geom_vline should work with non-numeric scales

[hadley]

e.g. date and character

[HarlanH]

Here here!

For dates, the workaround is to wrap the Date with as.numeric, ala: geom_vline(xintercept=as.numeric(Sys.Date))

[hadley]

@HarlanH would you mind contributing a couple of reproducible examples?

[BrianDiggs]

DF <- data.frame(dt = as.Date("2000-01-01")+0:20, val=0:20)

ggplot(DF, aes(x=dt, y=val)) +
  geom_point() +
  geom_vline(xintercept=as.Date("2000-01-10"))

ggplot(DF, aes(x=dt, y=val)) +
  geom_point() +
  geom_vline(xintercept=as.numeric(as.Date("2000-01-10")))

The first does not have a vertical line; the second does, at the expected location. This was run with 0.8.9. This is not up to a testable example, but it is a start.

If you are going to handle non-numeric scales, then this should work as well

ggplot(iris, aes(x=Species, y=Sepal.Length)) +
  geom_point() +
  geom_vline(xintercept="setosa")

[davidcoallier]

I know this issue is more than 2 years old but I figured I'd add a comment.

When using the following code (DF from above in this case):

ggplot(DF, aes(x=dt, y=val)) +
    geom_point() +
    geom_vline(
        xintercept = as.numeric(as.Date("2001-01-10")))

One has to be careful that the values used for the x-axis date-values are formatted using the same standard.

For instance, if your data-frame DF contains dates formatted using as.POSIXct instead of as.Date your plot will look quite weird. e.g.:

DF <- data.frame(dt = as.POSIXct("2000-01-01")+0:20, val=0:20)

ggplot(DF, aes(x=dt, y=val)) +
  geom_point() +
  geom_vline(xintercept=as.Date("2000-01-10"))

ggplot(DF, aes(x=dt, y=val)) +
  geom_point() +
  geom_vline(xintercept=as.numeric(as.Date("2000-01-10")))

For instance, the as.numeric values for the date "2000-01-10" is the following:

• as.POSIXct("2000-01-10"): 979084800
• as.Date("2000-01-10"): 11332

This example is trivial since we know that DF has been defined with as.Date but I've encountered larger codebases where the likes of :

format(as.POSIXct("2001-01-10"), format="%Y-%m-%d")

made it a lot more annoying to process when generating plots.

It is a really simple tip however if you are running larger sequential list of intercepts and your dataset is large, your memory will burst in tears straight through the roof.

[hadley]

This sounds like a great feature, but unfortunately we don't currently have the development bandwidth to support it. If you'd like to submit a pull request that implements this feature, please follow the instructions in the development vignette.