| rmaxstab {SpatialExtremes} | R Documentation |
This functions generates realisation from a max-stable random field.
rmaxstab(n, coord, cov.mod = "gauss", grid = FALSE, control = list(), ...)
n |
Integer. The number of observations. |
coord |
A vector or matrix that gives the coordinates of each location. Each row corresponds to one location - if any. |
cov.mod |
A character string that gives the max-stable model. This must be one of "gauss" for the Smith model or "whitmat", "cauchy", "powexp" and "bessel" for the Schlather model with the given correlation family. |
grid |
Logical. Does the coordinates represent grid points? |
control |
A named list with arguments 'nlines' (number of lines of the TBM simulation), 'method' the name of the simulation method - must be one of 'exact' or 'tbm', and 'uBound' the uniform upper bound. See details. |
... |
The parameters of the max-stable model. See details. |
Users must supply the parameters for the max-stable model. For the
Schlather model, users should supply the "sill", "range" and "smooth"
parameter values. For the Smith model, if coord is univariate
you must specify var, otherwise users should supply the
covariance parameters i.e. parameters with names such as cov11,
cov12, ...
Here are the details for each allowed components of 'control'. If
'method' is NULL (default), the function tries to find the
most appropriate simulation technique. If 'nlines' is NULL, it
is set to 1000. If 'uBound' is NULL, it is set to reasonable
values - for example 3.5 for the Schalther model.
A matrix containing observations from the required max-stable
model. Each column represents one stations. If grid = TRUE, the
function returns an array of dimension nrow(coord) x nrow(coord) x n.
Mathieu Ribatet
Schlather, M. (2002) Models for Stationary Max-Stable Random Fields. Extremes 5:1, 33–44.
Smith, R. L. (1990) Max-stable processes and spatial extremes. Unpublished manuscript.
fitmaxstab
## 1. Smith's model set.seed(8) x <- seq(0, 10, length = 200) coord <- cbind(x, x) data <- rmaxstab(1, coord, cov11 = 9/8, cov12 = 0, cov22 = 9/8, grid = TRUE) ##We change the margins for visibility filled.contour(x, x, sqrt(data[,,1])) ## 2. Schlather's model coord <- matrix(runif(100, 0, 15), ncol = 2) data <- rmaxstab(100, coord, cov.mod = "whitmat", sill = 1, range = 10, smooth = 1)