Calculation of standardized precipitation index from alpha and beta parameter of the Gamma function.

Description

calculate the standardized precipitation index, from alpha and beta parameter of the Gamma function.

Usage

SPIFromParameters(Pmon, scale =3, Param_Alpha, Param_Beta)

Arguments

Details

Analysis stations are in the columns of dataframe. the apha and beta parameters, are monthly and are in the rows of dataframe.

Input data

similar to Pm_Pisco.

Value

return values of standardized precipitation index in .txt formats.

Author(s)

Iv<c3><83><c2><a1>n Arturo Ayala Bizarro <ivan.ayala@unh.edu.pe>

Jessica Z<c3><83><c2><ba><c3><83><c2><b1>iga Mendoza <zumeje@gmail.com>

References

McKee, Thomas B. and Doesken, Nolan J. and Kleist, John. 1993. The relationship of Drought Frecuency and Duration to Time Scales. Eighth Conference on Applied Climatology

A. Belauneh and J. Adamowski. Standard Precipitation Index Drought Forecasting Using Neural Networks, Wavelet Neural Networks, and Support Vector Regression. Applied Computational Intelligence and Soft Computing, http://dx.doi.org/10.1155/2012/794061

Examples

#### Load data
data(Pm_Pisco)
data(alphaGA_SPI3)
data(betaGA_SPI3)

#### Computing SPI with Genetic Algorithms
Pmon<-Pm_Pisco
Param_Alpha <- alphaGA_SPI3
Param_Beta <- betaGA_SPI3
SPIFromParameters(Pmon, scale =3, Param_Alpha, Param_Beta)

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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Type 'demo()' for some demos, 'help()' for on-line help, or
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> library(SPIGA)
Loading required package: GA
Loading required package: foreach
Loading required package: iterators
Package 'GA' version 3.0.2
Type 'citation("GA")' for citing this R package in publications.
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/SPIGA/SPIFromParameters.Rd_%03d_medium.png", width=480, height=480)
> ### Name: Drought Index from Parameters
> ### Title: Calculation of standardized precipitation index from alpha and
> ###   beta parameter of the Gamma function.
> ### Aliases: SPIFromParameters
> 
> ### ** Examples
> 
> #### Load data
> data(Pm_Pisco)
> data(alphaGA_SPI3)
> data(betaGA_SPI3)
> 
> #### Computing SPI with Genetic Algorithms
> Pmon<-Pm_Pisco
> Param_Alpha <- alphaGA_SPI3
> Param_Beta <- betaGA_SPI3
> SPIFromParameters(Pmon, scale =3, Param_Alpha, Param_Beta)
********** Calculation Station Pm_St1 
********** Calculation Station Pm_St2 
********** Calculation Station Pm_St3 
********** Calculation Station Pm_St4 

SPIFromParameters: Successful Analysis
See the results:  /home/ddbj/DataUpdator-rgm3/target 
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>