1 Reply Latest reply on Sep 19, 2019 6:18 AM by Diego Parker

    Filtering by one dimension and showing history of another

    Stephanie Walton

      Hi there - I am working with two datasets: one that is a shapefile of every US congressional district for the past 30 years and one that is an XLS file of every mass shooting over the same period and their lat/long. I have combined them in Tableau using a full outer join using this method and have created a dual axis so that I get this map. (Apologies for using screenshots - I'm working in Tableau Public and am not able to upload a workbook.)

      Screenshot 2019-09-19 at 14.12.28.png

      So far so good... But now I want to create a visualisation that shows the accumulation of shootings over time and the congressional districts for a specific year. So for example, if the year is set to 2018, I want all of the shootings from 1981-2018 to show, but only the congressional districts for 2018. The problem with using Pages and Show History to visualise this is that it accumulates both shootings and districts. For example below, the year is 2018 and it shows all the accumulated shootings but also the accumulation of every congressional district which just comes out to tons of polygons layered on top of each other.

       

      Screenshot 2019-09-19 at 14.28.21.png

       

      But then when I add the year of the congressional district as a filter, it filters out all of the shooting data, as is discussed here. I've tried playing around with calculations but to no avail.

       

      Screenshot 2019-09-19 at 14.31.08.png

       

      Is this even possible to filter by one dimension and use pages for another? Is there a way to make this happen?