How do I draw gridlines using abline() that are behind the data?

Question

When I draw grid lines on a plot using abline() the grid lines are drawn over the data.

Is there a way to draw the abline() lines behind the data? I feel this would look better.

Example:

x <- seq(0, 10)
y <- x
plot(x, y, col = 'red', type = 'o', lwd = 3, pch = 15)
abline(h = seq(0, 10, .5), col = 'lightgray', lty = 3)
abline(v = seq(0, 10, .5), col = 'lightgray', lty = 3)

The plot produced has the gray grid lines going over the data (red line). I would like the red line to be on top of the gray lines.

score 47 · Accepted Answer · edited Sep 01 '11 at 21:27

47

The panel.first argument of plot() can take a list or vector of functions so you can put your abline() calls in there.

plot(1:4, panel.first = 
       c(abline(h = 1:4, lty = 2, col = 'grey') 
        ,abline(v = 1:4, lty = 2, col = 'grey')))

edited Sep 01 '11 at 21:27

Gavin Simpson

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answered Aug 31 '11 at 22:05

John

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I appreciate this answer. I already tell I'm going to be using panel.first a lot in the future. – maxwelljd Sep 13 '11 at 16:50
how to do the same for boxplot? – Jaleks Oct 31 '21 at 09:44
This should be a new question, not a comment. But see methods below since boxplot doesn't rely on plot. – John Nov 01 '21 at 11:30

score 16 · Answer 2 · answered Aug 31 '11 at 21:45

Use plot() to set up the plotting window, but use type = "n" to not plot any data. Then do your abline() calls, or use grid(), and then plot the data using whatever low-level function is appropriate (here points() is fine).

x <- seq(0, 10)
y <- x
plot(x, y, type = "n")
abline(h = seq(0, 10, .5), col = 'lightgray', lty = 3)
abline(v = seq(0, 10, .5), col = 'lightgray', lty = 3)
points(x, y, col = 'red', type = 'o', lwd = 3, pch = 15)

or

## using `grid()`
plot(x, y, type = "n")
grid()
points(x, y, col = 'red', type = 'o', lwd = 3, pch = 15)

See ?grid for details of how to specify the grid as per your abline() version.

score 8 · Answer 3 · answered Aug 31 '11 at 21:45

8

Plot first with type="n" to establish coordinates. Then put in the grid lines, then plot again with your regular plot type:

plot(x, y, col = 'red', type = 'n', lwd = 3, pch = 15)
abline(h = seq(0, 10, .5), col = 'lightgray', lty = 3)
abline(v = seq(0, 10, .5), col = 'lightgray', lty = 3)
par(new=TRUE)
plot(x, y, col = 'red', type = 'o', lwd = 3, pch = 15)

I admit that I have always thought the name for that par parameter was "backwards."

answered Aug 31 '11 at 21:45

IRTFM

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backwards, and not really needed if you plot the data using `points()` for example. – Gavin Simpson Aug 31 '11 at 21:46
I didn't realize that 'type' argument was available in `points`. – IRTFM Aug 31 '11 at 21:50
It's not necessary with points(). I think Gavin was implying that you would make your initial type = 'n' plot() call as you did but then just change your last line to points( instead of plot(. Then the par() call isn't needed. BTW, type is available in points and lines I believe, I know that I sometimes want both and just call lines() with type = 'b'. – John Aug 31 '11 at 22:15
I understood his point. I was just explaining why I didn't use two calls to points and lines. – IRTFM Aug 31 '11 at 22:41

score 1 · Answer 4 · answered Sep 01 '11 at 16:31

1

Another way of creating grid lines is to set tck=1 when plotting or in the axis function (you may still want to plot the points using points after creating the grid lines.

answered Sep 01 '11 at 16:31

Greg Snow

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How do I draw gridlines using abline() that are behind the data?

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