R/usgs_daily_dl.R

In jstagge/staggefuncs: General Personal Functions for James Stagge

#' Download daily data from USGS
#'
#' Use the dataRetrieval package to download daily stream flows.
#'
#' @param site_id USGS site id
#' @param param_cv USGS parameter id
#' @param dest_folder location to save file
#'
#' @return dl_result a character stating "Success" or "Failure"
#'
#'
#' @export



usgs_daily_dl <- function(site_id, parameterCd = "00060", dest_folder = getwd()) {
	require(dataRetrieval)	
	### Create url for the data location at the USGS website using dataRetrieval package
#	url <- 	constructNWISURL(site_id, parameterCd = parameterCd, startDate = "",
#endDate = "", service="dv", format="tsv")

	### The constructNWISURL command didn't work
	url <- paste0("https://waterservices.usgs.gov/nwis/dv/?site=",site_id,"&format=rdb,1.0&ParameterCd=00060&StatCd=00003&startDT=1851-01-01")

	### Download file with a catch for failures
	dl_location <- file.path(dest_folder, paste0(site_id,"_",param_cd,"_daily.txt"))
	dl_result <- try(download.file(url, destfile = dl_location, method="curl"), silent = TRUE)
	
	### If dl_result works (equals zero) and the first character is a hash, return result.  If not, delete mistake download
	if (dl_result == 0 & readChar(dl_location, 1)=="#") {
			dl_result <- "Success"
		} else {
			### Delete file	and return failure
			file.remove(dl_location)
			dl_result <- "Failure"
		}
	return(dl_result)
	}