readDWD: Process data from the DWD CDC FTP Server

Description

Read climate data that was downloaded with dataDWD(). The data is unzipped and subsequently, the file(s) are read, processed and returned as a data.frame / terra raster object.

For observational data, new users are advised to set varnames=TRUE to obtain more informative column names.

readDWD will call internal (but documented) subfunctions depending on the argument type, see the overview in fileType().

Not all arguments to readDWD are used for all subfunctions, e.g. fread is used only by readDWD.data, while dividebyten is used in readDWD.raster and readDWD.asc.

file can be a vector with several filenames. Most other arguments can also be a vector and will be recycled to the length of file.

Usage

readDWD(
  file,
  type = fileType(file),
  varnames = FALSE,
  fread = NA,
  format = NA,
  tz = "GMT",
  hr = 0,
  dividebyten = TRUE,
  var = "",
  progbar = !quiet,
  quiet = rdwdquiet(),
  quietread = quiet,
  ...
)

Value

For observational data, an invisible data.frame of the desired dataset, or a named list of data.frames if length(file) > 1.

For gridded data, terra raster objects.

Arguments

file: Char (vector): name(s) of the file(s) downloaded with dataDWD(), e.g. "~/DWDdata/tageswerte_KL_02575_akt.zip" or "~/DWDdata/RR_Stundenwerte_Beschreibung_Stationen.txt"
type: Character (vector) determining which subfunction to call. DEFAULT: fileType(file).
varnames: Logical (vector): Expand column names? Only used in readDWD.data(). DEFAULT: FALSE (for backward compatibility)
fread: Logical (vector): read fast? Used in readDWD.data(). DEFAULT: NA
format, tz: Format and time zone of time stamps, see readDWD.data()
hr: Integer code to merge historical and recent file. Used here, but documented in detail in readDWD.data(). DEFAULT: 0 (ignore argument)
dividebyten: Logical (vector): Divide the values in raster files by ten? That way, [1/10 mm] gets transformed to [mm] units. Used in readDWD.radar(), readDWD.raster() and readDWD.asc(). DEFAULT: TRUE
var: var for readDWD.nc(). DEFAULT: ""
progbar: Logical: present a progress bar with estimated remaining time? If missing and length(file)==1, progbar is internally set to FALSE, unless binary files are to be read. DEFAULT: !quiet
quiet: Logical: suppress messages? DEFAULT: FALSE through rdwdquiet()
quietread: Logical: suppress message like "Reading 1 file with readDWD.data() and fread=TRUE ...". DEFAULT: quiet
...: Further arguments passed to the internal readDWD.* subfunctions (see fileType) and from those to the underlying actual reading functions

Author

Berry Boessenkool, berry-b@gmx.de, Jul-Oct 2016, Winter 2018/19

Examples

Run this code

# see dataDWD and readDWD.* subfunctions