我正在尝试在ggplot2中绘制拟合模型效果，以替代effects包返回的图，并且在将连续分组因子映射到{{ 1}}。这些问题源于分组因子具有偏斜分布的事实。使用默认的颜色映射，大多数颜色是无法区分的，但是对数转换会混淆图例。我查看了一些不太适合的相关SO答案（Is there a built-in way to do a logarithmic color scale in ggplot2?，R colour scale for logarithmic data?和Logarithmic color scale in ggplot2 squishes certain legend numbers）。
这是我的数据：
scale_color_gradient在这里，分组因子myEffs <- structure(list(PrimeShiftIndex = c(-4, -0.2, 4, -4, -0.2, 4,
-4, -0.2, 4, -4, -0.2, 4), PrimeVowelDur = c(0.03, 0.03, 0.03,
0.06, 0.06, 0.06, 0.09, 0.09, 0.09, 1.59, 1.59, 1.59), fit = c(-0.184306629528313,
-0.164313919815862, -0.142216714344205, -0.200749305969527, -0.178039844592615,
-0.152939913597082, -0.210367655099129, -0.186068995874736, -0.159212583047775,
-0.278488972243709, -0.242934925102426, -0.203638346683111),
se = c(0.0437103286485701, 0.0342751848548937, 0.0446524040373885,
0.0417352317881704, 0.0340007746839495, 0.042093900962637,
0.0441609220226782, 0.0341565687974652, 0.0442166991273061,
0.0995662189943997, 0.041203801253227, 0.0993299532144987
), lower = c(-0.269979086288845, -0.231493448847753, -0.229735643449126,
-0.282550563276701, -0.24468152835471, -0.235444164230796,
-0.296923277064622, -0.253016036857112, -0.245877528409642,
-0.473639245768052, -0.323694575976204, -0.398325538129639
), upper = c(-0.0986341727677806, -0.0971343907839703, -0.0546977852392849,
-0.118948048662354, -0.11139816083052, -0.0704356629633676,
-0.123812033133635, -0.119121954892359, -0.0725476376859078,
-0.0833386987193667, -0.162175274228647, -0.00895115523658357
)), class = "data.frame", row.names = c(NA, -12L), .Names = c("PrimeShiftIndex",
"PrimeVowelDur", "fit", "se", "lower", "upper"))
向右偏，其值为PrimeVowelDur，0.03，0.06和0.09。这是获得可区分的颜色和可读图例的一些失败尝试（用令人讨厌的粗线突出显示颜色对比或缺乏对比）。
1.59我的直觉是p <- ggplot(myEffs, aes(x=PrimeShiftIndex, y=fit, group=PrimeVowelDur, color=PrimeVowelDur)) +
geom_line(size=6)
##Legend fine but line colors indistinguishable
p
##Missuse's suggestion yields the same issue
p + scale_color_gradientn(colors = colorRampPalette(colors = c("#132B43", "#56B1F7"))(nrow(myEffs)),
values = scales::rescale(log(sort(myEffs$PrimeVowelDur))))
##Colors distinguishable but legend messed up
p + scale_color_gradient(trans="log")
##Using trans="log" with pre-defined breaks as per Gregor doesn't make legend much better
brks <- seq(0, 1.6, length.out=5)
p + scale_color_gradient(trans="log", breaks=brks, labels=brks)
##Nor does S Rivero's suggestion
p + scale_color_gradient(trans="log", breaks=brks, labels=brks, guide="legend")
应该能够自然地处理ggplot解决方案而不会弄乱图例。无论如何，我有一个建议的解决方案，但是我想看看是否有任何我想念的东西。
答案 0 :(得分：1)
如果您基于连续分组因子的值将中断传递给breaks的{{1}}和labels参数，则图例将按预期显示。无论您使用默认的颜色栏指南还是图例指南，该方法均有效：
scale_color_gradient