[R-sig-Geo] equations for cross variograms (Applied Spatial Data Analysis with R)
tom.gottfried at wzw.tum.de
Tue Dec 8 16:18:59 CET 2009
two questions about the equations on page 206 of the ASDAR book:
1) is it possible, that in the first one, there is "1/2" missing before the expression of the
expected value? I looked in some books and papers and it's always there.
2) is there any literature that could help me understand the second equation (for non-collocated
data). Mostly the pseudo-cross semivariance is mentioned for use with non-collocated data and is
expressed as half the variance of differences such as
gamma_ij(h)=1/2 Var[Z_i(x+h) - Z_j(x)]
Is this the same as what is expressed by the second equation on page 206 of the ASDAR book and thus
what is calculated by gstat::variogram?
Thank you very much!
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