Create animation or GIF with point plots in R

Question

I am trying to create an animation or GIF that shows the evolution of an environmental condition over time. Basically, I have a dataset (example below) with year, value of the environmental condition, unit, and coordinates.

year	condition	unit	Lat	Long
1945	-0.120148	TSS	41.36531	41.67889
1948	0.274646	TSS	30.45368	-87.99042
1948	0.074794	TSS	30.45368	-87.99042
1975	-0.102050	TSS	38.10541	-122.06782
1979	-0.169886	NTU	29.77048	-84.91630

I am using ggplot2 to create the plots comprising year gaps. Here is the code I am using to plot the variation from 1945 to 1980:

`ggplot() +
  geom_map(data = world, map = world,aes(long, lat, map_id = region),color = "seashell2", fill = "seashell", size = 0.3, alpha=0.9)+
  geom_point(data = mapa_variacao_anual_45_80,aes(Long, Lat, color = med_turb),size=2, shape=16, position = position_jitter(width = 8)) + 
  labs(title = "1945 to 1980")+
  theme(plot.title = element_text(hjust = 0.5))+
  scale_colour_gradient( low = "darkgreen",    high = "red")+
  xlab("Longitude") + ylab("Latitude")+
  theme(legend.title= element_blank())+
  theme(panel.background = element_rect(fill = 'aliceblue', colour = 'gray'))`

My plan is to have several plots with determined year ranges and in the end combine all of them in sequence to show temporal variation. Is there an easy way to combine the plots? I have been looking for solutions online but they seem not to suit my goal or are just too complicated.

Thanks in advance for any help.

Answer 1

You could get gganimate to handle the animation for you:

library(ggplot2)
library(gganimate)

world <- map_data("world")

p <- ggplot() +
  geom_map(data = world, map = world,
           aes(long, lat, map_id = region),
           color = "seashell2", fill = "seashell", size = 0.3, alpha = 0.9)+
  geom_point(data = mapa_variacao_anual_45_80, 
             aes(Long, Lat, color = med_turb),
             size = 2, shape = 16, position = position_jitter(width = 8)) + 
  labs(title = "1945 to 1980")+
  theme(plot.title = element_text(hjust = 0.5))+
  scale_colour_gradient( low = "darkgreen", high = "red") +
  xlab("Longitude") + 
  ylab("Latitude")+
  theme(legend.title= element_blank())+
  theme(panel.background = element_rect(fill = 'aliceblue', colour = 'gray')) +
  transition_events(seq(nrow(mapa_variacao_anual_45_80)) ,
                    enter = 1L, exit = 1L) +
  enter_fade() +
  exit_fade()

anim_save("map.gif", p, device = "ragg_png", duration = 3, fps = 30,
          width = 900, height = 450)

Answer 2

You can create a series of png files and assemble them into an animation with the gifski package:

library(ggplot2)
library(gifski)

for(i in 1:30){
  gg <- ggplot(......)
  ggsave(sprintf("myplot%03d.png", i), gg)
}

png_files <- Sys.glob("myplot*.png")

gifski(
  png_files,
  "myanimation.gif",
  width = 400, height = 400,
  delay = 1/5 # 5 images per second
)

file.remove(png_files)