the 'scale_number'):
>
>
>    

Thanks for creating the issue, I'm not sure when I'll come round to 
fixing the issue though ;). I'll probably fix the problem by giving the 
user the freedom to change all inputs to variogram(), including 
boundaries. But I'll figure that out later.

>      scale_number = (0.35 * sqrt((max(x) - min(x))^2 + (max(y) -
>          min(y))^2)/100)
>      if (!is.na(cutoff))
>        scale_number<- min(scale_number, cutoff/100)
>      boundaries = c(2, 4, 6, 9, 12, 15, 25, 35, 50, 65, 80, 100) * scale_number
>
>
> Do you think it may work ?
>    

Could be an option.

cheers,
Paul
> In the mean time the combination of 'autofitVariogram' with 'krige'
> that you mention is a nice way to overcome the issue with cutoff.
>
> Thanks again for such a useful package.
>
> Cheers,
>
> Mauricio
>
>    


-- 
Paul Hiemstra, MSc
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone:  +3130 253 5773
http://intamap.geo.uu.nl/~paul
http://nl.linkedin.com/pub/paul-hiemstra/20/30b/770

currently @ KNMI
paul.hiemstra_AT_knmi.nl