Hi All, I want to perform ordinary kriging on a series of air pollution values, but am getting the error
/> IL.Jul7.ok<-krige(Arithmetic.Mean~1, IL.Jul7, model=ILvgm.jul7, newdata=IL2.map) [using ordinary kriging] "chfactor.c", line 131: singular matrix in function LDLfactor() Error in predict.gstat(g, newdata = newdata, block = block, nsim = nsim, : LDLfactor/ I know that this error is typically caused by either duplicate points or a variogram without a nugget effect. However, I have neither (see code below). I also have set the same projection for points and prediction grid, plus ran an IDW successfully /[CRS("+proj=longlat +ellps=GRS80 +datum=NAD83 +no_defs")] / /> ILvgm.jul7 model psill range 1 Nug 1.537923 0.000 2 Sph 53.045879 266.323 > zerodist(IL.Jul7) [,1] [,2] > summary(IL.Jul7@data$Arithmetic.Mean) Min. 1st Qu. Median Mean 3rd Qu. Max. 13.50 17.60 21.95 22.82 27.83 32.10 / Any thoughts as to what might be causing this problem? Sorry for not providing a reproducible example, as I can't reproduce it and have run similar code without problems on other data. Thanks for the suggestions. Jesse ----- -------------------------------------------------------- Jesse D Berman, PhD Johns Hopkins Bloomberg School of Public Health Department of Environmental Health Sciences Post-Doc -- View this message in context: http://r-sig-geo.2731867.n2.nabble.com/Singular-Matrix-Error-tp7584203.html Sent from the R-sig-geo mailing list archive at Nabble.com. _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo