GAM-IDF: a web tool for fitting IDF equations from daily rainfall data

This paper aims to present the genetic algorithm methodology for IDF (GAM-IDF), addressing its motivation, conception, implementation and functionalities. GAM-IDF was coded in R for web and ideated to fit IDF equations from daily rainfall data, considering: 1) importation of a daily rainfall series or an annual maximum daily rainfall series; 2) trend analysis; 3) fit of simple and multiparameter probability density functions and calculation of quantiles; 4) robust goodness-of-fit tests; 5) disaggregation of daily rainfall for different sets of constants; 6) fit of IDF equations through a genetic algorithm. This tool provides the graph containing the IDF curves and the parameters of the fitted equation. In addition, GAM-IDF provides a calculator with the IDF equation along with its fitted parameters. GAM-IDF is free, has a friendly interface, can be used in computers and smartphones, and uses state-of-the-art techniques to fit IDF equations from daily rainfall data.