Umfragen & Wahlergebnisse [Brandenburg, Germany]

chart_elections_brandenburg.r

library(rvest)
library(dplyr)
library(ggplot2)
library(tidyr)
library(scales)

sf <- 2
width <- 600 * sf
height <- 335 * sf

options(vsc.dev.args = list(width = width, height = height, res = 72 * sf))

custom_colors <- c(
  "CDU"     = "#000000",
  "SPD"     = "#E3000F",
  "GRÜNE"   = "#64BC5C",
  "FDP"     = "#FFCC00",
  "LINKE"   = "#BE3075",
  "AfD"     = "#0C1C8C",
  "BVB/FW"  = "#f49800",
  "BSW"     = "#792350"
)

url <- "https://www.wahlrecht.de/umfragen/landtage/brandenburg.htm"
webpage <- read_html(url)
tables <- html_table(webpage, fill = TRUE)

process_table <- function(tbl, rows_to_remove) {
  tbl |>
    select(4, 6:(ncol(tbl) - 1)) |>
    slice(-rows_to_remove) |>
    mutate(
      Datum = as.Date(Datum, format = "%d.%m.%Y"),
      across(
        -Datum,
        ~ as.numeric(gsub(",", ".", gsub(" %", "", .))) / 100
      )
    )
}

ts1 <- process_table(tables[[2]], c(1, 2))
ts2 <- process_table(tables[[3]], 1:5)

ts <- bind_rows(ts1, ts2) |>
  pivot_longer(cols = -Datum, names_to = "Partei") |>
  filter(Partei != "PIRATEN") |>
  mutate(Partei = factor(Partei, levels = names(custom_colors)))

# Create the plot
chart <- ggplot(
  ts |> filter(Datum > as.Date("2014-01-01")),
  aes(x = Datum, y = value, color = Partei, fill = Partei)
) +
  geom_smooth(method = "loess", alpha = 0.2) + # Confidence intervals with matching fill
  geom_point(size = 0.1) + # Scatter points
  scale_y_continuous(labels = percent_format(scale = 100)) + # Y-axis as percentages
  scale_color_manual(values = custom_colors) + # Set line colors
  scale_fill_manual(values = custom_colors) + # Set fill colors for confidence intervals
  labs(
    x = "Jahr",
    y = "Stimmenanteil",
    title = "Umfragen & Wahlergebnisse [Brandenburg]",
    subtitle = "Quelle: wahlrecht.de, @USMortality",
    color = "Partei",
    fill = "Partei"
  ) +
  theme_minimal() + # A clean theme
  theme(
    axis.text.x = element_text(angle = 45, hjust = 1),
    legend.position = "right"
  )

ggplot2::ggsave(
  filename = "chart1.png", plot = chart, width = width, height = height,
  units = "px", dpi = 72 * sf, device = grDevices::png, type = c("cairo")
)

https://www.mortality.watch/charts/list.html#umfragen--wahlergebnisse-brandenburg-germany