关于如何在ggplot2中制作蜘蛛图表的想法

我正在尝试使用GGplot创建一个漂亮的蜘蛛图，但有一些东西我仍然需要修复 .

• 如果可能的话，我想在图中为圆圈着色

• 如果可能的话，还要制作一个漂亮的网格，以便标记看起来不错

• 如果可能，在情节中将位置mpg设置为"12 O CLOCK"

使绘图更好的任何其他技巧都非常受欢迎 . 我已经使用mtcars数据集进行再现 . 这是我到目前为止：

library(ggplot2) 
library(reshape2)
library(scales)

# Define a new coordinate system 
coord_radar <- function (theta = "x", start = 0, direction = 1) 
{
  theta <- match.arg(theta, c("x", "y"))
  r <- if (theta == "x") 
    "y"
  else "x"
  ggproto("CoordRadar", CoordPolar, theta = theta, r = r, start = start, 
          direction = sign(direction),
          is_linear = function(coord) TRUE)
}
is.linear.radar <- function(coord) TRUE 

# rescale all variables to lie between 0 and 1 
scaled <- as.data.frame(lapply(mtcars, ggplot2:::rescale01))

scaled$model <- rownames(mtcars)    # add model names as a variable 

as.data.frame(melt(scaled,id.vars="model")) -> mtcarsm

mtcarsm2 <- dplyr::filter(mtcarsm, model = model %in% c("Maserati Bora","Volvo 142E"))
my.color = c("red","darkgreen")

mtcarsm2$Make.color <-  ifelse(mtcarsm2$model=="Maserati Bora", "1",
                               ifelse(mtcarsm2$model=="Volvo 142E", "2",
                                      NA  ))

cols <- c("Maserati Bora" = "darkorange","Volvo 142E" = "blue")

library(scales)
library(ggthemes)

scaled <- as.data.frame(lapply(mtcars, ggplot2:::rescale01))
scaled$model <- rownames(mtcars)    # add model names as a variable
# melt the dataframe
mtcarsm <- reshape2::melt(scaled)
# plot it as using the polygon geometry in the polar coordinates
ggplot(mtcarsm2, aes(x = variable, y = value, fill=as.factor(model))) +
  geom_polygon(aes(group = model, color = model), fill = NA, size = 1) +
  coord_polar()+
  xlab("") + ylab("")+theme_minimal()+scale_colour_manual(
       values = c("Maserati Bora" = "darkorange","Volvo 142E" = "deepskyblue4"))+
  theme(panel.background = element_rect(fill = "lightblue",
                                        colour = "lightblue",
                                        size = 0.5, linetype = "solid"),
        panel.grid.major = element_line(size = 0.5, linetype = 'solid',
                                        colour = "white"), 
        panel.grid.minor = element_line(size = 0.25, linetype = 'solid',
                                        colour = "white"))

结果图片