all_spei_viz: all_spei_viz

In seschaub/getSpei: getSpei converting SPEI netCDF files to R data frames. R package.

Description

all_spei_viz converts netCDF files of the Global SPEI database into a list, which comprises a single 'brick' of the array of the SPEI netCDF and a grid ready for visualization. The list can be used for visualizing global SPEI values for a specific year and month. Note this function is based on netCDF data, which starts in 1901 (current standard).

Usage

all_spei_viz(spei_file,year,month) 

Arguments

spei_file	spei_file is a string. The string is the SPEI netCDF filename without filename extension (i.e. .nc). The netCDF file needs to be downloaded from the Global SPEI database before using this function.
year	year indicates the year of interest.
month	month indicates the year of interest.

Note

The function returns a list, which comprises data: contains global SPEI information of one month in one year. grid: grid of the SPEI information.

The function are based on a work from Bartlein P. J. (R for Earth-System Science).

SPEI values should be compared with values available in the SPEI Global Drought Monitor

Author(s)

Sergei Schaub, ETH Zürich, Agricultural Economics and Policy Group & Grassland Sciences Group

Please cite the package as: Schaub, S. (2019) getSpei: converting SPEI netCDF files to R data frames. R package. Version 3.4.19

References

Beguería, S., Latorre, B., Reig, F. & Vicente-Serrano, S.M. (2019) The Standardised Precipitation-Evapotranspiration Index (http://spei.csic.es/index.html)

See Also

all_spei, spec_spei

Examples

# set working directory to directory where speixx.nc files are stored. 
workdir <- "H:/folder1/folder2"
setwd(workdir)

# run function
list1 <- all_spei_viz(c("spei01"), year = 2003, month = 8) 

# visualizing
grid1 <- list1$grid
d1    <- list1$data
cutoffs <- c(-2, -1.5, -1, 1, 1.5, 2)
levelplot(d1 ~ lon * lat, data = grid1, at = cutoffs, cuts = 6, pretty = T, col.regions = (rev(brewer.pal(10, "RdBu"))))

For a complete demonstration of this package, refer to getSpei website

seschaub/getSpei documentation built on May 5, 2019, 8:16 a.m.