将 R 条形图转换为绘制 2 条线并添加数据点

Question

我需要绘制一个 2 线 R 程序图，其中一条数据点位于一条线上，并且最小 Y 值设置为 -6。以下数据为.csv输入文件：

> cat verifyRecording.csv
Time,MaxDBK,DBChange
07:30,20,2
07:35,21,1
07:40,22,0
07:45,23,-1
07:50,24,-2
07:55,32,-5
08:00,19,3

下面是一个 R 程序，它接受上面的 .csv 输入并输出一个有 2 行的条形图。我只需要 2 条线，因此它需要将条形图转换为 2 线（绘图）图表。然后在 DBChange 线上添加 d1$DBChange 数据点，并将最小 Y 值设置为 -6。

#!/usr/bin/Rscript
d1 <- read.csv(file="verifyRecording.csv",head=T,sep=",")

# Provide an image size which will ensure the x labels display
png(filename="verifyRecording.png", width=1024, bg="white")

# Replace the barplot function with a plot function.
# Fix the Y values be to actually show -6 as the minimum value.
mp <- barplot(d1$MaxDBK, ylim=c(-6,50), main="Sound Recording started: 05/21/2017 7:25 AM", xlab="Time in 24hr", ylab="Sound in Decibals", border='blue')
axis(1,at=mp,labels=d1$Time)

lines(mp,d1$DBChange,type="o",pch=19,lwd=2,col="red")
lines(mp,d1$MaxDBK,type="o",pch=19,lwd=2,col="blue")

#  Display the DBChange data values on the d1$DBChange line points.
#####  points(d1$Time, d1$DBChange, type="l", col="red")

legend("topright", c("Recommended_DB_Change","Max_DB_Volume"), lty=c(1,1), lwd=c(2.5,2.5), col=c("red","blue"))

dev.off() 

Answer 1

如果您以空图而不是条形图开始，则可以仅使用线条来绘制图。这样，您只需在其中添加您想要的元素。

# Empty plot ("type = "n")
# xaxt = "n" in place to allow labelling with axis
# Set y axis limits
plot(1:nrow(d1), d1$MaxDBK, type = "n", ylim = c(-6, 50), xaxt = "n",
         main = "Sound Recording started: 05/21/2017 7:25 AM", 
         xlab = "Time in 24hr", 
         ylab = "Sound in Decibals")

# Lines added
    lines(d1$Time, d1$MaxDBK,type = "o",   pch = 19, lwd = 2, col = "blue")
    lines(d1$Time, d1$DBChange,type = "o", pch = 19, lwd = 2, col = "red")

# Label added in x axis. Changed at value to show properly    
    axis(side = 1, labels = d1$Time, at = d1$Time)

# Label each point with the values in d1$DBChange
    text(d1$Time, d1$DBChange, labels = d1$DBChange, pos = 3)