VGAM (version 0.9-1)

qtplot.gumbel: Quantile Plot for Gumbel Regression

Description

Plots quantiles associated with a Gumbel model.

Usage

qtplot.gumbel(object, plot.it = TRUE,
    y.arg = TRUE, spline.fit = FALSE, label = TRUE,
    R = object@misc$R, percentiles = object@misc$percentiles,
    add.arg = FALSE, mpv = object@misc$mpv,
    xlab = NULL, ylab = "", main = "",
    pch = par()$pch, pcol.arg = par()$col,
    llty.arg = par()$lty, lcol.arg = par()$col, llwd.arg = par()$lwd,
    tcol.arg = par()$col, tadj = 1, ...)

Arguments

object

A VGAM extremes model of the Gumbel type, produced by modelling functions such as vglm and vgam with a family function either "gumbel"

plot.it

Logical. Plot it? If FALSE no plot will be done.

y.arg

Logical. Add the raw data on to the plot?

spline.fit

Logical. Use a spline fit through the fitted percentiles? This can be useful if there are large gaps between some values along the covariate.

label

Logical. Label the percentiles?

R

See gumbel.

percentiles

See gumbel.

add.arg

Logical. Add the plot to an existing plot?

mpv

See gumbel.

xlab

Caption for the x-axis. See par.

ylab

Caption for the y-axis. See par.

main

Title of the plot. See title.

pch

Plotting character. See par.

pcol.arg

Color of the points. See the col argument of par.

llty.arg

Line type. Line type. See the lty argument of par.

lcol.arg

Color of the lines. See the col argument of par.

llwd.arg

Line width. See the lwd argument of par.

tcol.arg

Color of the text (if label is TRUE). See the col argument of par.

tadj

Text justification. See the adj argument of par.

...

Arguments passed into the plot function when setting up the entire plot. Useful arguments here include sub and las.

Value

• The object with a list called qtplot in the post slot of object. (If plot.it = FALSE then just the list is returned.) The list contains components
• fitted.values
  The percentiles of the response, possibly including the MPV.
• percentiles
  The percentiles (small vector of values between 0 and 100.

Details

There should be a single covariate such as time. The quantiles specified by percentiles are plotted.

See Also

gumbel.

Examples

ymat <- as.matrix(venice[, paste("r", 1:10, sep = "")])
fit1 <- vgam(ymat ~ s(year, df = 3), gumbel(R = 365, mpv = TRUE),
             data = venice, trace = TRUE, na.action = na.pass)
head(fitted(fit1))

par(mfrow = c(1, 1), bty = "l", xpd = TRUE, las = 1)
qtplot(fit1, mpv = TRUE, lcol = c(1, 2, 5), tcol = c(1, 2, 5),
       lwd = 2, pcol = "blue", tadj = 0.4, ylab = "Sea level (cm)")

qtplot(fit1, perc = 97, mpv = FALSE, lcol = 3, tcol = 3,
       lwd = 2, tadj = 0.4, add = TRUE) -> saved
head(saved@post$qtplot$fitted)