How to draw the majority threshold

Majority thresholds

The majority threshold marks the point where one group has half or more than half of the seats in parliament. To draw the majority threshold on a parliament plot, the user should input the number that constitues a majority as well as the type of parliament. The function plots a line through the majority seat. By default, the majority threshold adds an annotation noting the seats required for a government to form. This can be turned off by writing label = FALSE.

Some examples are as follows:

usa_12 <- election_data %>%
  filter(country == "USA" &
           house == "Representatives" & 
           year == "2012")  %>% 
  parliament_data(election_data = .,
  party_seats = .$seats,
  parl_rows = 8,
  type = "semicircle")

ggplot(usa_12, aes(x, y, colour = party_short)) +
  geom_parliament_seats() + 
  geom_highlight_government(government == 1) + 
  draw_majoritythreshold(n = 218,
                         type = "semicircle") + 
  theme_ggparliament() +
  labs(colour = NULL, 
       title = "2012 American Congress",
       subtitle = "Party that controls the chamber is highlighted in black.") +
  scale_colour_manual(values = usa_12$colour, 
                      limits = usa_12$party_short) 
#> Warning in ggplot2::geom_segment(ggplot2::aes(y = 0.8, yend = max(plot$data$y) + : All aesthetics have length 1, but the data has 435 rows.
#> ℹ Please consider using `annotate()` or provide this layer with data containing
#>   a single row.

#get the data for the last election
uk_data <- election_data %>%
  filter(country == "UK") %>%
  filter(year == 2017) %>%
  #parl_data it out
  parliament_data(election_data = .,
                  party_seats = .$seats,
                  group = .$government,
                  parl_rows = NULL,
                  type = "opposing_benches")
#note that for opposing benches, parliament_data tries to calculate a number of rows per dot
#that allows clear visualisation of the majority line
#try to use a number of rows that is an exact divisor of the threshold

colscale = 

#plot it
uk <- ggplot(uk_data, aes(x, y, colour = party_short)) +
  scale_colour_manual(values = unique(uk_data$colour),
                      limits = unique(uk_data$party_short),
                      name = "Party") +
  geom_parliament_seats(size = 1.5) +
  draw_majoritythreshold(n = 325, type = "opposing_benches") +
  coord_flip() + 
  theme_ggparliament() +
  theme(legend.position = c("bottom"))

uk
#> Warning in ggplot2::geom_segment(aes(y = y_pos_oppbenches + 0.5, yend = y_pos_oppbenches + : All aesthetics have length 1, but the data has 649 rows.
#> ℹ Please consider using `annotate()` or provide this layer with data containing
#>   a single row.

australia <- election_data %>%
  filter(country == "Australia" &
    house == "Representatives" &
    year == 2016) 

australia1 <- parliament_data(election_data = australia,
  party_seats = australia$seats,
  parl_rows = 4,
  type = "horseshoe")

au <-ggplot(australia1, aes(x, y, colour = party_short)) +
  geom_parliament_seats() + 
  geom_highlight_government(government == 1) + 
  draw_majoritythreshold(n = 76,
                         type = "horseshoe") + 
  theme_ggparliament() +
  labs(colour = NULL, 
       title = "Australian Parliament",
       subtitle = "Government encircled in black.") +
  scale_colour_manual(values = australia$colour, 
                      limits = australia$party_short) + 
  theme(legend.position = 'bottom') 
au
#> Warning in ggplot2::geom_segment(ggplot2::aes(y = 7.5, yend = 10.5, x = 0, : All aesthetics have length 1, but the data has 150 rows.
#> ℹ Please consider using `annotate()` or provide this layer with data containing
#>   a single row.

germany <- election_data %>%
  filter(year == 2017 & 
           country == "Germany") 

germany <- parliament_data(election_data = germany, 
                           parl_rows = 12,
                           party_seats = germany$seats, 
                           plot_order = germany$government,
                           type = 'semicircle')

german_parliament <- ggplot(germany, aes(x, y, colour = party_short)) +
  geom_parliament_seats() +
  geom_highlight_government(government == 1) + 
  draw_majoritythreshold(n = 355, label = FALSE, type = "semicircle") + 
  labs(colour="Party", 
       title="Germany 2017 Election Results") + 
  theme_ggparliament() +
  scale_colour_manual(values = germany$colour, 
                      limits = germany$party_short)
german_parliament
#> Warning in ggplot2::geom_segment(ggplot2::aes(y = 0.8, yend = max(plot$data$y) + : All aesthetics have length 1, but the data has 709 rows.
#> ℹ Please consider using `annotate()` or provide this layer with data containing
#>   a single row.

Zoe Meers

2024-05-19