spatial_spi: Wrapper function from the SCI and SPEI packages to calculate...

In obaezvil/SpatIndex: Calculate spatially distributed hydroclimatological indices

Wrapper function from the SCI and SPEI packages to calculate the spatially-distributed Standardized Precipitation Index (SPI)

Description

Wrapper function from the SCI and SPEI packages to calculate the spatially-distributed Standardized Precipitation Index (SPI)

Usage

spatial_spi(
  P_data,
  scale,
  ref_start = NULL,
  ref_end = NULL,
  distribution = "Gamma",
  fit = "ub-pwm",
  na.rm = TRUE,
  package = "SCI",
  ...
)

Arguments

P_data	'SpatRaster' object that contains spatially-distributed monthly precipitation data that will be used to calculate the SPI. This 'SpatRaster' must include the time that corresponds to the dates of the respective layers. They can be set with the function time of the terra package.
scale	Integer value that represents the time scale at which the SPI will be computed.
ref_start	optional value that represents the starting point of the reference period used for computing the index. The date should be introduced as '%Y-%m'. For example: "1989-02". The default is NULL, which indicates that the first layer in the 'SpatRaster' will be used as starting point.
ref_end	Optional value that represents the ending point of the reference period used for computing the index. The date should be introduced as '%Y-%m'. For example: "1989-02". The default is NULL, which indicates that the last layer in the 'SpatRaster' will be used as ending point.
distribution	Optional value indicating the name of the distribution function to be used for computing the SPI (one of 'log-Logistic', 'Gamma' and 'PearsonIII'). Defaults to 'Gamma' for SPI.
fit	Optional value indicating the name of the method used for computing the distribution function parameters (one of 'ub-pwm', 'pp-pwm' and 'max-lik'). Defaults to 'ub-pwm'.
na.rm	Should the NA values be removed? Set to TRUE.
package	Either 'SCI' or 'SPEI'. Should the SCI or SPEI package be used in the implementation?
...	Additional variables that can be used for the 'spi' function of the SPEI package.

Value

Spatially-distributed SPI values.

obaezvil/SpatIndex documentation built on Aug. 9, 2024, 3:42 p.m.