R/calc_sun_rise_set.R

In USGS-R/streamMetabolizer: Models for Estimating Aquatic Photosynthesis and Respiration

#' Calculates the time of sunrise and sunset
#' 
#' Calculates the time of sunrise and sunset based on latitude and date.
#' 
#' @param date Vector of dates in \code{Date} format.
#' @param latitude Single latitude value of site. South should be negative, 
#'   North positive
#' @return data.frame of sunrise and sunset (apparent solar time, nominally UTC)
#' @importFrom LakeMetabolizer sun.rise.set
#' @importFrom lubridate force_tz
#' @keywords internal
#' @examples
#' calc_sun_rise_set(latitude=40.75, 
#'   date=as.POSIXlt(c('2013-03-31', '2017-07-01')))
#' @seealso \link{calc_is_daytime}
#' @export
calc_sun_rise_set <- function(date, latitude) {
  
  .Deprecated
  warning("submit a GitHub issue if you want calc_sun_rise_set() to stick around")
  
  app.solar.time <- as.POSIXct(strftime(date, "%Y-%m-%d 0"), format="%Y-%m-%d %H") # use local tz, as LakeMetabolizer does
  sun.rise.set <- LakeMetabolizer::sun.rise.set(app.solar.time, latitude)
  # reformat
  data.frame(sunrise=lubridate::force_tz(sun.rise.set[,1], tz="UTC"), 
             sunset=lubridate::force_tz(sun.rise.set[,2], tz="UTC"))
}