我想使用 gganimate 来转换雷达图中的状态。
考虑以下来自 Curycu 在 Stack Overflow 上的帖子中的示例：
library(dplyr)
library(data.table)
library(ggplot2)
rm(list=ls())
scale_zero_to_one <-
function(x) {
r <- range(x, na.rm = TRUE)
min <- r[1]
max <- r[2]
(x - min) / (max - min)
}
scaled.data <-
mtcars %>%
lapply(scale_zero_to_one) %>%
as.data.frame %>%
mutate(car.name=rownames(mtcars))
plot.data <-
scaled.data %>%
melt(id.vars='car.name') %>%
rbind(subset(., variable == names(scaled.data)[1]))
# create new coord : inherit coord_polar
coord_radar <-
function(theta='x', start=0, direction=1){
# input parameter sanity check
match.arg(theta, c('x','y'))
ggproto(
NULL, CoordPolar,
theta=theta, r=ifelse(theta=='x','y','x'),
start=start, direction=sign(direction),
is_linear=function() TRUE)
}
plot.data %>%
ggplot(aes(x=variable, y=value, group=car.name, colour=car.name)) +
geom_polygon(aes(fill=car.name), alpha=0.2) +
geom_point(size=rel(0.9)) +
coord_radar() +
facet_wrap(~ car.name, nrow=4) +
theme_bw() +
theme(
axis.title.y = element_blank(),
axis.text.y = element_blank(),
axis.ticks.y = element_blank(),
axis.title.x = element_blank(),
legend.position = 'none') +
labs(title = "Cars' Status")
这为每辆车产生了惊人的多面图。我对原始代码进行了轻微修改，并将其更改geom_path为geom_polygon.
我不想使用多面图，而是将绘图显示为单个图表，该图表通过car.name. 但是，使用transition_states会产生错误：
plot.data %>%
ggplot(aes(x=variable, y=value, group=car.name, colour=car.name)) +
geom_polygon(aes(fill=car.name), alpha=0.2) +
geom_point(size=rel(0.9)) +
coord_radar() +
transition_states(car.name, transition_length = 3, state_length = 6) +
enter_grow() +
exit_shrink() +
ease_aes('sine-in-out') +
theme_bw() +
theme(
axis.title.y = element_blank(),
axis.text.y = element_blank(),
axis.ticks.y = element_blank(),
axis.title.x = element_blank(),
legend.position = 'none') +
labs(title = "Cars' Status")
错误：
Error in transform_polygon(all_frames, next_state, ease, params$transition_length[i], :
transformr is required to tween polygons
该问题并非特定于 geom_polygon，因为将其替换为 geom_path 会产生类似的错误。有没有办法修改它以使其工作？