3 Replies Latest reply on Mar 22, 2013 11:32 AM by Allan Walker

    Getting UK Geographies into Tableau (accurately!)

    Alex Lea

      Afternoon

       

      I've been scratching my head over getting UK geographical data into Tableau since we started using it but have been unable to find a definitive answer. Until now. Apologies if someone has already beat me to the punch, but hopefully this could help a few people out.

       

      Because Tableau uses Lat/Lon projections in it's mapping, any UK data stored in British National Grid format has to be tinkered with in order to get the data into Tableau accurately enough to use the streaming background maps. We use MapInfo for mapping in the office, which allows you to save a layer in an alternative projection. The trouble is selecting the correct projections as there are loads of Lat/Lon projections.

       

      Saving as a standard Latitude/ Longitude projection means that the points you bring in to Tableau will be off by a few hundred meters, which although not a huge problem at a high level, if you;re plotting postcodes etc, the results can be way off.

       

      To get round the problem, the correct projection to save your layer to is "WGS 84". From there, you can extract the coordinates (for points) or use Joe Mako's invaluable tutorial to get the polygon attribute data out of the layer and import it into Tableau without any distortion:

       

      Preprocess shapefile for Tableau on Vimeo

       

      Again, hopefully this will help UK Tableau users who have been having trouble getting their geographical data into Tableau.

       

      Feel free to add any questions or comments below. I only know how to get the data in from MapInfo, so if anyone knows how to do it with other mapping software, just include the instructions below.

       

      Alex