Dear All, I have some problem in ST modeling using gstat. my program is : library(gstat) data<-read.table("cancer.txt",header=TRUE) value<-runif(105) sp = cbind(data$x,data$y) row.names(sp) = paste("point", 1:nrow(sp), sep="") sp = SpatialPoints(sp) time = as.POSIXct("2003-01-01")+360*(0:6) time mydata = data.frame(length(sp)*length(time),value) IDs = paste("ID",1:length(mydata)) stfdf = STFDF(sp, time, mydata) vv<-variogramST(value~1,stfdf,tlags = 1:10,cutoff=300000, width =30000/20) plot(vv,map=T) library(lattice) wireframe(gamma~spacelag*timelag+1, vv, drape=F,col.regions=bpy.colors)
Error: NAs are not allowed ........ How can I solve this problem. I use blow program to fit ST variogram function ExpVgmMetric = function(x, s, t, nugget = 0) { h = sqrt(s^2 + (x[3] * as.numeric(t))^2) ifelse(h == 0, 0, nugget + x[1] * (1 - exp(-h / x[2]))) } ExpFitFn = function(x, gfn, v, trace = FALSE, ...) { mod = gfn(x, v$spacelag, v$timelag, ...) resid = v$gamma - mod if (trace) print(c(x, MSE = mean(resid^2))) mean(resid^2) } pars.M = optim(c(sill = 5, range = 169, anis = 0), ExpFitFn, gfn = ExpVgmMetric, v = vv, nugget = 0) pars.M$par vv$model = ExpVgmMetric(pars.M$par, vv$spacelag, vv$timelag, nugget = 0) plot(vv) but it's sill is negative and in plot part model only has a single value and dose not change by changing spatial and temporal lags. Best, Saman. -- Saman Monfared Msc, Department of Statistics, Shiraz University, Shiraz 71454, Iran Email: samanmonfar...@gmail.com Tel: +98 917 5305167 _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo