r - ggplot 中超过六种形状

Question

我想使用离散颜色绘制具有六组以上数据的不同形状的线条。问题是 1) 为线条颜色和形状生成了不同的图例，但应该只有一个具有线条颜色和形状的图例，2) 更正线条颜色图例的标题时，颜色消失。

t=seq(0,360,20)
for (ip in seq(0,10)) {
  if (ip==0) {
    df<-data.frame(t=t,y=sin(t*pi/180)+ip/2,sn=ip+100)
  } else {
    tdf<-data.frame(t=t,y=sin(t*pi/180)+ip/2,sn=ip+100)
    df<-rbind(df,tdf)

  }
}
head(df)

# No plot
# Error: A continuous variable can not be mapped to shape
gp <- ggplot(df,aes(x=t,y=y,group=sn,color=sn,shape=sn))
gp <- gp + labs(title = "Demo more than 6 shapes", x="Theat (deg)", y="Magnitude")
gp <- gp + geom_line() + geom_point()
print(gp)

# No plot
# Error: A continuous variable can not be mapped to shape (doesn't like integers)
gp <- ggplot(df,aes(x=t,y=y,group=sn,color=sn,shape=as.integer(sn)))
gp <- gp + labs(title = "Demo more than 6 shapes", x="Theat (deg)", y="Magnitude")
gp <- gp + geom_line() + geom_point()
print(gp)

# Gives warning about 6 shapes, and only shows 6 shapes, continous sn colors
gp <- ggplot(df,aes(x=t,y=y,group=sn,color=sn,shape=as.factor(sn)))
gp <- gp + labs(title = "Only shows six shapes, and two legends, need discrete colors", 
                x="Theat (deg)", y="Magnitude")
gp <- gp + geom_line() + geom_point()
print(gp)

# This is close to what is desired, but correct legend title and combine legends
gp <- ggplot(df,aes(x=t,y=y,group=sn,color=as.factor(sn),shape=as.factor(sn %% 6)))
gp <- gp + labs(title = "Need to combine legends and correct legend title", x="Theat (deg)", y="Magnitude")
gp <- gp + geom_line() + geom_point()
print(gp)

# Correct legend title, but now the line color disappears
gp <- ggplot(df,aes(x=t,y=y,group=sn,color=as.factor(sn),shape=as.factor(sn %% 6)))
gp <- gp + labs(title = "Color disappeard, but legend title changed", x="Theat (deg)", y="Magnitude")
gp <- gp + geom_line() + geom_point()
gp <- gp + scale_color_manual("SN",values=as.factor(df$sn)) 
print(gp)

# Add color and shape in geom_line / geom_point commands, 
gp <- ggplot(df,aes(x=t,y=y,group=sn))
gp <- gp + labs(title = "This is close, but legend symbols are wrong", x="Theat (deg)", y="Magnitude")
gp <- gp + geom_line(aes(color=as.factor(df$sn))) 
gp <- gp + geom_point(color=as.factor(df$sn),shape=as.factor(df$sn %% 6))
gp <- gp + scale_color_manual("SN",values=as.factor(df$sn)) 
print(gp)

Answer 1

首先，将 sn 转换为因子会更容易。

df$sn <- factor(df$sn)

然后，您需要使用 scale_shape_manual 来指定要使用的形状。

gp <- ggplot(df,aes(x=t, y=y, group=sn,color=sn, shape=sn)) +
             scale_shape_manual(values=1:nlevels(df$sn)) +
             labs(title = "Demo more than 6 shapes", x="Theat (deg)", y="Magnitude") +
             geom_line() + 
             geom_point(size=3)
gp

这应该会给你你想要的。您需要使用 scale_shape_manual，因为即使使用 sn 作为因子，ggplot 也只会自动添加最多 6 个不同的符号。之后您必须手动指定它们。您可以通过多种方式更改符号。请查看这些页面以获取有关如何操作的更多信息:http://sape.inf.usi.ch/quick-reference/ggplot2/shape
http://www.cookbook-r.com/Graphs/Shapes_and_line_types/