R/blankTime.R

In USGS-R/EGRET: Exploration and Graphics for RivEr Trends

#'  Deletes the computed values during periods of time when there are no sample data
#'
#'  This function is used when the data analyst believes that a gap in the sample data record
#'  is so long that estimates during that period are not reliable. 
#'  This is only used for periods of several years in duration. 
#'  For this period, the values of Conc, Flux, FNConc and FNFlux are all converted to NA. 
#'
#' @param startBlank character specifying starting date of blank period, input in quotes in yyyy-mm-dd format
#' @param endBlank character specifying the ending date of blank period, input in quotes in yyyy-mm-dd format
#' @param eList named list with at least the Daily dataframe
#' @keywords water-quality statistics
#' @return eList named list with modified Daily data frame.
#' @details
#' The startBlank and endBlank arguments should generally coincide with the starting and
#' ending date of the period of analysis that is being used.  startBlank should be
#' placed fairly close to the start of the period of no data and endBlank should
#' be placed fairly close to the end of the period of no data.  They do not eliminate
#' any water quality data from the set of data being used to estimate the model,
#' they only eliminate results computed for the specified blank period.  If the data
#' set has more than one large data gap the \code{blankTime()} function can be used
#' multiple times to blank out multiple sets of results.
#' 
#' @export
#' @examples
#' startBlank = "2004-10-01"
#' endBlank = "2006-09-30"
#' eList <- Choptank_eList
#' eList <- blankTime(eList, startBlank, endBlank)
blankTime<-function(eList, startBlank, endBlank) {
  
  localDaily <- getDaily(eList)
  
  startBlank <- as.Date(startBlank)
  endBlank <- as.Date(endBlank)
  startJulian <- as.numeric(julian(startBlank,origin=as.Date("1850-01-01")))
  endJulian <- as.numeric(julian(endBlank,origin=as.Date("1850-01-01")))
  bad <- localDaily$Julian >= startJulian & 
                localDaily$Julian <= endJulian
  localDaily$ConcDay <- ifelse(bad,NA,localDaily$ConcDay)
  localDaily$FluxDay <- ifelse(bad,NA,localDaily$FluxDay)
  localDaily$FNConc <- ifelse(bad,NA,localDaily$FNConc)
  localDaily$FNFlux <- ifelse(bad,NA,localDaily$FNFlux)
  
  wrtdsK <- all(c("GenConc", "GenFlux") %in% names(localDaily))
  if(wrtdsK){
    localDaily$GenConc <- ifelse(bad,NA,localDaily$GenConc)
    localDaily$GenFlux <- ifelse(bad,NA,localDaily$GenFlux)
  }
  
  eList$Daily <- localDaily
  
  return(eList)		
}