R/utils.R

In antaldaniel/satellitereport: SatelliteReport Helper Functions

#' Check dat input parameter
#'
#' @param dat Eurostat data frame or a data frame derived from
#'  \code{create_indicator} or \code{create_tables}.
#' @param geo_var The name of the variable that contains the standard
#' \code{geo} codes. It defaults to \code{"geo"}.
#' @param values_var The name of the variable that contains the
#' \code{values} To be mapped. It defaults to \code{"values"}. If the data
#' you want to see on map is in the column \code{average_values}, than
#' use  \code{"average_values"}. The values can be numeric or categorical
#' variables.
#' @return The function does not return a value, but creates a meaningful
#' error message if the dat parameter is non-conforming.
#' @keywords internal

check_dat_input <- function(dat, geo_var, values_var) {

  if ( ! "data.frame" %in% class(dat) ) {
    stop ("Parameter 'dat' must be a data.frame-like object.")
  }

  if ( ! values_var %in% names(dat) ) {
    stop ("Parameter values_var='", values_var, "' is not present in 'dat'")
  }

  if ( ! geo_var %in% names(dat) ) {
    stop ("Parameter geo_var='", geo_var, "' is not present in 'dat'")
  }
}

#' Create a numeric choropleth
#'
#' @param choropleth_data An sf object with the numerical data in column
#' \code{values}.
#' @param min_color A color for the minimum values.
#' @param max_color A color for the maximum values.
#' @param na_color Defaults to \code{"grey93"}. This color will be used
#' in the color palette for missing values, unless you have explicitly
#' set one of the names of the palette to \code{"missing"}.
#' @param unit_text Defaults to \code{NULL}. The title caption of the
#' color (fill) legend.
#' @param iceland A logical variable to show Iceland on the map.
#' @return A ggplot object containing the choropleth map.
#' @keywords internal
#' @importFrom magrittr `%>%`
#' @importFrom grDevices colorRampPalette
#' @importFrom ggplot2 ggplot aes geom_sf
#' @importFrom ggplot2 scale_fill_continuous scale_fill_gradient
#' @importFrom ggplot2 labs theme_light theme guides coord_sf
#' @importFrom ggplot2 element_blank xlim ylim guide_legend

create_base_plot_num <- function (choropleth_data,
                                  min_color,
                                  max_color,
                                  na_color,
                                  unit_text,
                                  iceland) {
  . <- values <- NULL

  base_plot_num <- choropleth_data  %>%
    ggplot2::ggplot(data=.) +
    ggplot2::geom_sf(data=.,
                     ggplot2::aes(fill=values),
                     color="white", size=.05) +
    ggplot2::scale_fill_continuous(
      ggplot2::scale_fill_gradient(low =  min_color,
                                   high = max_color,
                                   na.value = na_color )
    ) +
    ggplot2::guides(fill = ggplot2::guide_legend(reverse=FALSE,
                                                 title = unit_text)) +
    ggplot2::theme_light() +
    ggplot2::theme(legend.position='right',
                   axis.text = element_blank(),
                   axis.ticks = element_blank())

  if ( iceland ) {
    p <- base_plot_num  +
      ggplot2::coord_sf(xlim = c(-23,34),
                        ylim = c(34.5,71.5))
  } else {
    p <- base_plot_num  +
      ggplot2::coord_sf(xlim = c(-11.7, 32.3),
                        ylim = c(34.5,71.5))
  }

}

#' Create a categorical choropleth
#'
#' @param choropleth_data An sf object with the categorical data in column
#' \code{cat}.
#' @param color_palette A named character vector with colors. If you use this
#' with categorical variables, make sure that the color_palette has a value
#' for each categories except for missing values, and it is named to the
#' category name (factor level) as it is found in you \code{values_var}.
#' @param na_color Defaults to \code{"grey93"}. This color will be used
#' in the color palette for missing values, unless you have explicitly
#' set one of the names of the palette to \code{"missing"}.
#' @param iceland A logical variable to show Iceland on the map.
#' @param unit_text Defaults to \code{NULL}. The title caption of the
#' color (fill) legend.
#' @param drop_levels Weather to drop categorical levels on the choropleth
#' if they are not present in the data. Defaults to \code{FALSE}.
#' @param are_there_missings A logical variable if missing data is present.
#' @keywords internal
#' @return A ggplot object containing the choropleth map.
#' @importFrom magrittr `%>%`
#' @importFrom grDevices colorRampPalette
#' @importFrom ggplot2 ggplot aes geom_sf
#' @importFrom ggplot2 scale_fill_manual scale_fill_gradient
#' @importFrom ggplot2 labs theme_light theme guides coord_sf
#' @importFrom ggplot2 element_blank xlim ylim guide_legend

create_base_plot_cat <- function(choropleth_data,
                                 color_palette,
                                 na_color,
                                 drop_levels,
                                 iceland,
                                 are_there_missings,
                                 unit_text) {

  base_plot_cat <- ggplot2::ggplot(data=choropleth_data)

  base_plot_cat <- base_plot_cat +
    ggplot2::geom_sf( data= choropleth_data,
                      ggplot2::aes(fill=cat),
                      color="white", size=.05
    )  +
    ggplot2::guides(fill = ggplot2::guide_legend(reverse=FALSE,
                                                 title = unit_text)) +
    ggplot2::theme_light() +
    ggplot2::theme(legend.position='right',
                   axis.text = ggplot2::element_blank(),
                   axis.ticks = ggplot2::element_blank())

  #plot ( base_plot_cat)

  if (are_there_missings) {
    base_plot_cat <-  base_plot_cat +
      ggplot2::scale_fill_manual(values = color_palette,
                                 na.value = na_color,
                                 drop = drop_levels)
  } else {
    base_plot_cat <-  base_plot_cat +
      ggplot2::scale_fill_manual(values = color_palette,
                                 breaks = names(color_palette),
                                 drop = drop_levels )
  }

  if ( iceland ) {
    p <- base_plot_cat  +
      ggplot2::coord_sf(xlim = c(-23,34),
                        ylim = c(34.5,71.5))
  } else {
    p <- base_plot_cat  +
      ggplot2::coord_sf(xlim = c(-11.7, 32.3),
                        ylim = c(34.5,71.5))
  }

  p
}