[R-sig-Geo] Universal kriging with geoR

[GEMA FERNANDEZ-AVILES CALDERON]

Dear list,

I have a computational error and I can not found the solution...

I would like to perform an Universal Kriging with geoR. I have a geodata object: log(price), long, lat and pollution, but 'krige.conv' and 'ksline' functions give me the same error: system is computationally singular.

Any ideas will be appreciated.

Thanks in advance,
Gema

PS: I can send you the data to run the code


############################################################################

# read the data and create a geodata object
attach(Datos)
bordes.munimadrid=read.table("MuniMadrid.txt")
coord=cbind(long,lat)
uk.vivi<-cbind(coord , log(Datos$precio.house.x), Mal_olor )
obj.uk.vivi<-as.geodata(obj=uk.vivi, coords.col = 1:2, data.col = 3,
              covar.col = 4 ,covar.names = "Pollution" )
summary(obj.uk.vivi)

#Number of data points: 300
#
#Coordinates summary
#      long     lat
#min 433426 4466197
#max 451184 4484681
#
#Distance summary
#     min      max
#   19.18 20836.71
#
#Data summary
#   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
#   6.91    7.94    8.19    8.16    8.43    9.28
#
#Covariates summary
#    Mal_olor
# Min.   :0.080
# 1st Qu.:0.210
# Median :0.260
# Mean   :0.281
# 3rd Qu.:0.330
# Max.   :0.720


## I woulk like to use this spatial trend but UK doesn't run
sp.tren.rp=trend.spatial("1st", obj.uk.vivi, add=~Mal_olor)

# Universal kriging with geoR() first option
loci <- expand.grid(seq(424854, 456141, l = 101), seq(4462788, 4499622, l = 101))
UK.krig.viviendas <- krige.conv(obj.uk.vivi, loc = loci, borders = bordes.munimadrid,
              krige = krige.control(type.krige = "ok", cov.model = "gau",
              cov.pars = c(0.06, 3000), nug = 0.05, trend.l = "1st", trend.d ="1st") )

krige.conv: results will be returned only for prediction locations inside the borders
krige.conv: model with mean given by a 1st order polynomial on the coordinates
Error in solve.default(ttivtt, crossprod(ivtt, as.vector(data))) :
  sistema es computacionalmente singular: número de condición recíproco = 6.8379e-20


# Universal kriging with geoR() second option
uk.2= ksline(obj.uk.vivi, coords = obj.uk.vivi$coords, data = obj.uk.vivi$data,
       loc = loci, borders = bordes.munimadrid,
       cov.model = "gau",  cov.pars=c(0.06, 3000), nug = 0.05,
       lambda = 1, m0 = "kt", nwin = "full",
       trend = 1, d = 2 )

ksline: results will be returned only for prediction locations inside the borders
Error in solve.default(crossprod(xmat, iv) %*% xmat) :
sistema es computacionalmente singular: número de condición recíproco = 6.8379e-20

############################################################################


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