agridat (version 1.23)

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.

Electronic version of the data was retrieved from http://lib.stat.cmu.edu/datasets/Andrews/

Cleaned version from Luke Tierney https://homepage.stat.uiowa.edu/~luke/classes/248/examples/soil

Examples

if (FALSE) {

  library(agridat)
  data(cleveland.soil)
  dat <- cleveland.soil

  # Similar to Cleveland fig 4.64
  ## libs(latticeExtra)
  ## redblue <- colorRampPalette(c("firebrick", "lightgray", "#375997"))
  ## levelplot(resistivity ~ easting + northing, data = dat,
  ##           col.regions=redblue,
  ##           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 = .02),
                     northing = seq(.150, 3.645, by = .02))
  lo1 <- loess(resistivity~easting*northing, data=dat, span = 0.1, degree = 2)
  fit1 <- predict(lo1, sg1)
  libs(lattice)
  redblue <- colorRampPalette(c("firebrick", "lightgray", "#375997"))
  levelplot(fit1 ~ sg1$easting * sg1$northing,
            col.regions=redblue,
            cuts = 9,
            aspect=2.4, xlab = "Easting (km)", ylab = "Northing (km)",
            main="cleveland.soil - 2D smooth of Resistivity")
  
  # 3D loess plot with data overlaid
  libs(rgl)
  bg3d(color = "white")
  clear3d()
  points3d(dat$easting, dat$northing, dat$resistivity / 100,
           col = rep("gray50", nrow(dat)))
  rgl::surface3d(seq(.15, 1.410, by = .02),
                 seq(.150, 3.645, by = .02),
                 fit1/100, alpha=0.9, col=rep("wheat", length(fit1)),
                 front="fill", back="fill")
  close3d()
}