Update gganimate to new API and add complexity

Author: ethanwhite

materials/gganimate.md

@@ -5,64 +5,79 @@ title: gganimate
 language: R
 ---
 
-> * ImageMagick needs to be installed to save as gif (the default)
-> * Save to html file if installing ImageMagick isn't an option
->     * E.g., gganimate(p, "output.html")
-
 ### Installation
 
-* Some R packages are not published to CRAN
-* Can install from other places using `devtools`
-
-```
-install.packages("devtools")
-devtools::install_github("dgrtwo/gganimate")
+```r
+# gifski required for default gif output
+install.packages(c("gganimate", "gifski", "rnoaa"))
 ```
 
 ### Example
 
 * Example using weather data
 * Get this data using `rnoaa`
 
+```r
+library(gganimate)
+library(ggplot2)
+library(lubridate)
+library(rnoaa)
+
+gnv_weather <- meteo_pull_monitors("USW00012816", date_min = "1984-01-01", date_max = "2024-12-31")
 ```
-install.packages('rnoaa')
-library('rnoaa')
-gnv_weather <- meteo_pull_monitors("USW00012816", date_min = "1984-01-01", date_max = "2016-12-31")
-```
+
 * Plot annual temperature pattern through time
 * First make a plot of the annual temperature trend using ggplot
 
+```r
+gnv_weather$year = as.integer(year(gnv_weather$date))
+gnv_weather$jday = yday(gnv_weather$date)
+gnv_weather$tmax = gnv_weather$tmax / 10
+
+ggplot(gnv_weather, aes(x = jday, y = tmax)) +
+  geom_line()
 ```
-library(ggplot2)
-library(gganimate)
 
-gnv_weather$year = format(gnv_weather$date, "%Y")
-gnv_weather$jday = as.numeric(format(gnv_weather$date, "%j"))
+* This plot shows the temperatures of each day of the year for all years from 1984 to 2024
+* Let's animate them so we can see the pattern over time
+
+* Add `transition_time` element to
 
-ggplot(gnv_weather, aes(x = jday, y = tmax / 10)) +
-  geom_point()
+```r
+ggplot(gnv_weather, aes(x = jday, y = tmax)) +
+  geom_line() +
+  transition_time(year)
 ```
 
-* Then add `frame` element to `aes()`
+* Now let's add some information on year to the graph
+* Do this by adding a title that shows the time (in our case year) for each frame
 
+```r
+ggplot(gnv_weather, aes(x = jday, y = tmax)) +
+  geom_line() +
+  labs(title = 'Year: {frame_time}') +
+  transition_time(year)
 ```
-p <- ggplot(gnv_weather, aes(x = jday, y = tmax / 10, frame = year)) +
-  geom_point()
 
-gganimate(p)
+* Add a shadow mark to the plot so that we can see where previous years were
+
+```r
+ggplot(gnv_weather, aes(x = jday, y = tmax)) +
+  geom_line() +
+  labs(title = 'Year: {frame_time}') +
+  transition_time(year) +
+  shadow_mark(color = 'gray', linewidth = 0.2)
 ```
 
-* Uses the `animation` package
-* More complicated but more powerful
+* If we want more control over the animation store the ggplot object and use `animate()`
 
-```
-install.packages('animation')
-library(animation)
-
-saveGIF({
-  for (yr in 1984:2016){
-    data = dplyr::filter(gnv_weather, year == yr)
-    plot(data$jday, data$tmax)
-  }
-})
+```r
+p <- ggplot(gnv_weather, aes(x = jday, y = tmax)) +
+  geom_line() +
+  labs(title = 'Year: {frame_time}') +
+  transition_time(year) +
+  shadow_mark(color = 'gray', linewidth = 0.2) +
+  ease_aes('linear')
+
+animate(p, fps = 2, end_pause = 50)
 ```