R/metadata_grdc.R

In maibrittbergh/dischanalyst: Analyses Hydrological Data, especially Discharge Data

#'Metadata for GRDC Dataset
#'
#' @description Returns metadataset of GRDC-Dataset for one country. Dataset needs to be saved locally.
#'
#' @param Country character; Abbrevation used in GRDC-Dataset for specific country. e.g. "DE" for Germany.
#' @param path character; Pathway to local grdc_discharge folder on computer
#'
#' @return data.frame; metadata of GRDC-Dataset and a given Country. Metadata contains information about: The GRDC-number, the name of the river, the name of the station, the country, the catchment area, the altitude, the startmonth/startyear of the measurements, the endmonth/endyear of the measurements, the length of the timeseries, the longitude and the latitude.
#' @export
#'
#' @examples
#' \dontrun{
#' metadata_germany=metadata_grdc("DE","/Users/username/Desktop/folderone/datafolder/grdc_03_2021/grdc_disc/" )
#' }
#'#' @source \url{https://www.bafg.de/GRDC/EN/Home/homepage_node.html}
#'
metadata_grdc=function(Country, path){

  files=list.files(path)
  l=length(files)
  vec=as.logical(rep(0,l))




  for (i in 1:l){
    g=c(path,"/" ,files[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=150)
    s
    p=grep("Country", s)

    vec[i]=identical(s[p+1],  Country)
  }

  COUNTRY=which(vec==TRUE)
  file_Country=files[COUNTRY]

  # GRDC_NUMBER


  no_length=length(file_Country)
  grdc_no=rep(0, no_length)
  for (i in 1:no_length){
    grdc_no[i]= substring(file_Country[i], 1,7)
  }
  grdc_no=as.numeric(grdc_no)




  #river
  river=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=80)
    p=grep("River", s)

    river[i]=paste(s[(p+1)], s[p+2] )

  }

  river=sub("#","", river)



  for ( i in 1:no_length){ #Fehler: Leerzeichen

    nch=nchar(river[i])
    lastdigit=substr(river[i],nch,nch)
    if (lastdigit==" "){
      river[i]=substr(river[i], 1, (nch-1))
    }
  }






  #station

  station=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=80)
    p=grep("Station", s)

    station[i]=paste(s[(p+1)], s[p+2] )

  }

  station=sub("#","", station)


for ( i in 1:no_length){ #Fehler: Leerzeichen

  nch=nchar(station[i])
  lastdigit=substr(station[i],nch,nch)
if (lastdigit==" "){
  station[i]=substr(station[i], 1, (nch-1))
}
}





  #country


  country=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=80)
    p=grep("Country", s)

    country[i]=s[(p+1)]

  }

  #catchment area

  catch_area=rep(0, no_length)

  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=80)
    p=grep("area", s)

    catch_area[i]=as.numeric(s[(p+2)])

  }




  #altitude

  altitude=rep(0, no_length)

  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=80)
    p=grep("Altitude", s)

    altitude[i]=as.numeric(s[(p+3)])

  }

  # startday

  startday=rep(0, no_length)

  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=120)
    p=grep("Time", s)

    startday[i]=s[(p+2)]

  }
  startday

  #startyear

  startyear=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=120)
    p=grep("Time", s)

    startyear[i]=as.numeric(substring(s[p+2],1,4))

  }


  #endday
  endday=rep(0, no_length)

  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=120)
    p=grep("Time", s)

    endday[i]=s[(p+4)]

  }



  #endyear

  endyear=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=120)
    p=grep("Time", s)

    endyear[i]=as.numeric(substring(s[p+4],1,4))

  }





  #time_series

  d_years=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=120)
    p=grep("years", s)

    d_years[i]=as.numeric(s[p+1])

  }




  #Longitude
  longitude=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=60)
    p=grep("Longitude", s)

    longitude[i]=as.numeric(s[p+2])

  }

  longitude=as.numeric(longitude)
  #Latitude
  latitude=rep(0, no_length)
  for (i in 1:no_length){
    g=c(path,"/" ,file_Country[i])
    h=paste(g, collapse=" ")
    h=sub(" / ", "/",h)
    s=scan(h, what="character", nmax=60)
    p=grep("Latitude", s)

    latitude[i]=as.numeric(s[p+2])

  }
  latitude=as.numeric(latitude)
  #Create Data.Frame


   metadata=as.data.frame(cbind(grdc_no, river, station, country, catch_area, altitude, startday, endday, startyear,endyear, d_years, longitude, latitude))
metadata$grdc_no=as.numeric(metadata$grdc_no)
metadata$catch_area=as.numeric(metadata$catch_area)
metadata$altitude=as.numeric(metadata$altitude)
metadata$startyear=as.numeric(metadata$startyear)
metadata$endyear=as.numeric(metadata$endyear)
metadata$d_years=as.numeric(metadata$d_years)
metadata$longitude=as.numeric(metadata$longitude)
metadata$latitude=as.numeric(metadata$latitude)




n=nrow(metadata)

doubles=rep(F, n-1)
  for ( i in 1:(n-1)){

    doubles[i]=(metadata[i,]==metadata[i+1,])

  }

if(any(doubles==T)){
  true=which(doubles==T)
  metadata=metadata[-true,]
  return(metadata)
}else{return(metadata)}





}