So far, we have used the default styling for our box plots. In this recipe, we will learn how to change the colors, widths, and styles of various elements of a box plot.
We will continue using the base graphics library functions, so we need not load any additional library or package. We just need to run the recipe code at the R prompt. We can also save the code as a script to use it later. Here, we will use the metals.csv
example dataset again:
metals<-read.csv("metals.csv")
We can build a box plot with custom colors, widths, and styles in the following way:
boxplot(metals[,-1], border = "white",col = "black",boxwex = 0.3, medlwd=1, whiskcol="black",staplecol="black", outcol="red",cex=0.3,outpch=19, main="Summary of metal concentrations by Site") grid(nx=NA,ny=NULL,col="gray",lty="dashed")
We have used a few different arguments in the example to change the styling of the box plot. The first two are col
and border
, which set the box color and border color, respectively. Note that the border
argument also sets the color for the median line, unless it is specified using the medcol
argument.
In the example, in addition to using boxwex
to adjust box widths, we used medlwd
to set the width of the median line. We set the color of the whiskers and staple using whiskcol
and staplecol
, respectively. The color and symbol type of the outlier points were set using outcol
and outpch
, respectively. The size of the points was set using the cex
argument.
We can set the color, size, and styling for each of the components. If you type in ?bxp
at the R prompt, you can see the help section for the bxp()
function, which is called by boxplot()
to do the actual drawing. The following table gives a summary:
Argument to boxplot() |
Corresponding setting |
---|---|
|
Box outline type, width, color, and fill color |
|
Median line type, line width, point character, point size expansion, color, and background color |
|
Whisker line type, width, and color |
|
Staple line type, width, line width expansion, and color |
|
Outlier line type, line width, line width expansion, point character, point size expansion, color, and background color |
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