Soil data of North Bavaria, Germany
Soil physical and chemical data collected on a field in the Weissenstaedter Becken, Germany
data(soil)
This data frame contains the following columns:
x coordinates given in cm
y coordinates given in cm
number of the samples, which were taken in this order
moisture content [Kg/Kg * 100%]
nitrate nitrogen [mg/Kg]
total nitrogen [mg/Kg]
ammonium nitrogen [mg/Kg]
dissolved organic carbon [mg/Kg]
nitrous oxide [mg/Kg dried substance]
For technical reasons some of the data were obtained as differences of two measurements (which are not available anymore). Therefore, some of the data have negative values.
Martin Schlather, schlather@math.uni-mannheim.de, https://www.wim.uni-mannheim.de/schlather/
The data were collected by Wolfgang Falk, Soil Physics Group, University of Bayreuth, Germany.
Falk, W. (2000) Kleinskalige raeumliche Variabilitaet von Lachgas und bodenchemischen Parameters [Small Scale Spatial Variability of Nitrous Oxide and Pedo-Chemical Parameters], Master thesis, University of Bayreuth, Germany.
RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
## RFoptions(seed=NA) to make them all random again
################################################################
## ##
## a geostatistical analysis that demonstrates ##
## features of the package 'RandomFields' ##
## ##
################################################################
data(soil)
str(soil)
soil <- RFspatialPointsDataFrame(
coords = soil[ , c("x.coord", "y.coord")],
data = soil[ , c("moisture", "NO3.N", "Total.N", "NH4.N", "DOC", "N20N")],
RFparams=list(vdim=6, n=1)
)
dta <- soil["moisture"]
## plot the data first
colour <- rainbow(100)
plot(dta, col=colour)
## fit by eye
gui.model <- RFgui(dta)
## fit by ML
model <- ~1 + RMwhittle(scale=NA, var=NA, nu=NA) + RMnugget(var=NA)
(fit <- RFfit(model, data=dta))
plot(fit, method=c("ml", "plain", "sqrt.nr", "sd.inv"),
model = gui.model, col=1:8)
## Kriging ...
x <- seq(min(dta@coords[, 1]), max(dta@coords[, 1]), l=121)
k <- RFinterpolate(fit, x=x, y=x, data=dta)
plot(x=k, col=colour)
plot(x=k, y=dta, col=colour)
## what is the probability that at no point of the
## grid given by x and y the moisture is greater than 24 percent?
cs <- RFsimulate(model=fit@ml, x=x, y=x, data=dta, n=50)
plot(cs, col=colour)
plot(cs, y=dta, col=colour)
Print(mean(apply(as.array(cs) <= 24, 3, all))) ## about 40 percent ...Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.