[R-sig-Geo] Spatio Temporal kriging in Gstat

[Dan Turenne]

My apologies, I accidentally sent an unfinished email, here is the complete version of my question


Hello R-Sig-Geo,


As part of my masters thesis I am attempting to use spatio-temporal regression kriging to make predictions with temperature data, and I was hoping that someone might be able to give some insight as to how the algorithms work in gstat.  My data consists of daily temperature observations from April 1 to July 31, 2000.  There are observations from 164 stations across these 122 days, however not all stations have observations on all days, making for a total of 19282 records.


I have tried to use an STSDF object but I have not had any success.  I created an sp object of length 164 with the station locations:


    sp = data.frame(long = stations$long, lat = stations$lat)

    coordinates(sp) = ~ long+lat


Then I created a vector of length 122 with the times the observations were recorded and a data vector of length 19282:


    beginDate = as.Date(2000/04/01)

    endDate = as.Date(2000/07/31)

    times = as.POSIXct(seq(beginDate,endDate,by="days"))


    data=data.frame(temps$residual)


And I also made an index detailing where observations are available, it looks like this with the first column representing spatial index and the second representing the time index


    1   1

    2   1

    3   1

    4   1


    st=STSDF(sp,time,data,index,endTime=delta(time))


however when I try to calculate the sample variogram I get the following error:


    sample.stVariogram=variogramST(residual~1,data=st, tunit="days", tlags=1:7, progress=TRUE)



   Error in apply(do.call(cbind, lapply(ret, function(x) x$np)), 1, sum,  :
   dim(X) must have a positive length
   In addition: There were 50 or more warnings (use warnings() to see the first 50)


All 50 of the errors are :


  In is.na(data[[as.character(as.list(formula)[[2]])]]) :
   is.na() applied to non-(list or vector) of type 'NULL'


Can anyone see what I am doing wrong or give me any pointers?  This error  is rather cryptic and I'm not quite sure what I'm doing wrong.  Any help would be appreciated.


Many Thanks,

Daniel Turenne

University of Manitoba


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