agridat (version 1.12)

cleveland.soil: Soil resistivity in a field

Description

Soil resistivity in a field

Format

A data frame with 8641 observations on the following 5 variables.

northing

y ordinate

easting

x ordinate

resistivity

Soil resistivity, ohms

is.ns

Indicator of north/south track

track

Track number

Details

Resistivity is related to soil salinity.

Examples

# NOT RUN {
data(cleveland.soil)
dat <- cleveland.soil

# Similar to Cleveland fig 4.64
## require(latticeExtra)
## levelplot(resistivity ~ easting + northing, data = dat,
##           col.regions=RedGrayBlue,
##           panel=panel.levelplot.points,
##           aspect=2.4, xlab= "Easting (km)", ylab= "Northing (km)",
##           main="cleveland")

# 2D loess plot. Cleveland fig 4.68
sg1 <- expand.grid(easting = seq(.15, 1.410, by = .015),
                        northing = seq(.150, 3.645, by = .015))
fit1 <- with(dat,
                predict(loess(resistivity~easting*northing, span = 0.25,
                        degree = 2), sg1))
require(lattice)
levelplot(fit1 ~ sg1$easting * sg1$northing,
          col.regions=RedGrayBlue,
          cuts = 9,
          aspect=2.4, xlab = "Easting (km)", ylab = "Northing (km)",
          main="cleveland.soil - 2D smooth of Resistivity")

# }
# NOT RUN {
# 3D loess plot with data overlaid
require(rgl)
bg3d(color = "white")
clear3d()
points3d(dat$easting, dat$northing, dat$resistivity / 100,
         col = rep("gray50", nrow(dat)))
surface3d(seq(.15, 1.410, by = .015),seq(.150, 3.645, by = .015),
          fit1/100, alpha=0.9, col=rep("wheat", length(fit1)),
          front="fill", back="fill")
# }