R/monitor_dygraph.R

In PWFSLSmoke: Utilities for Working with Air Quality Monitoring Data

#' @keywords ws_monitor
#' @export
#' @title Create Interactive Time Series Plot
#' @param ws_monitor \emph{ws_monitor} object
#' @param title title text
#' @param ylab title for the y axis
#' @param tlim optional vector with start and end times (integer or character
#'   representing YYYYMMDD[HH])
#' @param rollPeriod rolling mean to be applied to the data
#' @param showLegend logical to toggle display of the legend
#' @description This function creates interactive graphs that will be displayed
#'   in RStudio's 'Viewer' tab.
#' @return Initiates the interactive dygraph plot in RStudio's 'Viewer' tab.
#' @examples
#' \donttest{
#' # Fail gracefully if any resources are not available
#' try({
#'
#' library(PWFSLSmoke)
#'
#' # Napa Fires -- October, 2017
#' ca <- airnow_load(2017) %>%
#'   monitor_subset(tlim=c(20171001,20171101), stateCodes='CA')
#'
#' Vallejo <- monitor_subset(ca, monitorIDs='060950004_01')
#'
#' Napa_Fires <- monitor_subsetByDistance(
#'   ca,
#'   longitude = Vallejo$meta$longitude,
#'   latitude = Vallejo$meta$latitude,
#'   radius = 50
#' )
#'
#' if ( interactive() ) {
#'   monitor_dygraph(Napa_Fires, title='Napa Fires in California, Oct. 2017')
#' }
#'
#' }, silent = FALSE)
#' }

monitor_dygraph <- function(
  ws_monitor,
  title = "title",
  ylab = "PM2.5 Concentration",
  tlim = NULL,
  rollPeriod = 1,
  showLegend = TRUE
) {

  # Sanity check
  if ( monitor_isEmpty(ws_monitor) ) {
    stop("ws_monitor object contains zero monitors")
  }

  # Convert tlim to POSIXct
  if ( !is.null(tlim) ) {
    dateWindow <- MazamaCoreUtils::parseDatetime(tlim, timezone = "UTC")
  } else {
    dateWindow <- NULL
  }

  # Set timezone
  tzCount <- length(unique(ws_monitor$meta$timezone))
  if (tzCount > 1) {
    warning(paste0(tzCount, " timezones found. Using UTC time."))
    tzone <- "UTC"
  } else {
    tzone <- unique(ws_monitor$meta$timezone)
  }

  # Simplify access to variables
  datetime <- ws_monitor$data$datetime

  # Create an xts from all data columns except the first which is 'datetime'
  timeseriesData <- xts::xts(ws_monitor$data[, -1], datetime, tzone = tzone)

  # Add siteNames
  # Sanity check for existence of siteName column
  # NOTE:  ws_monitor objects derived from ws_grid objects only have the monitorID column
  if ( is.null(ws_monitor$meta$siteName) ) {
    ws_monitor$meta$siteName <- ws_monitor$meta$monitorID
  }
  # Sanity check for existence of names
  siteNames <- ifelse(is.na(ws_monitor$meta$siteName),
    names(ws_monitor$data)[-1], ws_monitor$meta$siteName
  )
  names(timeseriesData) <- siteNames

  show <- ifelse(showLegend, "always", "never")

  # Create dygraph
  dygraphs::dygraph(timeseriesData, main = title, ylab = ylab) %>%
    dygraphs::dyOptions(useDataTimezone = TRUE) %>% # Always show local time
    dygraphs::dyLegend(show = show, width = 250, labelsSeparateLines = TRUE) %>%
    dygraphs::dyRangeSelector(dateWindow = dateWindow) %>%
    dygraphs::dyRoller(rollPeriod = rollPeriod)

}