Code for Ticks Control with Vegalite.jl

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1

I tried before, searched the Vegalite.jl documentation, searched the original Vegalite documentation (and tried to convert some code), considered somewhat directly using JSON-like code, and didn’t succeed in this matter. I left it alone for a while because it wasn’t so important at the time.

Now it has become important: what is the most direct and easy code example to control ticks with Vegalite.jl?

(Can you also use a range with steps to signify ticks?)
(Is there any plan to expand the existing Vegalite.jl documentation, or even fully translate the original Vegalite documentation?)

2

Here is an example on how to change some tick aspects:

cars |>
@vlplot(
  :point,
  x={:Miles_per_Gallon, axis={tickSize=50, tickWidth=3, values=[5, 7,34]}},
  y=:Displacement
)

You can get the documentation for the other options here. Let me know if that helps you get started!

I think you should be able to use a julia range as the value for values.

Any help with expanding the documentation would be super welcome. I don’t think I’ll have much time to spend on that in the near future. I also thought whether there might be some way to auto-translate the original documentation and incorporate that into the Julia docs, but never really had enough time to explore that option. I think Altair (the python wrapper for vega-lite) does that, but not sure.

1 Like
3

Thanks. It certainly helps me get going.

There still seems to be a problem, as I cannot enforce e.g. the X axis ticks beyond the automatically detected visual reach of data. For example, SepalLength in the iris set goes up to 8, but I cannot set the X ticks to reach 10. (I used values = collect(2:10), or just 2:10, which does start the X ticks at 2, but also leaves a big blank space to the left between 2 and the undesired 0.)

The range way with a step also does not work, and totally removes the ticks (in this case on the Y axis).

I think I am not qualified to help you at the moment. I still need to get better at Vegalite.jl.

4

If you want to change the range of values shown you need to adjust the scale:

cars |> @vlplot(
  :point,
  x={
    :Miles_per_Gallon,
    axis={tickSize=50, tickWidth=3, values=2:10:30},
    scale={domain=[0, 100]}
  },
  y=:Displacement
)

Can you post the code you are using? The range syntax I’m using in the above example seems to work on my system.

5

This time I took your last example code (and changing ticksize to 5 and tickWidth to 1).

If I use for values a simple array like [0, 40, 80, 100], it works as expected, and these specific values are shown.

If I use a range, like 0:10:100, the X axis shows no ticks at all.

6

Strange, this code:

cars |> @vlplot(:point, x={:Miles_per_Gallon, axis={values=2:10:100}, scale={domain=[0, 100]}}, y=:Displacement, width=600, background=:white)

produces this plot for me:
foo

which does pick up the range for the axis values… Can you post the exact code you are using?

7

Thanks for the help.

Yes. I will post it probably today or tomorrow. (Just writing this to let you know I haven’t forgotten you or your request.)

1 Like
8

Here is the code I used this time:

cars |>
  @vlplot(
    :point,
    x = {
      :Displacement,
      scale = {
        domain = [0, 600]
      },
      axis = {
        tickSize = 5,
        tickWidth = 1,
        values = [0:50:600]
      }
    },
    y = {
      :Miles_per_Gallon,
      title = "MPG"
    },
    width = 300,
    height = 300
  )
9

Try to use values = 0:50:600 instead of values = [0:50:600].

The expression [0:50:600] creates an array of ranges, which is not what you want to pass here (you can also think of that as an array of arrays). The expression 0:50:600 creates just a range, and any range is a subtype of AbstractArray, so you are passing an array of ticks in that case.

With that change the plot looks good on my system.

1 Like
10

Ohhh, why didn’t I see that?!