3 Replies Latest reply on Sep 22, 2017 12:03 AM by Caroline Beavon

    Dual axis map - removing NULL values from filters

    Caroline Beavon

      Well this is a pickle:


      I've created a dual axis map in desktop (for eventual use on Public) with:


      - polygon shapes (local authorities) filled with deprivation data (which is on a separate source)

      - locations shown as points on top




      I understand that both these data points need to come from the same data source so I've merged them into the same spreadsheet using LAT and LONG as a shared column.

      (info: the data will eventually be coming in via a database, which I currently cannot access so I'm working off an Excel export with the same fields (so the transfer across later on *should* be simple.!


      I've managed to hide some of the ugly NULL values on the map with transparent shapes, however, when I create filters, they contain NULL values that must be selected or the deprivation data disappears (because the shape file entries do not contain the same information as the location entries).


      I think the issue is with how I've got the data combined but I can't see a way round it. 


      It's an early stage so I could change how the deprivation and shapefile data is arranged (i.e. I could have it inserted into the location database, or some other solution)


      Any suggestions welcome - going in circles a bit here


      Thank you



        • 1. Re: Dual axis map - removing NULL values from filters
          Carol Au

          I'm not sure if this will work but could you try making a set that excludes the Nulls for the filter?

          • 2. Re: Dual axis map - removing NULL values from filters
            Shaik H

            Hi Caroline,


            Please find my approach

            1. Right-click a dimension and select Duplicate.
            2. Drag the original field to the Filters shelf and include all values.
            3. Right-click the dimension on the Filters shelf and select Show Filter.
            4. Open the drop-down menu in the upper right corner of the filter card and then select Only Relevant Values.
            5. Place the duplicate field on the Filters shelf, select all values except the null values, and then click OK.




            • 3. Re: Dual axis map - removing NULL values from filters
              Caroline Beavon

              Thank you to both of you for your ideas (and for everyone else who helped out) - sorry for the slow reply - I've been trying to work out a solution for this one!


              Sadly excluding the NULLS removed the secondary dataset, so I needed a way to keep them in, but not have the NULL in the filter.


              The solution involved going outside of Tableau and using Mapbox  - I created a polygon map in Mapbox (with the deprivation data) which I then used as a background map within Tableau. Having only one dataset running in Tableau meant I removed the NULL issue.


              It has some downsides - the deprivation data values can't  be 'accessed" but it's role was always to give a guide so it works in this instance.


              Thanks again for all the help and ideas.