绘制不同ymin和ymax的重叠几何图形

可能可以使用填充和alpha的某种组合来显示底层重叠。这是一个主意:

ggplot(df %>%
         mutate(n = 1:n()),
       aes(xmin = start,
           ymin = as.numeric(chr) - 0.1,
           xmax = stop,
           ymax = as.numeric(chr) + 0.1)) +
  xlab("position") +
  geom_rect(color = "black", alpha = 0.5) +
  scale_y_continuous(breaks = c(1, 2),
                     labels = levels(df$chr))+
  theme(legend.position = "none",
        text = element_text(size = 10)) +
  theme_bw() 

区域越暗,重叠越多。如果重叠很少,这可能很方便,但如果有很多重叠,我会强调如下:

ggplot(df %>%
         group_by(chr) %>%
         mutate(n = 1:n()),
       aes(xmin = start,
           ymin = n - 0.5,
           xmax = stop,
           ymax = n + 0.5)) +
  xlab("position") +
  geom_rect(color = "black", alpha = 0.5) +
  facet_wrap(~chr, ncol = 1, strip.position = "right")+
  theme_bw() +
  theme(legend.position = "none",
        axis.text.y = element_blank(),
        axis.ticks.y = element_blank())

structure(list(chr = structure(c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 
2L), .Label = c("a", "b"), class = "factor"), start = c(3L, 6L, 
5L, 12L, 6L, 3L, 2L, 2L), stop = c(7L, 8L, 10L, 14L, 8L, 8L, 
5L, 5L)), .Names = c("chr", "start", "stop"), class = "data.frame", row.names = c(NA, 
-8L))