R/ggsenate.r

In voteogram: United States House and Senate Voting Cartogram Generators

#' Produce a Senate cartogram
#'
#' @md
#' @param vote_tally either a `pprc` object (the result of a call to [roll_call()]) or
#'     a `data.frame` of vote tallies for the senate. It expects 3 columns. `state_abbrev` : the
#'     2-letter U.S. state abbreviation; `district` : either `1` or `2` to distinguish between
#'     each senator; `party` : `R`, `D` or `ID`; `position` : `yes`, `no`, `present`, `none` for
#'     how the senator voted.
#' @return a `ggplot2` object that you can further customize with scales, labels, etc.
#' @note No "themeing" is applied to the returned ggplot2 object. You can use  [theme_voteogram()]
#'     if you need a base theme.
#' @export
#' @examples \dontrun{
#' # what you'd normally do
#' sen <- roll_call("senate", 115, 1, 110)
#' }
#'
#' # Using a saved object
#' sen <- readRDS(system.file("extdata", "sen.rds", package = "voteogram"))
#'
#' senate_carto(sen)
senate_carto <- function(vote_tally) {
  if (inherits(vote_tally, "pprc")) vote_tally <- vote_tally$votes
  if (!inherits(vote_tally, "data.frame")) stop("Needs a data.frame", call. = FALSE)

  cdiff <- setdiff(c("state_abbrev", "party", "district", "position"), colnames(vote_tally))
  if (length(cdiff) > 0) stop(sprintf("Missing: %s", paste0(cdiff, collapse = ", ")), call. = FALSE)

  vote_tally <- dplyr::mutate(vote_tally, id = sprintf("%s_%s", toupper(state_abbrev), district))
  vote_tally <- dplyr::mutate(vote_tally, fill = sprintf("%s-%s", toupper(party), tolower(position)))
  vote_tally <- dplyr::mutate(vote_tally, fill = ifelse(grepl("acant", fill), "Vacant", fill))

  plot_df <- dplyr::left_join(senate_df, vote_tally, by = "id")

  ggplot(plot_df) +
    geom_rect(
      aes(
        xmin = x,
        ymin = y,
        xmax = xmax,
        ymax = ymax,
        fill = fill
      ),
      color = "white",
      linewidth = 0.25
    ) +
    scale_y_reverse() +
    scale_fill_manual(
      name = NULL,
      values = vote_carto_fill
    ) +
    labs(x = NULL, y = NULL)
}