rdwd (version 0.7.0)

dataDWD: Download data from the DWD CDC FTP Server

Description

Get climate data from the German Weather Service (DWD) FTP-server. The desired .zip (or .txt) dataset is downloaded into dir. If read=TRUE, it is also read, processed and returned as a data.frame.

Usage

dataDWD(file, dir = "DWDdata", force = FALSE, sleep = 0, quiet = FALSE,
  progbar = !quiet, browse = FALSE, read = TRUE, meta = substr(file,
  nchar(file) - 3, 10000) == ".txt", format = NA, ntrunc = 2, ...)

Arguments

file

Char (vector): complete file URL(s) (including base and filename.zip) as returned by selectDWD. Can be a vector with several filenames.

dir

Char: Writeable directory name where to save the downloaded file. Created if not existent. DEFAULT: "DWDdata" at current getwd()

force

Logical: always download, even if the file already exists in dir? If FALSE, it is still read (or name returned). DEFAULT: FALSE

sleep

Number. If not 0, a random number of seconds between 0 and sleep is passed to Sys.sleep after each download to avoid getting kicked off the FTP-Server. DEFAULT: 0

quiet

Logical: suppress message about directory / filenames? DEFAULT: FALSE

progbar

Logical: present a progress bar with estimated remaining time? If missing and length(file)==1, progbar is internally set to FALSE. Only works if the R package pbapply is available. DEFAULT: TRUE (!quiet)

browse

Logical: open repository via browseURL and return URL folder path? If TRUE, no data is downloaded. If file has several values, only unique folders will be opened. DEFAULT: FALSE

read

Logical: read the file(s) with readDWD? If FALSE, only download is performed and the filename(s) returned. DEFAULT: TRUE

meta

Logical (vector): is the file a meta file? Passed to readDWD. DEFAULT: TRUE for each file ending in ".txt"

format

Char (vector): format used in strptime to convert date/time column, see readDWD. DEFAULT: NA

ntrunc

Single integer: number of filenames printed in messages before they get truncated with message "(and xx more)". DEFAULT: 2

…

Further arguments passed to download.file

Value

Presuming downloading and processing were successfull: if read=TRUE, a data.frame of the desired dataset (as returned by readDWD), otherwise the filename as saved on disc (may have "_n" appended in name, see fileDWD). If length(file)>1, the output is a list of data.frames / vector of filenames. The output is always invisible.

See Also

selectDWD. readDWD, download.file. Helpful for plotting: berryFunctions::monthAxis, see also berryFunctions::climateGraph

Examples

 ## requires internet connection
# find files for a given station name and file path:
link <- selectDWD("Kupferzell-Rechbach", res="hourly", var="precipitation", per="recent")
# actually download and read files
prec <- dataDWD(link, dir="DWDdata") # the default dir
fname <- dataDWD(link, read=FALSE) # filename, no second download (unless force=TRUE)

# current and historical files:
link <- selectDWD("Potsdam", res="daily", var="kl", per="hr", outvec=TRUE); link
potsdam <- dataDWD(link)
potsdam <- do.call(rbind, potsdam) # this will partly overlap in time
plot(LUFTTEMPERATUR~MESS_DATUM, data=tail(potsdam,1000), type="l")
# Straight line marks the jump back in time
# check for equality:
dup <- which(duplicated(potsdam$MESS_DATUM))
dup_df <- which(duplicated(potsdam))
err <- dup[ ! dup %in% dup_df]
err <- potsdam[potsdam$MESS_DATUM %in% potsdam$MESS_DATUM[err], ]
err <- err[order(err$MESS_DATUM),]
View(err) # WINDGESCHWINDIGKEIT (wind speed) has been slightly changed
# Keep only historical dataset:
potsdam <- potsdam[!duplicated(potsdam$MESS_DATUM),]

# several files:
link <- c(link, selectDWD("Potsdam", res="daily", var="kl", per="hr", outvec=TRUE))
clim <- dataDWD(link)
fname <- dataDWD(link, read=FALSE)
clim <- readDWD(fname)
unzip(zipfile=paste0("DWDdata/",fname[1]), exdir="DWDdata/Testunzip")
# There's quite some important meta information there!

plot(prec$MESS_DATUM, prec$NIEDERSCHLAGSHOEHE, main="DWD hourly rain Kupferzell", col="blue",
     xaxt="n", las=1, type="l", xlab="Date", ylab="Hourly rainfall  [mm]")
monthAxis(1, ym=T)

d <- dataDWD(selectDWD(id="05692", res="daily", var="kl", per="recent"))
# writes into the same folder (dir="DWDdata")

folder <- dataDWD(link, browse=T)
folder

# With many files, use sleep
links <- selectDWD(res="daily", var="solar", meta=FALSE)
sol <- dataDWD(links, sleep=20) # random waiting time after download (0 to 20 secs)

# Real life example with data completeness check etc:
browseURL("http://github.com/brry/prectemp/blob/master/Code_example.R")