在不同级别绘制刻度线

Question

我想知道是否可以将刻度标签放在两个不同的级别以避免标签之间重叠。例如这里：

a=c[1:10]
b=c("January","February","March","April","May","June","July","August","September","October")
barplot(a,space=0,axes=F)
ticks=a
axis(side=1, at =ticks, labels=b)

Answer 1

您可以尝试以下方法：

a=1:10
b=c("January","February","March","April","May","June","July","August","September","October")
barplot(a,space=0,axes=F)
ticks=a

# indices of even ticks
idx <- seq(2, length(ticks), 2) 

# b2 only contains the odd labels.
b2 <- b
# Empty space so a small line gets drawn at omitted labels
b2[idx] <- ""

# draw odd labels
axis(side=1, at =ticks, labels=b2, line = 0)
# same command for even ticks, lwd = 0 suppresses drawing the x-axis twice
axis(side=1, at =ticks[idx], labels=b[idx], line = 1, lwd = 0)

这基本上通过先在奇数位置绘制标签，然后在偶数位置绘制标签来避免重叠，但由于 line = 1 而略低。

Answer 2

您可以尝试进行两次 axis 调用，一次用于奇数月份，一次用于偶数月份，然后将它们放在不同的 line 上。第一个 axis 调用只是绘制刻度线，没有标签。

a=1:10
a_even <- a[a %% 2==0]
a_odd <- a[a %% 2==1]
b=c("January","February","March","April","May","June","July","August","September","October")
barplot(a,space=0,axes=F)
ticks=a
axis(side=1, at =ticks, labels=FALSE,line = 1)
axis(side=1, at =ticks[a_odd], labels=b[a_odd],line = 1,tick = FALSE)
axis(side=1, at =ticks[a_even], labels=b[a_even],line = 2,tick = FALSE)

在不同级别绘制刻度线

Plot with ticks at different levels

plot

r

labels