ggplot中的手动颜色映射

Question

我想用同一组图例绘制几个不同的数据集，但并非所有数据集都具有所有图例标签，因此我只想为所有图例绘制一个图例，并为每个图例标签使用相同的颜色。

我的数据看起来像这样

Sample  Activity    Location    Value
brain   A1  -99 0.000480219165072995
brain   A1  -98 0.000310998665750027
brain   A1  -97 0.00013269798404962
brain   A1  -96 0.000414032362112828
brain   A1  -95 0.000484106264682014
brain   A1  -94 0.000277469810522874
brain   A1  -93 -0.000312328089983588
brain   A1  -92 -0.000326948367221977
brain   A1  -91 -0.000566097491837788
brain   A2  -99 0.023199362386866
brain   A2  -98 0.0232008290610013
brain   A2  -97 0.0235067519290527
brain   A2  -96 0.0235475873183088
brain   A2  -95 0.0237440466425034
brain   A2  -94 0.0240249966894288
brain   A2  -93 0.0245502842927103
brain   A2  -92 0.0244587160446747
brain   A2  -91 0.0252699000904297

所以我想为 Activity 绘制两条线，一种颜色用于 A1，另一种颜色用于 A2 等。

大约有 8 种不同的活动和许多地点。

如何为每个 Activity 手动设置颜色？例如，A1 永远是红色的，A2 永远是黑色的，A3 永远是蓝色的等等......？

ggplot(data=df,aes(x=Location,y=Value,group=Activity))+geom_line(aes(colour=Activity),size=1.5)+theme_bw()

Answer 1

只需遵循@MrFlick's comment 中的建议（代码如下）

df <- structure(list(Sample = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "brain", class = "factor"), 
    Activity = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
    2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L), .Label = c("A1", "A2"
    ), class = "factor"), Location = c(-99L, -98L, -97L, -96L, 
    -95L, -94L, -93L, -92L, -91L, -99L, -98L, -97L, -96L, -95L, 
    -94L, -93L, -92L, -91L), Value = c(0.000480219165072995, 
    0.000310998665750027, 0.00013269798404962, 0.000414032362112828, 
    0.000484106264682014, 0.000277469810522874, -0.000312328089983588, 
    -0.000326948367221977, -0.000566097491837788, 0.023199362386866, 
    0.0232008290610013, 0.0235067519290527, 0.0235475873183088, 
    0.0237440466425034, 0.0240249966894288, 0.0245502842927103, 
    0.0244587160446747, 0.0252699000904297)), .Names = c("Sample", 
"Activity", "Location", "Value"), class = "data.frame", row.names = c(NA, 
-18L))


# install.packages("ggplot2", dependencies = TRUE)
library(ggplot2)

p <- ggplot(data=df,aes(x=Location,y=Value,group=Activity))+geom_line(aes(colour=Activity),size=1.5)+theme_bw()
p + scale_color_manual(values=c("red", "blue")) # add more …