freq.curve.all: Compute Frequency Curve for Almost All Distributions

In wasquith/lmomco: L-Moments, Censored L-Moments, Trimmed L-Moments, L-Comoments, and Many Distributions

Compute Frequency Curve for Almost All Distributions

Description

This function is dispatcher on top of a select suite of quaCCC functions that compute frequency curves for the L-moments. The term “frequency curves” is common in hydrology and is a renaming of the more widenly known by statisticians term the “quantile function.” The notation CCC represents the character notation for the distribution: exp, gam, gev, gld, glo, gno, gpa, gum, kap, nor, pe3, wak, and wei. The nonexceedance probabilities to construct the curves are derived from nonexceeds.

Usage

freq.curve.all(lmom, aslog10=FALSE, asprob=TRUE,
                     no2para=FALSE, no3para=FALSE,
                     no4para=FALSE, no5para=FALSE,
                     step=FALSE, show=FALSE,
                     xmin=NULL, xmax=NULL, xlim=NULL,
                     ymin=NULL, ymax=NULL, ylim=NULL,
                     aep4=FALSE, exp=TRUE, gam=TRUE, gev=TRUE, gld=FALSE,
                     glo=TRUE, gno=TRUE, gpa=TRUE, gum=TRUE, kap=TRUE,
                     nor=TRUE, pe3=TRUE, wak=TRUE, wei=TRUE,...)

Arguments

lmom	A L-moment object from lmoms, lmom.ub, or vec2lmom.
aslog10	Compute log10 of quantiles—note that NaNs produced in: log(x, base) will be produced for less than zero values.
asprob	The R qnorm function is used to convert nonexceedance probabilities, which are produced by nonexceeds, to standard normal variates. The Normal distribution will plot as straight line when this argument is TRUE
no2para	If TRUE, do not run the 2-parameter distributions: exp, gam, gum, and nor.
no3para	If TRUE, do not run the 3-parameter distributions: gev, glo, gno, gpa, pe3, and wei.
no4para	If TRUE, do not run the 4-parameter distributions: kap, gld, aep4.
no5para	If TRUE, do not run the 5-parameter distributions: wak.
step	Shows incremental processing of each distribution.
show	Plots all the frequency curves in a simple (crowded) plot.
xmin	Minimum x-axis value to use instead of the automatic value determined from the nonexceedance probabilities. This argument is only used is show=TRUE.
xmax	Maximum x-axis value to use instead of the automatic value determined from the nonexceedance probabilities. This argument is only used is show=TRUE.
xlim	Both limits of the x-axis. This argument is only used is show=TRUE.
ymin	Minimum y-axis value to use instead of the automatic value determined from the nonexceedance probabilities. This argument is only used is show=TRUE.
ymax	Maximum y-axis value to use instead of the automatic value determined from the nonexceedance probabilities. This argument is only used is show=TRUE.
ylim	Both limits of the y-axis. This argument is only used is show=TRUE.
aep4	A logical switch on computation of corresponding distribution—default is FALSE.
exp	A logical switch on computation of corresponding distribution—default is TRUE.
gam	A logical switch on computation of corresponding distribution—default is TRUE.
gev	A logical switch on computation of corresponding distribution—default is TRUE.
gld	A logical switch on computation of corresponding distribution—default is FALSE.
glo	A logical switch on computation of corresponding distribution—default is TRUE.
gno	A logical switch on computation of corresponding distribution—default is TRUE.
gpa	A logical switch on computation of corresponding distribution—default is TRUE.
gum	A logical switch on computation of corresponding distribution—default is TRUE.
kap	A logical switch on computation of corresponding distribution—default is TRUE.
nor	A logical switch on computation of corresponding distribution—default is TRUE.
pe3	A logical switch on computation of corresponding distribution—default is TRUE.
wak	A logical switch on computation of corresponding distribution—default is TRUE.
wei	A logical switch on computation of corresponding distribution—default is TRUE.
...	Additional parameters are passed to the parameter estimation routines such as parexp.

Value

An extensive R data.frame of frequency curves. The nonexceedance probability values, which are provided by nonexceeds, are the first item in the data.frame under the heading of nonexceeds. If a particular distribution could not be fit to the L-moments of the data; this particular function returns zeros.

Note

The distributions selected for this function represent a substantial fraction of, but not all, distributions supported by lmomco. The all and “all” in the function name and the title of this documentation is a little misleading. The selection process was made near the beginning of lmomco availability and distributions available in the earliest versions. Further the selected distributions are frequently encountered in hydrology and because these are also those considered in length by Hosking and Wallis (1997) and the lmom package.

Author(s)

W.H. Asquith

References

Hosking, J.R.M., and Wallis, J.R., 1997, Regional frequency analysis—An approach based on L-moments: Cambridge University Press.

See Also

quaaep4, quaexp, quagam, quagev, quagld, quaglo, quagno, quagpa, quagum, quakap, quanor, quape3, quawak, and quawei.

Examples

L <- vec2lmom(c(35612,23593,0.48,0.21,0.11))
Qtable1 <- freq.curve.all(L, step=TRUE, no2para=TRUE, no4para=TRUE)
## Not run: 
Qtable2 <- freq.curve.all(L, gld=TRUE, show=TRUE)
## End(Not run)

wasquith/lmomco documentation built on April 20, 2024, 7:20 p.m.