simLgcp: Simulate a log-Gaussian Cox process

In geostatsp: Geostatistical Modelling with Likelihood and Bayes

Simulate a log-Gaussian Cox process

Description

Give covariates and model parameters, simulates a log-Gaussian Cox process

Usage

	simLgcp(param, covariates=NULL, betas=NULL, 
	offset=NULL,
	  rasterTemplate=covariates[[1]], n=1, ...)
	simPoissonPP(intensity)

Arguments

param	A vector of named model parameters with, at a minimum names range and shape (see Details), and optionally variance (defaults to 1). For Geometric Anisotropy add anisoRatio and either anisoAngleDegrees or anisoAngleRadians
covariates	Either a raster stack or list of rasters and SpatVectors (with the latter having only a single data column).
betas	Coefficients for the covariates
offset	Vector of character strings corresponding to elements of covariates which are offsets
rasterTemplate	Raster on which the latent surface is simulated, defaults to the first covariate.
n	number of realisations to simulate
...	additional arguments, see \Sexpr[results=rd]{c( '\\\code{RFsimulate} in the \\\code{RandomFields} package', '\\\command{\\\\link[RandomFields]{RFsimulate}}' )[1+requireNamespace('RandomFields', quietly=TRUE)]}.
intensity	Raster of the intensity of a Poisson point process.

Value

A list with a events element containing the event locations and a SpatRaster element containing a raster stack of the covariates, spatial random effect, and intensity.

Examples

mymodel = c(mean=-0.5, variance=1, 
				range=2, shape=2)

myraster = rast(nrows=15,ncols=20,xmin=0,xmax=10,ymin=0,ymax=7.5)

# some covariates, deliberately with a different resolution than myraster
covA = covB = myoffset = rast(ext(myraster), 10, 10)
values(covA) = as.vector(matrix(1:10, 10, 10))
values(covB) = as.vector(matrix(1:10, 10, 10, byrow=TRUE))
values(myoffset) = round(seq(-1, 1, len=ncell(myoffset)))

myCovariate = list(a=covA, b=covB, offsetFooBar = myoffset)

myLgcp=simLgcp(param=mymodel, 
	covariates=myCovariate, 
	betas=c(a=-0.1, b=0.25), 
	offset='offsetFooBar',
	rasterTemplate=myraster)

plot(myLgcp$raster[["intensity"]], main="lgcp")
points(myLgcp$events)

myIntensity = exp(-1+0.2*myCovariate[["a"]])
myPoissonPP = simPoissonPP(myIntensity)[[1]]
plot(myIntensity, main="Poisson pp")
points(myPoissonPP)

geostatsp documentation built on Dec. 24, 2024, 3 a.m.