R/wtss_plot.R

In wtss: An R Client for Web Time-Series Service

#' @title  Generic interface for ploting time series
#' @method plot wtss
#' @name plot
#' @author Gilberto Camara, \email{gilberto.camara@@inpe.br}
#' @description Given a tibble with a set of time series, plot them.
#'
#'
#' @param  x            object of class "wtss"
#' @param  y            ignored
#' @param ...           further specifications for \link{plot}.
#' @param  colors       Color pallete to be used (based on Color Brewer - 
#'                      default is "Dark2").
#' @return              Input  tibble (useful for chaining functions).
#'
#' @examples{
#' # Read one time series from the WTSS server
#' # plot one time series
#' wtss <- wtss::WTSS("http://www.esensing.dpi.inpe.br/wtss/")
#' ts   <- wtss::time_series(wtss, name = "MOD13Q1", 
#'                 attributes = c("ndvi","evi"), 
#'                 longitude = -45.00, latitude  = -12.00,
#'                 start_date = "2000-02-18", end_date = "2016-12-18")
#' plot(ts)
#' }
#' @export
plot.wtss <- function(x, y, ..., colors = "Dark2") {
    
    data <- tibble::as_tibble(x)
    purrr::map(list(data), function(row) .wtss_ggplot_series(row, colors))
    # return the original tibble - useful for chaining
    return(invisible(data))
}
#' @title Plot one timeSeries using ggplot
#'
#' @name .wtss_ggplot_series
#'
#' @description Plots a set of time series using ggplot. This function is used
#' for showing the same lat/long location in a series of time steps.
#'
#' @param row         A row of a sits tibble with the time series to be plotted.
#' @param colors      The set of Brewer colors to be used for plotting.
.wtss_ggplot_series <- function(row, colors = "Dark2") {
    # create the plot title
    plot_title <- paste("Location = (", row$latitude,  ", ", row$longitude, ")",
                        sep = "")
    #extract the time series
    data.ts <- row$time_series
    # melt the data into long format
    melted.ts <- data.ts %>%
        reshape2::melt(id.vars = "Index") %>%
        as.data.frame()
    # plot the data with ggplot
    g <- ggplot2::ggplot(melted.ts, 
                         ggplot2::aes(x = Index, y = value, group = variable)) +
        ggplot2::geom_line(ggplot2::aes(color = variable)) +
        ggplot2::labs(title = plot_title) +
        ggplot2::scale_color_brewer(palette = colors)
    graphics::plot(g)
    return(g)
}