Skill: Area Chart (R)

Category

DataOverTime

When to Use

An area chart is a line chart in which the area below the line is filled with color. It is mainly used to display values at continuous intervals or over a time span.

Required R Packages

• dygraphs
• ggpattern
• hrbrthemes
• tidyverse
• viridis
• xts

Minimal Reproducible Code

# Load packages
library(dygraphs)
library(ggpattern)
library(hrbrthemes)
library(tidyverse)
library(viridis)
library(xts)

# Prepare data
# TCGA-BRCA.survival.tsv
tcga_brca_survival <- readr::read_tsv("https://bizard-1301043367.cos.ap-guangzhou.myqcloud.com/TCGA-BRCA.survival.tsv")

tcga_brca_filtered <- tcga_brca_survival %>%
  filter(OS.time <= 2000) %>%
  mutate(month = floor(OS.time / 30))

monthly_death_counts <- tcga_brca_filtered %>%
  filter(OS == 1) %>%
  group_by(month) %>%
  summarise(deaths = n())

# AirPassengers
data("AirPassengers")
air_passenger_data <- as.data.frame(AirPassengers)

air_passenger_data$Month <- rep(month.name, 12)
air_passenger_data$Year <- rep(1949:1960, each=12)
air_passenger_data$x <- as.numeric(air_passenger_data$x)

air_passenger_long <- air_passenger_data %>%
  gather(key = "Variable", value = "Value", -Year, -Month)

air_passenger_percentage <- air_passenger_long %>%
  group_by(Year) %>%
  mutate(Percentage = Value / sum(Value) * 100) # Calculate the percentage for each month

air_passenger_time_series <- data.frame(datetime = time(AirPassengers), count = as.vector(AirPassengers))

air_passenger_time_series$datetime <- as.Date(air_passenger_time_series$datetime)
air_passenger_xts <- xts(x = air_passenger_time_series$count, order.by = air_passenger_time_series$datetime) # Creating an XTS object

# Create visualization
# Basic area plot
p <- ggplot(monthly_death_counts, aes(x = month, y = deaths)) +
  geom_area() +
  labs(title = "Cumulative Deaths Over Time",
       x = "Months",
       y = "Number of Deaths")

p

Key Parameters

• x: Maps Year to the x aesthetic
• y: Maps Percentage to the y aesthetic
• fill: Maps Month to the fill aesthetic
• alpha: Controls transparency (0 = fully transparent, 1 = opaque)
• width: Controls element width
• theme: Plot theme; tutorial uses theme_ipsum()

Tips

• Use theme_minimal() or theme_bw() for clean, publication-ready plots
• Customize color scales with scale_fill_manual() or scale_color_brewer()
• Highlight key time points or events with vertical reference lines or annotations

Full Tutorial

https://openbiox.github.io/Bizard/DataOverTime/AreaChart.html