A new R packge (

`gganimate`

) provides some new features for animation in R. Its big advantage is it could make use of ggplot API and embeded into ggplot. Next, I will use a sample data to show the example. Then I will use some real educational data to explore a little bit what we can do in psychometric area.

# A Simple Example

I want to introduce this package.

## 1.0 Load the packages requried

## 1.1 prepare the data

```
data("austres")
dt <- data.frame(x=as.matrix(austres), date=time(austres))
dt$y <- rnorm(nrow(dt))
dt$date <- as.numeric(dt$date)
```

```
p <- ggplot(dt,
aes(y = y, x =x)) +
geom_line(alpha = 0.7) +
geom_point()
p
```

`transition_reveal`

: gradually reveal the data

`p + transition_reveal(date)`

`dt$g <- rep( c("red", "green", "blue"), length.out = nrow(dt))`

```
p_bygroup <- ggplot(dt,
aes(y = y, x =x, col = g)) +
geom_line(alpha = 0.7) +
geom_point()
p_bygroup
```

`p_bygroup + transition_reveal(date)`