CODEWITHSUNDEEP
rplotcolors
Shawn Janzen
Shawn Janzen

Reputation: 437

How to I resize the outline of a pch plot point in base R?

I'm tinkering with cex options in base R plots to resize my plot for a presentation slide. I seem to be able to tweak most size aspects, but I notice the outline color of my pch point is not getting any bolder/thicker when the plot point becomes larger. So the larger the plot point, the less noticeable the outline color.

Found many websites (& SO posts) on various cex options (cex, cex.main, cex.sub, cex.axis, cex.lab), but none seem to be adjusting the pch plot point.

I'm aware that only certain pch symbols (21 to 25) can be used with fill color and outline. My sample code uses 21 (circle).

data("mtcars")  # test data
summary(mtcars[c("hp","mpg")]) # to find on min & max values to set plot limits

# set general features used for multiple plots
par(bg="blue", fg="red", col="yellow", col.axis="white", col.lab="white", bty="n", cex=1.5)

# test plot to illustrate, cex used here to further adjust plot points from par setting
plot(mtcars$hp, mtcars$mpg, ylim=c(10, 35), xlim=c(50, 340), pch=21, bg="red", cex=2)

Am I missing something about cex or is there a different solution without turning to ggplot? I'm not adverse to ggplot if there is an option, but I'd like to see if it can be done in base R.

Upvotes: 2

Views: 2863

Answers (1)

d.b
d.b

Reputation: 32548

You need to specify lwd to change the border thickness of pch symbol

plot(1:10, 1:10, pch = 21, cex = 3, lwd = 1:10)

enter image description here

Upvotes: 5

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