Data Visualization LA1

Build a circular bar plot to show percentage allocation of a government budget across sectors.

Step 1 : Load the required libraries

# Required Packages
# install.packages("ggplot2")
# install.packages("dplyr")
library(ggplot2)
library(dplyr)

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union

Step 2 : Load the required dataframe

# Circular Bar Plot of Government Budget Percentage Allocation by Sector
# Sample Data from https://www.usaspending.gov/ (Simulated)

budget_data <- data.frame(
  sector = c(
    "Health Care",
    "Defense",
    "Education",
    "Infrastructure",
    "Social Welfare",
    "Science & Technology",
    "Environment",
    "Transportation",
    "Energy",
    "Agriculture"
  ),
percentage = c(19, 26, 12, 8, 10, 6, 5, 7, 4, 3)
)

# Add id for each sector
budget_data <- budget_data %>%
  arrange(desc(percentage)) %>%
  mutate(id = row_number())

# Calculate the angle of each bar (to rotate labels accordingly)
number_of_bars <- nrow(budget_data)

angle <- 90 - 360 * (budget_data$id - 0.5) / number_of_bars   # Calculate angle for labels

budget_data <- budget_data %>%
  mutate(angle = angle,
         hjust = ifelse(angle < -90, 1, 0),  # Align labels properly
         angle = ifelse(angle < -90, angle + 180, angle))

Step 3 : Create a circular bar plot

# Plot
p <- ggplot(budget_data, aes(x = as.factor(id), y = percentage, fill = sector)) +
  geom_bar(stat="identity", color = "black", alpha=0.85) +
  ylim(-10, max(budget_data$percentage) + 10) +  # expand limits for label space
  coord_polar(start = 0) +
  geom_text(aes(label = paste0(sector, "\n", percentage, "%"), y = percentage + 3, angle = angle, hjust = hjust),
            size=4, color = "black", fontface = "bold") +
  theme_minimal() +
  theme(
    axis.text = element_blank(),
    panel.grid = element_blank(),
    axis.title = element_blank(),
    legend.position = "none",
    plot.title = element_text(hjust = 0.5, face = "bold", size = 16)
  ) +
  scale_fill_viridis_d(option = "plasma") +
  ggtitle("Government Budget Percentage Allocation by Sector")

# Print the plot
print(p)