It is a given that Viz In Tooltip is a pretty amazing Tableau feature; however what if I were to tell you a visualisation could have two different Viz In Tooltip applied to the same data point?! No, not black magic, just a cool way of utilising a dual axis to apply different Viz In Tooltip sheets to each of the 2 axis.
How it could be useful
Imagine you had a line chart analysing monthly data; the dual axis technique could be used to allow you to hover over the line of the dual axis to view the data for a given month but now at a daily granularity, whilst viewing the monthly data split by dimension when you hover over the circle of the dual axis.
How to create two Viz In Tooltip
Utilising this technique is actually pretty simple:
1. Create a dual axis line chart and synchronise axis
2. Change the 2nd marks card to be a circle to ensure your can easily distinguish between the 2 elements being visualised
3. Create 2 additional worksheets; 1 line chart visualising the same data but at a daily granularity and 1 bar chart visualising a chosen dimension rather than your time series dimension
4. Add the additional line chart as the Viz In Tooltip for your 1st Marks card and add the additional bar chart as the Viz In Tooltip for your 2nd Marks card; ensuring you set <All fields> as the Viz In Tooltip filter
You will now be able to hover over a month in the visualisation and see the daily analysis of events when hovering over the line and see the team analysis of events when hovering over the dot.
Of course this same technique could be applied to any combination of dual axis chart, you do not necessarily have to select a line and circle as your two Marks Card visualisations.