How do I anchor one side of axis limits?

Question

I have a data frame of positive x and y values that I want to present as a scatterplot in ggplot2. The values are clustered away from the point (0,0), but I want to include the x=0 and y=0 lines in the plot to show overall magnitude. How can I do this?

set.seed(349)
d <- data.frame(x = runif(10, 1, 2), y = runif(10, 1, 2))
ggplot(d, aes(x,y)) + geom_point()

Plot without (0,0)

But what I want is something roughly equivalent to this, without having to specify both ends of the limits:

ggplot(d, aes(x=x, y=y)) + geom_point() + 
  scale_x_continuous(limits = c(0,2)) + scale_y_continuous(limits = c(0,2))

Plot with (0,0)

I know this is an old question but I just ran into it question and there seems to be a better solution. Use the function `expand_limits(...)` specifying the limits you want to include. (probably a new addition which wasn't available a few years back) — Adi Sarid, Feb 26 '18 at 22:18

score 9 · Accepted Answer · answered Jul 24 '14 at 20:15

9

One option is to just anchor the x and y min, but leave the max unspecified

ggplot(d, aes(x,y)) + geom_point() +
  scale_x_continuous(limits = c(0,NA)) + 
  scale_y_continuous(limits = c(0,NA))

answered Jul 24 '14 at 20:15

MrFlick

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Ah, relevant documentation is in `ggplot2::xlim`: "If a `NA` value is substituted for one of the limits that limit is automatically calculated." – Blue Magister Jul 24 '14 at 20:19
1

I've got `Error in if (zero_range(range)) { : missing value where TRUE/FALSE needed` while trying this – David Arenburg Jul 24 '14 at 20:22
@DavidArenburg I just tried again in a clean R session and it worked fine. Tested using `ggplot2_1.0.0` with the sample data above. – MrFlick Jul 24 '14 at 20:24
Interesting, it was probably added on the last version – David Arenburg Jul 24 '14 at 20:28

score 1 · Answer 2 · answered Feb 16 '16 at 15:24

This solution is a bit hacky, but it works for standard plot also.

Where d is the original dataframe we add two "fake" data points:

d2 = rbind(d,c(0,NA),c(NA,0))

This first extra data point has x-coordinate=0 and y-coordinate=NA. This means 0 will be included in the xlim, but the point will not be displayed (because it has no y-coordinate).

The other data point does the same for the y limits.

Just plot d2 instead of d and it will work as desired.

If using ggplot, as opposed to plot, you will get a warning about missing values. This can be suppressed by replacing geom_point() with geom_point(na.rm=T)

One downside with this solution (especially for plot) is that an extra value must be added for any other 'per-data-point' parameters, such as col= if you give each point a different colour.

score 1 · Answer 3 · answered Feb 26 '18 at 22:20

1

Use the function expand_limits(x=0,y=0), i.e.:

set.seed(349)
d <- data.frame(x = runif(10, 1, 2), y = runif(10, 1, 2))
ggplot(d, aes(x,y)) + geom_point() + expand_limits(x = 0, y = 0)

answered Feb 26 '18 at 22:20

Adi Sarid

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How do I anchor one side of axis limits?

3 Answers3