fitDISTRI: Fit distribution functions by L-moments, probability weighted...

In dazamora/IDFtool: Estimation Intensity-Duration-Frequency Curves for Rainfall Series

Fit distribution functions by L-moments, probability weighted moments, maximum likelihood and moments

Description

This function allows to fit several distribution functions to observed data by means of the methods L-moments, probability weighted moments, maximum likelihood and moments. It also assesses the goodness of fit test with different statistics (see goodFIT).

Usage

fitDISTRI(Intensity, Type = "Gumbel", Plot = 2, M.fit = "MLE",
  Periods, Dura, Station, CI = FALSE, iter, goodtest = FALSE,
  Resolution = 300, SAVE = FALSE)

Arguments

Intensity	a numeric vector with intensity [mm/h] values of different years for a specific time duration (e.g. 5, 15, 120 minutes, etc.).
Type	a character specifying the name of the distribution function that will be employed: exponencial, gamma, gev, gumbel, log.normal3, normal, pearson, log.pearson3 and wakeby (see selecDIST).
Plot	a number (1) to determine if it will be plotted density curves both empirical as modeled (pdf). a number (2) to determine if it will be plotted curves between return Periods and intensity computed by pdf fitted. Or use both numbers to get these graphs. If any other number is used, graphs will not appear.
M.fit	a character specifying the name of fit method employed on pdf, just three options are available: L-moments (Lmoments), Probability-Weighted Moments (PWD), Maximum Likelihood (MLE) (see MLEZ) and Moments (MME) (see MME_DIST).
Periods	a numeric vector with return periods.
Dura	a character specifying a time duration of the Intensity, (e.g. 30 min). This parameter is used to save results.
Station	a character specifying a name or number of pluviographic station where data were measured. It is used to save results.
CI	a logical value specifying whether confidence interval should be cumputed to pdf fitted by means bootstrapCI function.
iter	an integer representing number of resamples to conduct when confidence interval will be computed (see bootstrapCI). Use it only if CI is equal to TRUE.
goodtest	a logical value specifying whether goodness-fit tests should be cumputed to pdf fitted by means of goodFIT function.
Resolution	a number to determine resolution that the plot function will used to save graphs. It has two options: 300 and 600 ppi. See resoPLOT.
SAVE	a logical value. TRUE will save Plot, FALSE will just show it.

Value

A list with the fitted distribution and the parameters:

• Parameters a list with type of distribution fitted and values of its parameters

• Int.pdf a numeric vector of intensities values per each return Periods compute by pdf fitted.

• Conf.Inter a matrix with lower and upper limits of confidence interval for pdf fitted and computed for each return Periods.

• goodness.fit a data frame with statistics values of goodness of fit tests and its respective p-value, moreover information criteria are evaluated (see goodFIT)

• Info.PDF a vector with details about fit method and distribution function employed.

Author(s)

David Zamora <[e-mail]> Water Resources Engineering Research Group - GIREH

Examples

# Meteorology station in the Farfan Airport in Tulua, Colombia.
data(inten)
fit.pdf <- fitDISTRI(Intensity =inten[15:35,2], Type ="Gumbel", Plot = 12, M.fit = "LMOMENTS",
                     Periods =c(2,3,5,10,25,50,100), Dura ="5 min", Station ="2610", CI = TRUE,
                     iter =100, goodtest = TRUE,Resolution = 300, SAVE = FALSE)

dazamora/IDFtool documentation built on Jan. 1, 2023, 3:29 p.m.