3 Replies Latest reply on Jul 1, 2013 1:37 AM by Dana Withers

    How do I avoid the cartesian product in double axis graph creating extra (incorrect) datapoints

    Dana Withers



      I'm working on mapping on custom backgrounds to create specific views. For example I'm trying to create a floor plan of our company showing teams and people on desks. The teams should really be polygons with colour and the people should have their own name/details on their desk. Another example this could be used for is a Venn diagram (yup horrible things, but someone really wants them).


      My problem is that I have the dataset correct, but I cannot put marks on the polygons. I thought I'd work around that using dual axis and creating both a second X and a second Y axis and using them to plot a scatter plot with all the info I need to show. However, If you use both a second X and a second Y, you get each data point double. How can I avoid that?


      I've created a very simple example and posted it to tableau public:

      Here is the cross tab view showing that I've created a dataset that properly merges two datasets - one for point A and one for point B. They each have their own X and Y axis values and when blended together create 1 row as expected.

      CrossTab view

      Here is the resulting plot with double data points. Tableau is plotting each point against all the combinations of X and Y, resulting in 4 points instead of 2.

      Double Axis


      How can I filter out / hide the plot points that mix primary and secondary axis?


      Thanks !