Hi Gregoire
If I have understood the problem, the weird thing is that if there is
a strong correlation between data and residuals and your data show
continuity, the residuals should not present a pure nugget effect.
Sebastiano T.
At 12.59 30/01/2008, Gregoire Dubois wrote:
Dear list,
Having fit a variogram to a dataset (indoor radon measurements) and
applied cross-validations, I noticed the perfect negative
correlation (-0.95) between my kriging residuals and my input data.
This means that I am overestimating as much the low values as I am
underestimating the high values, something I am expecting since the
mean of the residuals -> 0, a property of kriging. Fine so far.
What I am puzzled about is of the possible reasons of getting such a
strong slope (close to -1) of the plot of my residuals against my input data?
This, I understand, highlights that I am doing a systematic error
somewhere which I want to avoid obviously. I thought I extracted
properly the spatially correlated component of my dataset (the
variogram of my residuals seems to show a pure nugget effect) but I
still can't find any reasonable explanation for the systematic errors.
Any hints? I must have missed something obvious here.
Many thanks for any feedback.
Best regards,
Gregoire
