[R-sig-Geo] Problem with semi variance estimates in space time variogram (gstat)

[Rawlins, Barry G.]

Hello

The variograms function in gstat is returning semi-variance estimates which appear to be two orders of magnitude lower than what I expect from calculating the variance of the data in the attached space time object created with the STFDF function:

library(gstat)
library(spacetime)
breaks<-seq(0.5,12.5,1)
var_all <- variogram(VMC~1,sp_time_var, bounds=breaks, cutoff = 12.5) # VMC is the numeric data to calculate a sp-time varigram
plot(var_all) # note the low values ranges on the scale <0.15
var(sp_time_var at data$VMC) # variance is 11.5

So I would expect the variance in the upper part of the graph to approach a value around 11.

Have I mis-specified the variogram function? I know from gstat that one had to specify a gstat object, but here I thought specifying the spacetime object was the right way to proceed and that VMC~1 was the correct syntax?

Any advice much appreciated.
Barry



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