[STATSGRASS] Another problem with kriging (gstat)

[Jarek Jasiewicz]

Edzer J. Pebesma napisał(a):
> Jarek,
>
> Eight of your data are collocated:
>
> > zerodist(rf)
>     [,1] [,2]
> [1,]   46   47
> [2,]  136  142
> [3,]  145  147
> [4,]  150  152
> [5,]  200  201
> [6,]  213  214
> [7,]  328  333
> [8,]  332  334
>
> Removing them solves the problem. Try for example:
>
> krig=krige(cs~1, loc=rf[-zerodist(rf)[,1],], newdata=sg, model=frfit)
> spplot(krig[1],col.regions=bpy.colors())
>
> in which case you (arbitrarily) remove the first of each colocated pair.
> -- 
> Edzer
>
> Jarek Jasiewicz wrote:
>> Hi
>> It is outside statgrass because of attachment
>>
>> here are data and what I did (only simple model, without anisotropy 
>> spherical variogram etc) but I tested it on other variograms and with 
>> anisotropy, distance and so on, as well
>>
>>
>> first data:
>> rf  - with two slots: l (lenght) and cs (cosine) of the feature
>> sg - spatial grid dataframe on witch I try to do prediction
>>
>> first variogram:
>>
>> vr=variogram(cs~1, locations=rf)
>>
>> next fitting
>> frfit=fit.variogram(vr, vgm(1650, "Sph", 7000, 11000))
>>
>> and the last kriging
>> krig=krige(cs~1, loc=rf, newdata=sg, model=vrfit)
>>
>> after imaging
>> image(krig) the artefact will be visible well
>>
>> by the way: I aware that that data are not well suitable for kriging
>>
>> regards
>> Jarek Jasiewicz
thanks a lot

Jarek