geom_violin重叠图

Question

默认情况下，如果最宽点出现在相同高度，相邻小提琴将在最宽点处相互接触。我想让我的小提琴图更宽，以便它们相互重叠。基本上，更类似于山脊情节：

这可以用geom_violin吗？

我看到width参数，但如果我将其设置为高于1，我会收到这些警告，这让我认为这可能不是最合适的方法：

Warning: position_dodge requires non-overlapping x intervals

Answer 1

我不认为geom_violin是通过设计来实现的，但我们可以通过一些努力来破解它。

使用ggplot2中钻石数据集的插图：

# normal violin plot
p1 <- diamonds %>%
  ggplot(aes(color, depth)) +
  geom_violin()

# overlapping violin plot
p2 <- diamonds %>%
  rename(x.label = color) %>% # rename the x-variable here; 
                              # rest of the code need not be changed
  mutate(x = as.numeric(factor(x.label)) / 2) %>%
  ggplot(aes(x = x, y = depth, group = x)) +

  # plot violins in two separate layers, such that neighbouring x values are
  # never plotted in the same layer & there's no overlap WITHIN each layer
  geom_violin(data = . %>% filter(x %% 1 != 0)) +
  geom_violin(data = . %>% filter(x %% 1 == 0)) +

  # add label for each violin near the bottom of the chart
  geom_text(aes(y = min(depth), label = x.label), vjust = 2, check_overlap = TRUE) +

  # hide x-axis labels as they are irrelevant now
  theme(axis.text.x = element_blank(),
        axis.ticks.x = element_blank())

gridExtra::grid.arrange(
  p1 + ggtitle("Normal violins"),
  p2 + ggtitle("Overlapping violins"),
  nrow = 2
)