1. Spatial-temporal modeling

2. Basics in Gaussian process

3. Covariance function and variogram

4. Kriging

Code: Introduction to “fields” package

Ozone data set, day 16

# Quilt plot
data(ozone2)
# plot 16 day of ozone data set
quilt.plot(ozone2$lon.lat, ozone2$y[16,])
US(add=TRUE, col="grey", lwd=2)

Compute variogram for the midwest ozone field

good<- !is.na(ozone2$y[16,])
x<- ozone2$lon.lat[good,] 
y<- ozone2$y[16,good]

## variogram plots
par(mfrow=c(1,2))
look<-vgram(x,y, N=15, lon.lat=TRUE)
plot(look, pch=19)

## or some boxplot bin summaries
brk<- seq(0, 250,, (25 + 1) ) # will give 25 bins.
boxplotVGram(look, breaks=brk, plot.args=list(type="o"))
plot(look, add=TRUE, breaks=brk, col=4)