inst/doc/ads_vignette.R

In ecmwfr: Interface to 'ECMWF' and 'CDS' Data Web Services

## ----setup, include = FALSE---------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

# load the library
library(ncdf4)
library(terra)
library(maps)

# grab demo nc files
ncfile <- list.files(system.file(package="ecmwfr"),"*.nc", recursive = TRUE, full.names = TRUE)
ncfile <- ncfile[grepl("ads.nc", ncfile)]

## ----demo request, echo = TRUE------------------------------------------------
# Specify the data set
request <- list(
  date = "2003-01-01/2003-01-01",
  format = "netcdf",
  variable = "particulate_matter_2.5um",
  time = "00:00",
  dataset_short_name = "cams-global-reanalysis-eac4",
  target = "particulate_matter.nc"
)

## ----spatial-request, echo = TRUE, eval = FALSE-------------------------------
#  # Start downloading the data, the path of the file
#  # will be returned as a variable (ncfile)
#  file <- wf_request(
#    user     = "2345",   # user ID (for authentification)
#    request  = request,  # the request
#    transfer = TRUE,     # download the file
#    path     = "."       # store data in current working directory
#    )

## ----spatial-plot, echo = TRUE, figure = TRUE, fig.width = 8, fig.height = 6----
# Open NetCDF file and plot the data
# (trap read error on mac - if gdal netcdf support is missing)
r <- try(terra::rast(ncfile))

if(!inherits(r, "try-error")) {
  terra::plot(log(rotate(r)),
              main = "CAMS reanalysis data (particulate matter 2.5u)",
              col = rev(heat.colors(100)))
  maps::map("world", add = TRUE)
}