使用 ggplot2 如何在图例中表示点和线 [英] Using ggplot2 how can I represent a dot and a line in the legend

问题描述

使用 ggplot2 我正在绘制几个函数和一系列点.我不知道如何表示图例上的点.我意识到我需要使用 aes() 函数，但我不完全明白如何做到这一点.我很抱歉这个例子太长了，但我不知道如何说明它.

Using ggplot2 I am plotting several functions and a series of points. I cannot figure out how to represent the points on the legend. I realize I need to use an aes() function, but I don't fully understand how to do this. I apologize that the example is so long, but I don't know how else to illustrate it.

## add ggplot2
library(ggplot2)

# Declare Chart values
y_label = expression("y_axis"~~bgroup("(",val / km^{2},")"))
x_label = "x_axis"

#############################
## Define functions
# Create a list to hold the functions
funcs <- list()
funcs[]

# loop through to define functions
for(k in 1:21){

# Make function name
funcName <- paste('func', k, sep = '' )

# make function
func = paste('function(x){exp(', k, ') * exp(x*0.01)}', sep = '')

funcs[[funcName]] = eval(parse(text=func))

}

    # Specify values
    yval = c(1:20)                              
    xval = c(1:20)                                

    # make a dataframe
    d = data.frame(xval,yval)

    # Specify Range
    x_range <- range(1,51)

# make plot
p <-qplot(data = d,
        x=xval,y=yval,        
        xlab = x_label, 
        ylab = y_label,
        xlim = x_range
        )+ geom_point(colour="green")


for(j in 1:length(funcs)){

p <- p + stat_function(aes(y=0),fun = funcs[[j]], colour="blue", alpha=I(1/5))

}

# make one function red
p <- p + stat_function(fun = funcs[[i]], aes(color="red"), size = 1) +
    scale_colour_identity("", breaks=c("red", "green","blue"),
    labels=c("Fitted Values", "Measured values","All values")) 

# position legend and make remove frame
p <- p + opts(legend.position = c(0.85,0.7), legend.background = theme_rect(col = 0)) 

print(p)     

预先感谢您 - 在过去的几天里，我从这个社区学到了很多东西.

Thank you in advance - I have learned I a lot from this community over the last few days.

推荐答案

请参阅下面的解决方案.主要思想如下:想象点下面有一条不可见的线，线有不可见的点.因此，每个系列"都会获得颜色、形状和线型属性，最后我们将根据需要手动将它们设置为不可见值(0 表示线，NA 表示点).ggplot2 会自动合并三个属性的图例.

See below for a solution. The main idea is the following: imagine the points having an invisible line under them, and the lines having invisible points. So each "series" gets color and shape and linetype attributes, and at the end we will manually set them to invisible values (0 for lines, NA for points) as necessary. ggplot2 will merge the legends for the three attributes automatically.

# make plot 
p <- qplot(data = d, x=xval, y=yval, colour="Measured", shape="Measured",
          linetype="Measured",  xlab = x_label,   ylab = y_label, xlim = x_range,
          geom="point") 

#add lines for functions 
for(j in 1:length(funcs)){ 
   p <- p + stat_function(aes(colour="All", shape="All", linetype="All"), 
                          fun = funcs[[j]],  alpha=I(1/5), geom="line")  
} 

# make one function special 
p <- p + stat_function(fun = funcs[[1]], aes(colour="Fitted", shape="Fitted",
                       linetype="Fitted"), size = 1, geom="line")

# modify look 
 p <- p +  scale_colour_manual("", values=c("green", "blue", "red")) + 
           scale_shape_manual("", values=c(19,NA,NA)) + 
           scale_linetype_manual("", values=c(0,1,1)) 

print(p) 

这篇关于使用 ggplot2 如何在图例中表示点和线的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！