GeoCorrFct {GeoModels} | R Documentation |
Spatial and Spatio-temporal correlation or covariance of (non) Gaussian random fields
Description
The function computes the correlations of a spatial (or spatio-temporal or bivariate spatial) Gaussian or non Gaussian randomm field for a given correlation model and a set of spatial (temporal) distances.
Usage
GeoCorrFct(x,t=NULL,corrmodel, model="Gaussian",
distance="Eucl", param, radius=6371,n=1,
covariance=FALSE,variogram=FALSE)
Arguments
x |
A set of spatial distances. |
t |
A set of (optional) temporal distances. |
corrmodel |
String; the name of a correlation model, for the description see the Section Details. |
model |
String; the type of RF. See |
distance |
String; the name of the spatial distance. The default
is |
param |
A list of parameter values required for the covariance model. |
radius |
Numeric; a value indicating the radius of the sphere when using covariance models valid using the great circle distance. Default value is the radius of the earth in Km (i.e. 6371) |
n |
Numeric; the number of trials in a (negative) binomial random fields.
Default is |
covariance |
Logic; if TRUE then the covariance is returned. Default is FALSE |
variogram |
Logic; if FALSE then the covariance/correlation is returned. Otherwise the associated semivariogram is returned |
Value
Returns correlations or covariances values associated to a given parametric spatial and temporal correlation models.
Author(s)
Moreno Bevilacqua, moreno.bevilacqua89@gmail.com,https://sites.google.com/view/moreno-bevilacqua/home, Víctor Morales Oñate, victor.morales@uv.cl, https://sites.google.com/site/moralesonatevictor/, Christian", Caamaño-Carrillo, chcaaman@ubiobio.cl,https://www.researchgate.net/profile/Christian-Caamano
Examples
library(GeoModels)
################################################################
###
### Example 1. Covariance of a Gaussian random field with underlying
### Matern correlation model with nugget
###
###############################################################
# Define the spatial distances
#x = seq(0,1,0.002)
# Correlation Parameters for Matern model
#CorrParam("Matern")
#NuisParam("Gaussian")
# Matern Parameters
#param=list(sill=2,smooth=0.5,scale=0.2/3,nugget=0.2,mean=0)
#cc= GeoCorrFct(x=x, corrmodel="Matern", covariance=TRUE,
# param=param,model="Gaussian")
#plot(cc,ylab="Corr",lwd=2,main="Matern correlation",type="l")
################################################################
###
### Example 2. Covariance of a Gaussian random field with underlying
### Generalized Wendland-Matern correlation model
###
###############################################################
#CorrParam("GenWend_Matern")
#NuisParam("Gaussian")
# GenWend Matern Parameters
#param=list(sill=2,smooth=1,scale=0.1,nugget=0,power2=1/4,mean=0)
#cc= GeoCorrFct(x=x, corrmodel="GenWend_Matern", param=param,model="Gaussian",covariance=FALSE)
#plot(cc,ylab="Cov",lwd=2,,main="GenWend covariance",type="l")
################################################################
###
### Example 3. Semivariogram of a Tukeyh random field with underlying
### Generalized Wendland correlation model
###
###############################################################
#CorrParam("GenWend")
#NuisParam("Tukeyh")
#x = seq(0,1,0.005)
#param=list(sill=1,smooth=1,scale=0.5,nugget=0,power2=5,tail=0.1,mean=0)
#cc= GeoCorrFct(x=x, corrmodel="GenWend", param=param,model="Tukeyh",variogram=TRUE)
#plot(cc,ylab="Corr",lwd=2,main="Tukey semivariogram",type="l")
################################################################
###
### Example 4. Semi-Variogram of a LoggGaussian random field with underlying
### Kummer correlation model
###
###############################################################
#CorrParam("Kummer")
#NuisParam("LogGaussian")
# GenWend Matern Parameters
#param=list(smooth=1,sill=0.5,scale=0.1,nugget=0,power2=1,mean=0)
#cc= GeoCorrFct(x=x, corrmodel="Kummer", param=param,model="LogGaussian",
# ,covariance=TRUE,variogram=TRUE)
#plot(cc,ylab="Semivario",lwd=2,
# main="LogGaussian semivariogram",type="l")
################################################################
###
### Example 5. Covariance of Poisson random field with underlying
### Matern correlation model
###
###############################################################
#CorrParam("Matern")
#NuisParam("Poisson")
#x = seq(0,1,0.005)
#param=list(scale=0.6/3,nugget=0,smooth=0.5,mean=2)
#cc= GeoCorrFct(x=x, corrmodel="Matern", param=param,model="Poisson",covariance=TRUE)
#plot(cc,ylab="Cov",lwd=2,
# main="Poisson covariance",type="l")
################################################################
###
### Example 6. Space time semivariogram of a Gaussian random field
### with separable Matern correlation model
###
###############################################################
## spatial and temporal distances
#h<-seq(0,3,by=0.04)
#times<-seq(0,3,by=0.04)
# Correlation Parameters for the space time separable Matern model
#CorrParam("Matern")
#NuisParam("Gaussian")
# Matern Parameters
#param=list(sill=1,scale_s=0.6/3,scale_t=0.5,nugget=0,mean=0,smooth_s=1.5,smooth_t=0.5)
#cc= GeoCorrFct(x=h,t=times,corrmodel="Matern_Matern", param=param,
# model="Gaussian",variogram=TRUE)
#plot(cc,lwd=2,type="l")
################################################################
###
### Example 7. Correlation of a bivariate Gaussian random field
### with underlying separable bivariate Matern correlation model
###
###############################################################
# Define the spatial distances
#x = seq(0,1,0.005)
# Correlation Parameters for the bivariate sep Matern model
#CorrParam("Bi_Matern")
# Matern Parameters
#param=list(sill_1=1,sill_2=1,smooth_1=0.5,smooth_2=1,smooth_12=0.75,
# scale_1=0.2/3, scale_2=0.2/3, scale_12=0.2/3,
# mean_1=0,mean_2=0,nugget_1=0,nugget_2=0,pcol=-0.2)
#cc= GeoCorrFct(x=x, corrmodel="Bi_Matern", param=param,model="Gaussian")
#plot(cc,ylab="corr",lwd=2,type="l")