qtplot.gumbel {VGAM} | R Documentation

## 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"` or `"egumbel"`.
`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`.

### Details

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

### 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.

### Note

Unlike `gumbel`, one cannot have `percentiles=NULL`.

### Author(s)

Thomas W. Yee

### See Also

`gumbel`.

### Examples

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

    ## Not run:
    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)

    qtplot(fit1, perc=97, mpv=FALSE, lcol=3, tcol=3,
           lwd=2, tadj=0.4, add=TRUE) -> i
    head(i@post$qtplot$fitted)
    ## End(Not run)

[Package VGAM version 0.7-9 Index]