4 Replies Latest reply on Mar 23, 2018 2:13 AM by naresh.suglani.0

    How to select polygons individually on a shapefile map?

    naresh.suglani.0

      So I loaded a shapefile into Tableau together with a point file using a technique described by Sarah Battersby but all the polygons on the shapefile cannot be selected or viewed individually. If I turn off aggregate measures then the shapefile disappears.

       

      Workbook attached.

       

      Any ideas?

        • 1. Re: How to select polygons individually on a shapefile map?
          Sarah Battersby

          Hi Naresh,

           

          With your polygons - drop the Name dimension from Districts.shp onto Detail and the polygons will disappear.  You'll see a little icon show up in the lower right corner saying that you have a ton of Nulls - click on this and select 'show at default location' and they should re-appear on the map and be separated into individual polygons.  For some reason, I had to click 'show at default location' twice, but it did work...

           

          Workbook attached.

           

          • 2. Re: How to select polygons individually on a shapefile map?
            naresh.suglani.0

            Excellent, thank you Sarah. I've only ever come across that screen above one before so I'll make a note of it now as I'll probably be using it again in the near future.

             

            Is there any way currently to any spatial analysis on this workbook to select all those postcode polygons within a certain radius of one which has a point inside it?

             

            Or is that only in future upcoming versions of Tableau?

            • 3. Re: How to select polygons individually on a shapefile map?
              Sarah Battersby

              Hi Naresh,

               

              Future versions of Tableau will definitely have spatial intersection included so that you can connect points to specific polygons that they fall inside.  Many other spatial analytic tasks are on our radar, and being able to do selections by location are something I've heard requests for before.   If you can boil the calculation down to using attributes in the data table, there are some ways that you can do selections based on distance from a selected location.  I wrote up an example using some point data as part of an answer to another forums question (How to create a cumulative line chart for map distance ) that might help you think of a way to do this. Essentially I used a parameter to identify origin location and then a calculated field that compared the lat/lon of the selected location (from the parameter) to the lat/lon of the other rows in the table and return a True/False of whether the point was within a set distance of the selected. 

               

              That should give you some places to start thinking about the problem.

               

              -Sarah

              Tableau Research

              • 4. Re: How to select polygons individually on a shapefile map?
                naresh.suglani.0

                Thanks Sarah, thanks for the link. I will definitely give that a read. I've used the True/False method before with a parameter to identify those locations, as you mentioned above.

                 

                Hopefully we'll get the new version of Tableau here once released.