46

我正在绘制在来自两个群体的每个个体中测量的两种同位素的相关系数（值 = 0.0:1.0）。我想为我的散点图设置一个固定的纵横比，这样无论图形设备如何，x 轴和 y 轴的大小都完全相同。建议？

这是我在 R 中的第一个情节，对我的代码的改进有任何评论吗？最后，是否值得投资学习基本的绘图技术，还是应该直接跳到 ggplot2 或 lattice？

我的剧情脚本：

## Create dataset
WW_corr <-
structure(list(South_N15 = c(0.7976495, 0.1796725, 0.5338347,
0.4103769, 0.7447027, 0.5080296, 0.7566544, 0.7432026, 0.8927161
), South_C13 = c(0.76706752, 0.02320767, 0.88429902, 0.36648357,
0.73840937, 0.0523504, 0.52145159, 0.50707858, 0.51874445), North_N15 = c(0.7483608,
0.4294148, 0.9283554, 0.8831571, 0.5056481, 0.1945943, 0.8492716,
0.5759033, 0.7483608), North_C13 = c(0.08114805, 0.47268136,
0.94975596, 0.06023815, 0.33652839, 0.53055943, 0.30228833, 0.8864435,
0.08114805)), .Names = c("South_N15", "South_C13", "North_N15",
"North_C13"), row.names = c(NA, -9L), class = "data.frame")

opar <- par()

## Plot results
par(oma = c(1, 0, 0, 0), mar = c(4, 5, 2, 2))           
plot(1,1,xlim=c(0:1.0), ylim=c(0:1.0), type="n", las=1, bty="n", main = NULL,
     ylab=expression(paste("Correlation Coefficient (r) for ", delta ^{15},"N ",
                     "\u0028","\u2030","\u0029")),
     xlab=expression(paste("Correlation Coefficient (r) for ", delta ^{13},"C ",
                     "\u0028","\u2030","\u0029")))

points(WW_corr$South_N15, WW_corr$South_C13, pch = 23, cex = 1.25, 
       bg ="antiquewhite4", col = "antiquewhite4")
points(WW_corr$North_N15, WW_corr$North_C13, pch = 15, cex = 1.25,
       bg ="black")
axis(1, at = seq(0, 1.0, by = 0.1), labels = F, tick = TRUE, tck = -0.01)
axis(2, at = seq(0, 1.0, by = 0.1), labels = F, tick = TRUE, tck = -0.01)
abline(h=.86, v=.86, col = "gray60", lty = 2)
legend("topleft", c("North", "South"), pch = c(15, 23), 
       col = c("black", "antiquewhite4"), pt.bg = c("black", "antiquewhite4"),
       horiz=TRUE, bty = "n")

par(opar)
4

2 回答 2

53 
par(pty="s")
plot(...)

sets the plot type to be square, which will do the job (I think) in your case because your x and y ranges are the same. Fairly well hidden option documented in ?par.

于 2012-01-06T18:46:27.730 回答
49

用作 plot 的参数将 asp=1被低级 plot.window 调用解释，并且应该给你一个单一的纵横比。使用 ylim 和 xlim 的调用可能会与纵横比规范发生冲突，并且asp应该“占上风”。这是一个非常令人印象深刻的第一个 R 图，顺便说一句。和一个优秀的问题结构。高分。

一个不和谐的注意事项是你对结构的使用xlim=c(0:1.0)。因为 xlim 需要一个二元向量，所以我会预期 xlim=c(0,1)。如果您更改为不同的限制集，则击键次数更少，将来出错的可能性也更少，因为如果您尝试使用“0：2.5”，“：”运算符会给您带来意想不到的结果。

于 2012-01-01T15:08:08.703 回答