excProb: Exceedance probabilities In geostatsp: Geostatistical Modelling with Likelihood and Bayes

 excProb R Documentation

Exceedance probabilities

Description

Calculate exceedance probabilities pr(X > threshold) from a fitted geostatistical model.

Usage

``````excProb(x, threshold=0, random=FALSE, template=NULL, templateIdCol=NULL,
nuggetInPrediction=TRUE)
``````

Arguments

 `x` Output from either the `lgm` or `glgm` functions, or a list of two-column matrices with columns named `x` and `y` containing the posterior distributions of random effects, as produced by `inla`. `threshold` the value which the exceedance probability is calculated with respect to. `random` Calculate exceedances for the random effects, rather than the predicted observations (including fixed effects). `template` A `SpatRaster` or `SpatVector` object which the results will be contained in. `templateIdCol` The data column in `template` corresponding to names of `marginals` `nuggetInPrediction` If `TRUE`, calculate exceedance probabilities of new observations by adding the nugget effect. Otherwise calculate probabilities for the latent process. Ignored if `x` is output from `glgm`.

Details

When `x` is the output from `lgm`, pr(Y>threshold) is calculated using the Gaussian distribution using the Kriging mean and conditional variance. When `x` is from the `glgm` function, the marginal posteriors are numerically integrated to obtain pr(X > threshold).

Value

Either a vector of exceedance probabilities or an object of the same class as `template`.

Examples

``````	data('swissRain')
swissRain = unwrap(swissRain)
swissAltitude = unwrap(swissAltitude)
swissBorder = unwrap(swissBorder)
swissFit =  lgm("rain", swissRain, grid=30,
boxcox=0.5,fixBoxcox=TRUE,	covariates=swissAltitude)
swissExc = excProb(swissFit, 20)
mycol = c("green","yellow","orange","red")
mybreaks = c(0, 0.2, 0.8, 0.9, 1)
plot(swissBorder)
legend("topleft",legend=mybreaks, col=c(NA,mycol))

if(requireNamespace("INLA", quietly=TRUE) ) {
# not all versions of INLA support blas.num.threads

swissRain\$sqrtrain = sqrt(swissRain\$rain)
swissFit2 =  glgm(formula="sqrtrain",data=swissRain, grid=40,
covariates=swissAltitude,family="gaussian")
swissExc = excProb(swissFit2, threshold=sqrt(30))
swissExc = excProb(swissFit2\$inla\$marginals.random\$space, 0,
template=swissFit2\$raster)

}

``````

geostatsp documentation built on Sept. 23, 2023, 1:06 a.m.