Q: Is it possible to modify the strokeWidth of a Strip Plot?

Here’s another question from my newsroom colleagues. One of them was pleased to make a strip chart this morning, but was frustrated by how small and faint the lines were. I thought that perhaps the strokeWidth option could fatten them up, but it didn’t seem to work.

Is there a way to do it? Here’s a rough example with some dummy data I’ve been playing with.

import pandas as pd
import altair as alt
from datetime import datetime
from vega_datasets import data

source = data.la_riots()
source = source[source.death_date < datetime(1993, 1, 1)]

alt.Chart(source).mark_tick(strokeWidth=50).encode(
    x='death_date:T'
)

[jakevdp]

In Altair 3, thickness is supported:

import pandas as pd
import altair as alt
from datetime import datetime
from vega_datasets import data

source = data.la_riots()
source = source[source.death_date < datetime(1993, 1, 1)]

alt.Chart(source).mark_tick(thickness=4).encode(
    x='death_date:T'
)

[kanitw]

Tick is drawn using a rectangle, so strokeWidth won’t work. In the pending VL 2.5, you can use thickness to customize this. (There was a bug that this thickness is missing.)

For now you can customize the thickness via the tick config.