使用R plotly生成windrose图表

Question

我的目标是使用plotly制作风玫瑰图表，绘制5个变量（SG）的国家/地区（X1, X2, X3, X4, X5）评级。

可重现代码

library(plotly) # viz
library(tidyr)  # data munge
library(dplyr)  # data munge

# list of countries
Countries <- c("SG", "UK", "CAD", "USA", "AU")

# data 
set.seed(1)
data.frame(replicate(5, sample(0:10, 5, rep=TRUE))) %>%
    cbind(Countries) %>%
    gather(key = Variable
           , value = value
           , -Countries) ->
    df

# single country
SG <- df[df$Countries %in% c("SG"),]

# plot
plot_ly(SG
        , r = value         #radial
        , t = Variable      #angular coordinates
        , color = Variable
        , type = "area") %>%
    layout(radialaxis = list(ticksuffix = "pts")
           , orientation = 270
           , autosize = T
           , width = 500
           , height = 500
           , margin = list(l = 100
                           , r = 50
                           , b = 100
                           , t = 50
                           , pad = 0
                           , autoexpand=FALSE)) %>%
    config(displayModeBar = F, showLink = F) ->
    p
p

问题

目前我得到一张空白画布（见截图）：

更新

根据@ MLavoie的评论，需要注意的另一点是，当你绘制df时，情节不是空白画布（见下面的截图2）。但是，它似乎并不反映输入数据。例如。图中的变量X1的值为8，而数据的值为sum(df[df$Variable == "X1", "value"]) = 23。