How to create smooth transition between states in gganimate using geom_point? - r

Question

I am trying to create an animated plot using gganimate.
When I pass the following factor dat$period to transition_states,
I get 3 static images. I would prefer to have the points "move" from state-to-
state.
Here is my code:
plot <-
ggplot(data = dat, aes(x = age, y = value, color = period)) +
geom_point(size = 3, aes(group = period)) +
facet_wrap(~group)+
transition_states(states=period, transition_length = 2, state_length = 1) +
ease_aes('linear')+
enter_fade()+
exit_fade()
plot
Here is my data:
record period value age group
1 1 start 45 24 a
2 2 start 6 22 c
3 3 start 23 32 b
4 4 start 67 11 a
5 1 middle 42 24 a
6 2 middle 65 22 c
7 3 middle 28 32 b
8 4 middle 11 11 a
9 1 end 23 24 a
10 2 end 14 22 c
11 3 end 34 32 b
12 4 end 21 11 a
13 5 start 5 12 c
14 6 start 9 23 c
15 7 start 53 47 b
16 8 start 17 32 a
17 5 middle 15 12 c
18 6 middle 6 23 c
19 7 middle 23 47 b
20 8 middle 67 32 a
21 5 end 51 12 c
22 6 end 16 23 c
23 7 end 8 47 b
24 8 end 41 32 a
The points appear/disappear - I would like the points to travel on the screen between states - any help appreciated

Answer 1

The group aesthetic is used to determine which rows in each period's data are treated as the same objects. You need group = record here:
ggplot(data = dat, aes(x = age, y = value, color = period)) +
geom_point(size = 3, aes(group = record)) +
facet_wrap(~ group)+
transition_states(states=period, transition_length = 2, state_length = 1) +
ease_aes('linear')+
enter_fade()+
exit_fade()