一种方法是设置绘图纵横比,使用asp
参数,然后使用指定的角度计算角度asp
:
asp <- 2
plot(1:10,1:10, asp=asp)
abline(a=8, b=-1)
text(x=4, y=5, "reference line label", srt=180/pi*atan(-1*asp))
abline(a=4, b=-2)
text(x=1, y=3, "reference line label", srt=180/pi*atan(-2*asp))
设置不同的asp
:
asp <- 0.8
plot(1:10,1:10, asp=asp)
abline(a=8, b=-1)
text(x=4, y=5, "reference line label", srt=180/pi*atan(-1*asp))
abline(a=4, b=-2)
text(x=1, y=3, "reference line label", srt=180/pi*atan(-2*asp))