Intro

How to create a map an animation using gganimate

1. Getting ready

Load and/or install the following packages:

library(here)
library(tidyverse)

2. Load data

library(sula)

Example<-GPS_01

3. Mark beggining

Mark a day zero to begging the animation, and the sequence to use

first(Example$DateGMT)

[1] "02/11/2017"

Example$date_diff <- as.Date(as.character(Example$tStamp), 
                             format="%Y-%m-%d")-
  as.Date(as.character('2017-11-02'), 
          format="%Y-%m-%d")

Create number sequence for animation

Example<-Example %>% 
  group_by(IDs) %>%
  mutate(Secuencia = row_number())

4. Create map for reference

For creating maps, the package sf is to be called.

library(sf)

Now load your data, here I am giving my directory, you should use the one on your computer.

To dowload the shapefile from Chile you can use this this link, this shapefile comes from the DIVA-GIS

Country<-st_read(paste0(Directory,MyShapefileName))

Reading layer `CHL_adm1' from data source 
  `C:\Users\lerma\OneDrive\Documents\03Academico\02Proyectos-Postdoc\2024\1Programming\1Distill\Distill\_posts\2023-06-01-gganimate\CHL_adm1.shp' 
  using driver `ESRI Shapefile'
Simple feature collection with 16 features and 9 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: -109.455 ymin: -55.98403 xmax: -66.41472 ymax: -17.50755
Geodetic CRS:  WGS 84

5. Plot

Plot the area of interest

My_map<-ggplot(data=Example)  + 
  geom_sf(data = Country,colour = "#edf2f4", fill = "#2b2d42",)+
  geom_point(data=Example,aes(x = Longitude, y=Latitude))+
  geom_path(data=Example,aes(x = Longitude, y=Latitude))+
  coord_sf(xlim = c(-110,-109), ylim = c(-27.5,-26.5))
My_map

6. Modify map to taste

My_map<-My_map+
 theme_bw()+

  theme(
    panel.grid.major = element_blank(), 
    panel.grid.minor = element_blank(),
    panel.background = element_rect(fill = '#edf2f4'),
    
    axis.text.x =  element_text(size=12,color = "black"),
    axis.text.y =  element_text(size=12,color = "black"),
    
    axis.ticks.x = element_line(color = "black"),
    axis.ticks.y = element_line(color = "black"),
    
    title = element_text(colour = "black"),
    legend.position = "none")+
  
    scale_x_continuous(labels = function(x) paste0(x, '\u00B0', "W")) +
    scale_y_continuous(labels = function(x) paste0(x, '\u00B0', "N"))
My_map

7. Animate

To animate this plot, we will use the package gganimate

library(gganimate)

Because animations might take some time, I like to use the package beepr to let me know when the animation is ready

library(beepr)

transition_reveal leaves the track on the back ground so you can keep record where it was

My_animation<-ggplot(data=Example)  + 
  geom_sf(data = Country,colour = "#edf2f4", fill = "#2b2d42",)+
  geom_point(data=Example,aes(x = Longitude, y=Latitude, colour = tStamp))+
  geom_path(data=Example,aes(x = Longitude, y=Latitude))+
  coord_sf(xlim = c(-110,-109), ylim = c(-27.5,-26.5))+
  
  theme_bw()+

  theme(
    panel.grid.major = element_blank(), 
    panel.grid.minor = element_blank(),
    panel.background = element_rect(fill = '#edf2f4'),
    
    axis.text.x =  element_text(size=12,color = "black"),
    axis.text.y =  element_text(size=12,color = "black"),
    
    axis.ticks.x = element_line(color = "black"),
    axis.ticks.y = element_line(color = "black"),
    
    title = element_text(colour = "black"),
    legend.position = "none")+
  
    scale_x_continuous(labels = function(x) paste0(x, '\u00B0', "W")) +
    scale_y_continuous(labels = function(x) paste0(x, '\u00B0', "N")) +
  
  transition_reveal(along=tStamp) +
  shadow_trail(distance = 0.01,
               alpha = 0.5,
               shape = 1)
My_animation

Other arguments are:
transition_time use the information for the transition is labs shows the title with time so you can use as a reference
shadow_wake is the wake behind the points read more here

8. Export

The package animation allows to save the animation as a file

library(animation)

To export, you can save the animation as gif

anim_save("animation.gif",My_animation)
beep(sound=1,expr=NULL)

Or transform from gif to mp4 using the package av

library(av)

av::av_encode_video("animation.gif", 
                    framerate = 5 ,
                    output = 'animation.mp4')
beep(sound=1,expr=NULL)

gganimate