EVPlotAdd: Add lines and/or points to an extreme value plot

In UKFE: UK Flood Estimation

Add lines and/or points to an extreme value plot

Description

Functionality to add extra lines or points to an extreme value plot (derived from the EVPlot function).

Usage

EVPlotAdd(
  Pars,
  dist = "GenLog",
  Name = "Adjusted",
  MED = NULL,
  xyleg = NULL,
  col = "red",
  lty = 1,
  pts = NULL,
  ptSym = NULL
)

Arguments

Pars	a numeric vector of length two. The first is the Lcv (linear coefficient of variation) and the second is the Lskew (linear skewness).
dist	distribution name with a choice of "GenLog", "GEV", "GenPareto", "Kappa3", and "Gumbel"
Name	character string. User chosen name for points or line added (for the legend)
MED	The two year return level. Necessary in the case where the EV plot is not scaled
xyleg	a numeric vector of length two. They are the x and y position of the symbol and text to be added to the legend.
col	The colour of the points of line that have been added
lty	An integer. The type of line added
pts	A numeric vector. An annual maximum sample, for example. This is for points to be added
ptSym	An integer. The symbol of the points to be added

Details

A line can be added using the Lcv and Lskew based on one of four distributions (Generalised extreme value, Generalised logistic, Gumbel, Generalised Pareto). Points can be added as a numeric vector. If a single point is required, the base points() function can be used and the x axis will need to be log(RP-1).

Value

Additional, user specified line or points to an extreme value plot derived from the EVPlot function.

Author(s)

Anthony Hammond

Examples

# Get an AMAX sample and plot the growth curve with the GEV distribution
am_203018 <- GetAM(203018)
EVPlot(am_203018$Flow, dist = "GEV")

# Now add a line (dotted and red) for the generalised logistic distribution
# First get the Lcv and Lskew using the L-moments function
pars <- as.numeric(LMoments(am_203018[, 2])[c(5, 6)])
EVPlotAdd(
  Pars = pars, dist = "GenLog", Name = "GenLog",
  xyleg = c(-5.2, 2.65), lty = 3
)

# Now add a line for the Gumbel distribution which is dark green and dashed
EVPlotAdd(
  Pars = pars[1], dist = "Gumbel", Name = "Gumbel",
  xyleg = c(-5.19, 2.5), lty = 3, col = "darkgreen"
)

# Now plot afresh and get another AMAX and add the points
EVPlot(am_203018$Flow, dist = "GEV")
am_27090 <- GetAM(27090)
EVPlotAdd(xyleg = c(-4.9, 2.65), pts = am_27090[, 2], Name = "27090")

UKFE documentation built on Nov. 5, 2025, 6:25 p.m.