qtplot.gumbel {VGAM} | R Documentation

## Quantile Plot for Gumbel Regression

### Description

Plots quantiles associated with a Gumbel model.

### Usage

    qtplot.gumbel(object, show.plot = 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`, and with a family function that is either `gumbel` or `gumbelff`.
`show.plot` | 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 `show.plot = 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

    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))

    ## 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, 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)

    ## End(Not run)

[Package VGAM version 1.0-4 Index]