根据它的密度（频率）用颜色画一个圆圈

Question

我扔过球，每次都记录球离我的距离。我可以根据球与我的距离绘制密度图。但是，我想画一个圆，其半径为最大投掷距离。

此外，我想用颜色渐变来表示球数不同频率的区域（如密度图）。

如何使用 R 实现此目的？

Answer 1

使用mtcars作为示例数据，绘制密度，然后转换为极坐标：

library(ggplot2)

ggplot(mtcars, aes(mpg)) +
  geom_density() +
  coord_polar()

Answer 2

您可以将 geom_segment 与 coord_polar 一起使用（为此您必须自己设置 pre-calculate 密度）。

library(ggplot2)
# Lets calculate frequency of how far is the ball
d <- density(chickwts$weight)
# Here x is weight (or distance for OP) and y is frequency
pd <- data.frame(distance = d$x, frequency = d$y)

ggplot(pd, aes(x = 1, xend = 2, y = distance, yend = distance, color = frequency)) +
  geom_segment(stat = "identity") +
  coord_polar() +
  scale_color_viridis_c() +
  labs(
    title = "How far is the ball",
    x = "Distance",
    y = "Distance",
    color = "Frequency"
  ) +
  theme_classic() +
  theme(axis.text.x = element_blank())

如果需要分类分组，可以使用这个：

# Check if frequency is within wanted range
pd$color <- pd$frequency > 0.002 & pd$frequency < 0.003    
ggplot(
  pd,
  aes(x = 1, xend = 2, y = distance, yend = distance, color = color)
) +
  geom_segment(stat = "identity") +
  coord_polar() +
  scale_color_viridis_d() +
  labs(
    title = "How far is the ball",
    x = "Distance",
    y = "Distance",
    color = "Frequency"
  ) +
  theme_classic() +
  theme(axis.text.x = element_blank())

根据它的密度（频率）用颜色画一个圆圈

Draw a circle with color according to it's density (frequency)

r

plot

density-plot