I would like to make some kriging in a belgian territory.
I got a data set called
clean.donnees.Ni after removing outliers and
I first tried simply with this, but got this warning as result :
Ni.krig <- krige(formula = Ni~1, data = clean.donnees.Ni, locations = ~x+y, newdata = krig.grid, model = Ni.vg.fit) Warnings : Covariance matrix singular at location [50686, 156893,0]: skipping
I found on other topics that I probably got points at the same location. (R gstat krige() - Covariance matrix singular at location [5.88,47.4,0]: skipping)
They advice to use this to remove points on the same location:
clean.donnees.Ni <- clean.donnees.Ni[-zerodist(clean.donnees.Ni)[,1],]
When I did this, I finally thought I could make krige() work, but instead it nows returns me this error :
Ni.krig <- krige(formula = Ni~1, data = clean.donnees.Ni, locations = ~x+y, newdata = krig.grid, model = Ni.vg.fit) Error in `coordinates<-`(`*tmp*`, value = locations) : setting coordinates cannot be done on Spatial objects, where they have already been set
Because I had to transform
clean.donnees.Ni in a SpatialPointsDataFrame, locations can't read ~x+y anymore.
Does anyone knows how to makes kriging work ?