Altair: Tooltips not showing up in chart

[afonit]

I have been puzzling over this for awhile. I have developed a small reproducible example but I still have been unable to uncover the issue.

Here is the reproducible example:

data = {'week_ending': ['2020-03-22', '2020-03-08', '2020-03-15',
                       '2020-03-22', '2020-03-08', '2020-03-15',
                       '2020-03-22', '2020-03-08', '2020-03-15',
                       '2020-03-22', '2020-03-08', '2020-03-15',
                       '2020-03-22', '2020-03-08', '2020-03-15',
                       '2020-03-22', '2020-03-08', '2020-03-15',
                       '2020-03-22', '2020-03-08', '2020-03-15',
                       '2020-03-22', '2020-03-08', '2020-03-15'],
       'impact_event': ['a', 'b', 'c',
                       'b', 'c', 'a',
                       'c', 'a', 'b',
                       'a', 'b', 'c',
                       'b', 'c', 'a',
                       'c', 'a', 'b',
                       'a', 'b', 'c',
                       'a', 'b', 'c'],
       'impact_level': [1, 4, 9,
                       2, 7, 2,
                       3, 9, 4,
                       1, 7, 9,
                       2, 7, 2,
                       3, 2, 4,
                       1, 4, 9,
                       1, 4, 9,],
       'typeof': ['g1', 'g1', 'g1',
                 'g1', 'g1', 'g1',
                 'g1', 'g1', 'g1',
                 'g1', 'g1', 'g1',
                 'g1', 'g1', 'g1',
                 'g1', 'g1', 'g1',
                 'g1', 'g1', 'g1',
                 'g2', 'g2', 'g2',]}

df = pd.DataFrame(data)



df['agg_value'] = df.groupby(['week_ending', 'impact_event', 'typeof']).transform('sum')
df['cum_num'] = df.groupby(['week_ending', 'impact_event', 'typeof']).cumcount()

# Generate the Chart

selector = alt.selection_single(empty='none',
                                fields=['week_ending', 'impact_event', 'typeof'])
base_data = alt.Chart(df)

base = base_data.mark_rect(color='green', opacity=.2).encode(
    x='week_ending:O',
    y='impact_event:O'
).transform_filter('datum.cum_num==0')

textof = base_data.mark_text(color='white').encode(
    x='week_ending:O',
    y='impact_event:O',
    text='agg_value:Q')

detail_breakout = base_data.mark_circle(color='orange', size=250, opacity=.3).encode(
    x='impact_level:N',
    y='impact_level:N',
    tooltip=['impact_level', 'agg_value']).transform_filter(selector)

alt.vconcat(detail_breakout, alt.layer(base.add_selection(selector), textof).facet(row=alt.Row('typeof:O')))

To make sense of the data structure look at it this way:

df.sort_values(['week_ending', 'impact_event', 'typeof'])

Upon execution it looks like this:

Click on the top left cell (I have left out coloring rules to keep the example as simple as possible), where the value is 11 and the chart will look like this:

The issue is when I hover over the yellow circles, I am not getting the tool tips.

Generating that top chart on its own gives me the tool tips, but when it is all put together, I am not getting them.
For example:

base_data.mark_circle(color='orange', size=250, opacity=.3).encode(
    x='impact_level:N',
    y='impact_level:N',
    tooltip=['impact_level', 'agg_value'])

Produces:

[jakevdp]

Thanks for the report. This is a known vega-lite bug: https://github.com/vega/vega-lite/issues/6003

Here's a more concise reproduction of the issue:

import altair as alt
data = {'values': [{'x': 1}]}
chart = alt.Chart(data).mark_rect(tooltip=True).encode(x='x:O')
chart | chart.add_selection(alt.selection_single())

You can work around this by adding a dummy selection to the chart on which you want the tooltips to show up. In your example, you would add this line:

detail_breakout = detail_breakout.add_selection(alt.selection_single())

[SangHuynh24]

Thanks for the report. This is a known vega-lite bug: vega/vega-lite#6003

Here's a more concise reproduction of the issue:

import altair as alt
data = {'values': [{'x': 1}]}
chart = alt.Chart(data).mark_rect(tooltip=True).encode(x='x:O')
chart | chart.add_selection(alt.selection_single())

You can work around this by adding a dummy selection to the chart on which you want the tooltips to show up. In your example, you would add this line:

detail_breakout = detail_breakout.add_selection(alt.selection_single())

Thanks a lot! This is what I am searching for my same problem.