Animating plots using gganimate

Artwork by @allisonhorst

library(tidyverse)
library(gganimate)
library(lubridate)

Storms Data

The storms dataset from the dplyr package. This dataset tracks tropical storms in the North Atlantic, including wind speed, pressure, and location over time — making it perfect for animation.

data("storms")

• name: storm name
• year, month, day, hour: timestamp info
• lat, long: geographic location
• wind: wind speed (in knots)
• pressure: atmospheric pressure (hPa)
• status: classification (tropical storm, hurricane, etc.)

Let’s animate the path of one specific storm – Katrina in 2005.

Let’s get the data in an appropriate format.

katrina <- storms %>%
  filter(name == "Katrina", year == 2005) %>%
  mutate(time = make_datetime(year, month, day, hour))

It’s usually useful to start with a static plot:

ggplot(katrina, aes(x = long, y = lat)) +
  geom_path(color = "gray") +
  geom_point(aes(size = wind, color = pressure), alpha = 0.8) +
  coord_fixed() +
  theme_minimal() +
  labs(title = "Hurricane Katrina: Wind and Pressure", x = "Longitude", y = "Latitude")

I also think it would be cool to add a map behind it. Let’s pull one from the rnaturalearth package.

library(rnaturalearth)
library(rnaturalearthdata)
library(sf)

world <- ne_countries(scale = "medium", returnclass = "sf")

plot <- ggplot() +
  # World landmasses
  geom_sf(data = world, fill = "#f0f0f0", color="#8f8d8d", linewidth = 0.3) +

  # Map bounds
  coord_sf(xlim = c(-95, -75), ylim = c(20, 40), expand = FALSE) +

  # Storm path
  geom_path(data = katrina, aes(x = long, y = lat), 
            color = "gray40", linewidth = 1, linetype = "solid") +

  # Storm points7
  geom_point(
    data = katrina,
    aes(x = long, y = lat, size = wind, color = pressure),
    alpha = 0.8
  ) +

  # Scales
  scale_color_gradient(low = "#fee08b", high = "#d73027", name = "Pressure (hPa)") +
  scale_size(range = c(2, 15), name = "Wind (knots)", breaks = c(35, 65, 100)) +

  # Labels
  labs(
    title = "Hurricane Katrina (2005)",
    x = "Longitude", y = "Latitude"
  ) +

  # Themes
  theme(
    legend.position = "right",
    panel.background = element_rect(fill = "#e6f2ff", color = NA)
  )

plot

To animate this over time, you need to add transition_time(time). It may take some time for this code to run on your computer. The animation will show up in the viewer pane on the left, instead of below the code.

plot +
  labs(
    subtitle = "Time: {frame_time}",
  ) +
  transition_time(katrina$time) +
  ease_aes("cubic-in-out")

You need to save this as a .gif file:

anim <- last_plot() %>%
  animate(width = 700, height = 500, fps = 5, renderer = gifski_renderer())

anim_save("katrina.gif", anim)

You can include this in your file using ![](katrina.gif) inside plain text.