# qqextcoeff: QQ-plot for the extremal coefficient In SpatialExtremes: Modelling Spatial Extremes

 qqextcoeff R Documentation

## QQ-plot for the extremal coefficient

### Description

This function compares the extremal coefficients estimated from a fitted max-stable process to the ones estimated semi-parametrically.

### Usage

```qqextcoeff(fitted, estim = "ST", marge = "emp", xlab = "Semi-Empirical",
ylab = "Model", ...)
```

### Arguments

 `fitted` An object of class `maxstab`. Most often, this will be the output of `fitmaxstab`, `fitcovmat` or `fitcovariance`. `estim,marge` The `estim` and `marge` options to be passed to the `fitextcoeff` function. `xlab,ylab` The x and y-axis labels. `...` Optional arguments to be passed to the `plot` function.

A QQ-plot.

Mathieu Ribatet

### References

Schlather, M. (2002) Models for Stationary Max-Stable Random Fields. Extremes 5:1, 33–44.

Schlather, M. and Tawn, J. A. (2003) A dependence measure for multivariate and spatial extreme values: Properties and inference. Biometrika 90(1):139–156.

Smith, R. L. (1990) Max-stable processes and spatial extremes. Unpublished manuscript.

`fitmaxstab`, `fitextcoeff`

### Examples

```##Define the coordinate of each location
n.site <- 30
locations <- matrix(runif(2*n.site, 0, 10), ncol = 2)
colnames(locations) <- c("lon", "lat")

##Simulate a max-stable process - with unit Frechet margins
data <- rmaxstab(50, locations, cov.mod = "gauss", cov11 = 10, cov12 =
5, cov22 = 22)

fitted <- fitmaxstab(data, locations, "gauss")
qqextcoeff(fitted)
```

SpatialExtremes documentation built on April 19, 2022, 5:06 p.m.