Altair: Using a symlog scale?

[mattpitkin]

Is there any way to use a symlog scale for axes in Altair. If not would it be possible/relatively simple to add this in the future?

[jakevdp]

I don't think this is supported in Vega-Lite. It might be worth doing a feature request there.

[mattpitkin]

@jakevdp - thanks. I'll do as you suggest and see if there's the possibility of adding this to Vega-Lite.

[willwhitney]

This appears to be supported now in Vega-Lite (see https://vega.github.io/vega-lite/docs/scale.html#symlog).

[jakevdp]

The current docs on the Vega-Lite website are for the version 3.0 pre-release. Once Vega-Lite 3 is released we will work to update altair to incorporate new features like this one.

[willwhitney]

Ah, got it. Sorry for the false alarm!
On Feb 28, 2019, 11:21 PM -0500, Jake Vanderplas [e-mail], wrote:

The current docs on the Vega-Lite website are for the version 3.0 pre-release. Once Vega-Lite 3 is released we will work to update altair to incorporate new features like this one.
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[mattpitkin]

Now that vega-lite v3 has been released has the symlog support been incorporated into Altair?

[jakevdp]

Yes, for example:

import altair as alt
import pandas as pd

df = pd.DataFrame({
    'x': range(-50, 50),
    'y': range(100),
})

alt.Chart(df).mark_line().encode(
    alt.X('x', scale=alt.Scale(type='symlog')),
    alt.Y('y')
)

[mattpitkin]

Excellent, thanks.