R/plotAvgRad.R

In Simularia/simulariatools: Simularia Tools for the Analysis of Air Pollution Data

#' Plot hourly average radiation
#'
#' Plot a histogram with hourly average of solar radiation, together with
#' hourly maxima for June and December.
#'
#' @param mydata A data frame containing fields with solar radiation time
#' series.
#' @param date  Name of the column representing date and time.
#' @param rad   Name of the column representing radiation.
#' @param ylabel The label along the y axis.
#' @param title Optional plot title
#' @param locale Locale to use for legend. Default is English, the only other
#' one currently supported is italian.
#'
#' @return A \code{ggplot2} plot.
#'
#' @seealso [plotStabilityClass()], [plotAvgTemp()]
#'
#' @export
#'
#' @importFrom stats aggregate
#'
#' @examples
#' data(stMeteo)
#' plotAvgRad(stMeteo, date = "date", rad = "radg")
#'
plotAvgRad <- function(mydata, date = "date", rad = "radg",
                       ylabel = NULL, title = "", locale = NULL) {

    if (!requireNamespace("openair", quietly = TRUE)) {
        stop("Please install openair from CRAN.", call. = FALSE)
    }
    mydata <- as.data.frame(mydata)

    # Rename columns
    names(mydata)[names(mydata) == date] <- 'date'
    names(mydata)[names(mydata) == rad] <- 'rad'

    # Select datetime and radiation
    mydata <- subset(mydata, select = c(date, rad))
    mydata_dec <- openair::selectByDate(mydata, month = 12)
    mydata_jun <- openair::selectByDate(mydata, month = 6)

    means <- stats::aggregate(mydata["rad"],
                              by = format(mydata["date"], "%H"),
                              FUN = mean, na.rm = TRUE)
    max_jun <- stats::aggregate(mydata_jun["rad"],
                                format(mydata_jun["date"], "%H"),
                                FUN = max, na.rm = TRUE)
    max_dec <- stats::aggregate(mydata_dec["rad"],
                                format(mydata_dec["date"], "%H"),
                                FUN = max, na.rm = TRUE)
    means$date <- as.numeric(means$date)
    max_jun$date <- as.numeric(max_jun$date)
    max_dec$date <- as.numeric(max_dec$date)

    # Get locale if not explicitely set
    if (is.null(locale)) {
        locale <- Sys.getlocale(category = "LC_TIME")
    }

    if (grepl("it", locale)) {
        media <- "Media"
        minima <- "Massimo Dicembre"
        massima <- "Massimo Giugno"
    } else {
        media <- "Average"
        minima <- "December maximum"
        massima <- "June maximum"
    }

    v <- ggplot(data = means, aes(x = date, y = rad)) +
        geom_bar(aes(color = media, fill = media), stat = "identity", show.legend = FALSE) +
        geom_line(data = max_dec, aes(x = date, y = rad, color = minima), size = 1) +
        geom_line(data = max_jun, aes(x = date, y = rad, color = massima), size = 1) +
        scale_y_continuous(breaks = seq(0, 1000, 100)) +
        scale_x_continuous(breaks = 0:23, limits = c(0, 23)) +
        scale_color_manual(values = c("steelblue", "darkgreen", "darkorange2"),
                           breaks = c(media, minima, massima),
                           guide = guide_legend(title = NULL)) +
        scale_fill_manual(label = media, values = c("steelblue"), guide = NULL)  +
        labs(x = NULL,
             # y = expression(paste("Radiazione Globale [W/", m^{2},"]"))) +
             y = ylabel) +
        theme_bw(base_family = "sans") +
        theme(legend.position = c(0.01, 0.99),
              legend.justification = c(0, 1),
              legend.box.margin = margin(t = 0, unit = "cm"),
              panel.grid.major.x = element_blank()
        )

    return(v)
}