R/convert_Time.R

In USGS-R/sedReview: A package and shiny GUI for review of discrete water-quality sediment records and box coefficient exploration of data stored in the USGS NWIS system

# Companion function to get_localNWIS to convert dates to proper time zone
convertTime <- function(datetime,timezone,daylight){
  
  datetime <- as.POSIXct(datetime, tz="GMT")
  ##Format date times to posixct with timezone, NWIS has 4 slots for characters followed by a tab, so for 3 letters you need 1 space and 1 tab after
  offsetLibrary <- setNames(c(00,
                              -03.5,
                              -04,
                              -05,
                              -06,
                              -07,
                              -08,
                              -09,
                              -10,
                              -11,
                              -12,
                              +12,
                              +12,
                              +12,
                              +11,
                              +10,
                              +10,
                              +10,
                              +10,
                              +09.5,
                              +09.5,
                              +09.5,
                              +09,
                              +09,
                              +08.5,
                              +08,
                              +08,
                              +08,
                              +07.5,
                              +07,
                              +06,
                              +05,
                              +04,
                              +03.5,
                              +03,
                              +02,
                              +02,
                              +01,
                              +01,
                              +01,
                              +01,
                              +01,
                              +01,
                              +01,
                              +01,
                              +01,
                              +01,
                              00,
                              -01,
                              -02,
                              -03,
                              -03.5,
                              +04.5), 
                            c("UTC   ",
                              "NST   ",
                              "AST   ",
                              "EST   ",
                              "CST   ",
                              "MST   ",
                              "PST   ",
                              "AKST  ",
                              "HST   ",
                              "ZP-11 ",
                              "IDLW  ",
                              "IDLE  ",
                              "NZST  ",
                              "NZT   ",
                              "ZP11  ",
                              "AEST  ",
                              "EAST  ",
                              "GST   ",
                              "LIGT  ",
                              "ACST  ",
                              "CAST  ",
                              "SAT   ",
                              "JST   ",
                              "KST   ",
                              "MT    ",
                              "AWST  ",
                              "CCT   ",
                              "WST   ",
                              "JT    ",
                              "WAST  ",
                              "ZP6   ",
                              "ZP5   ",
                              "ZP4   ",
                              "IT    ",
                              "BT    ",
                              "EET   ",
                              "IST   ",
                              "CET   ",
                              "DNT   ",
                              "DST   ",
                              "FST   ",
                              "MET   ",
                              "MEWT  ",
                              "MEZ   ",
                              "NOR   ",
                              "SET   ",
                              "SWT   ",
                              "WET   ",
                              "WAT   ",
                              "ZP-2  ",
                              "ZP-3  ",
                              "NFT   ",
                              "AFT   "))
  offset <- unname(offsetLibrary[timezone]) * 60 * 60
  daylight.offset <- ifelse (daylight == "Y", 60*60,0)
  
  date.adj <- datetime + offset + daylight.offset
  return(date.adj)
}