[R-sig-Geo] (residual) variograms and trend adjustment
trichter at uni-bremen.de
Tue Sep 16 15:16:27 CEST 2014
I just had a talk with a reviewer of my thesis. He strongly criticized
the way i was interpreting variograms without previous trend adjustment.
In fact, i am following the route in "Applied Spatial Data Analysis with
R", chapter 8. On page 218, i think its stated the basic assumption of
the variogram is that the variance of the random function Z is solely
based on the separation distances. However, it was said that variograms
should only display the residuals of Z (y=mx+b+e), never the complete
term. I first should identify non-spatial trends in the data.
I find this very difficult without knowing the autocorrelation of a
dataset. So, the real question is, what comes first: Autocorrelation or
pairwise correlations of observations?
Starting with page 230 of the same book, there is a tutorial for
residual variogramming, but i think this assumes that i already know the
functions i want to test, or?
How would you deal with this remark?
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