Add symlog scale

[mattpitkin]

Sometimes you have data that spans a many orders of magnitude across both positive and negative values. It is often useful to be able to plot both the positive and negative ranges on a logarithmic scale, with a linear range spanning between them. This is done in, e.g., Matplotlib, using the symlog scaling.

Would adding something like this be possible in Vega-Lite?

Refs vega/altair#1077.

[domoritz]

Thanks for the issue. Before we can add this to Vega-Lite, we need support for this in Vega. Can you file an issue there and link to this one?

[mattpitkin]

@domoritz - thank. Yes, I'll file issue in the Vega repo.

[domoritz]

Closing this until we get support in D3 and Vega.

[mattpitkin]

@jheer once vega/vega#1544 appears in the next Vega release, will it be possible/simple to also add symlog support into vega-lite?

[domoritz]

Yes, we will add it to Vega-Lite 3.

[domoritz]

You're very welcome to send a PR to update Vega-Lite to the new scales as well.

[mattpitkin]

Thanks

[mattpitkin]

I'll take a look and see if it's reasonably obvious how to add it. I assume it would be along the lines of adding it as another continuous scale option in https://github.com/vega/vega-lite/blob/master/src/scale.ts?

…

On Sat, 16 Feb 2019, 20:47 Dominik Moritz, ***@***.***> wrote: You're very welcome to send a PR to update Vega-Lite to the new scales as well. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#4127 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABWvJKZaR1FZXUDdvX03Mm-dRyyfgJdBks5vOG5lgaJpZM4V3zJI> .

[domoritz]

It might be a bit more involved since Vega's scales are different now. It's not just about adding a new scale type but updating the existing onces as well.