1 2 Previous Next 19 Replies Latest reply on Oct 31, 2015 9:53 PM by Antonio Buono

    Ternary Plots

    Dani Schmid

      Hi,

      in quite a few branches of science ternary plots (http://en.wikipedia.org/wiki/Ternary_plot) are a very useful way to illustrate mixtures between 3 end members. Any way this can be done in tableau?

      Cheers,

      Dani

        • 1. Re: Ternary Plots
          Alex Kerin

          Not easily (if at all) - what would the data look like going into one?

          • 2. Re: Ternary Plots
            Dani Schmid

            that wikipedia link has an example (copied below). One could maybe "abuse" a normal scatter plot for this by re-projecting, but that would not be very pretty. Or maybe one could (ab)use a map plot, again through re-projecting.Something similar is done on http://wvaughan.org/ternary-plot.xls

             

            Sample #     Organic matter     Clay     Sand     Notes

            Sample 1     80%     10%     10%     Because organic matter and clay make up 90% of this sample, the proportion of sand must be 10%.

            Sample 2     50%     40%     10%     The proportion of sand is 10% in this sample too, but the proportions of organic matter and clay are different.

            Sample 3     10%     40%     50%     This sample has the same proportion of clay as in Sample 2 does, but because it has a smaller proportion of organic matter, the proportion of sand must be larger, because all samples' proportions must sum to 100%

            • 3. Re: Ternary Plots
              Alex Kerin

              That is what I was thinking - XY or map with a background. No other way to do it I don't think. With a map you may be able to use shapefiles to define areas.

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              • 4. Re: Ternary Plots
                Jonathan Drummey

                I imagine that doing a calculation outside of Tableau to generate the paths for custom polygons could work. Jerome Cukier created a tree map in Tableau doing that sort of thing: http://www.jeromecukier.net/blog/2012/04/19/treemaps-in-tableau-can-be-done/

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                • 5. Re: Ternary Plots
                  Dani Schmid

                  This looks like it could do the trick. Thanks! Native tableau implementation  would be better as it would take care of axes labeling, tick marks etc.

                   

                  Somewhat related to this: How do I combine plot types? I have an example data set below. X&Y could be used to make the triangle polygon, X2 and Y2 should then be plotted over it as points. This must be trivial, but I only manage to make either polygons or points (I am brand new tableau) ....

                   

                  X     Y      X2      Y2

                  0      0     0.2     0.1

                  1      0     0.5     0.4

                  .5     1

                  0      0

                  • 6. Re: Ternary Plots
                    Richard Leeke

                    How about something like this:

                     

                     

                    There's a bit of ugliness with null values in order to draw the data as polygons on top of the axes as lines - but it's native Tableau so you get tooltips and stuff.

                     

                    I've attached the spreadsheet with the data for the axes and dummy shapes and the original workbook without extracts so you can see how it works.

                    • 7. Re: Ternary Plots
                      Alex Kerin

                      Nice Richard.

                      • 8. Re: Ternary Plots
                        Dani Schmid

                        Nice! With the exception that the barycentric coordinates are not shown along the subvertical  triangle edges this is near perfect. Thanks a lot!

                         

                        (forget about my questions regarding how to plot different types of data on the same graph, I start to get the hang of it, dual axis, multiple marks, ...)

                        • 9. Re: Ternary Plots
                          Jonathan Drummey

                          Impressive!

                          • 10. Re: Ternary Plots
                            Richard Leeke

                            I did play with putting the coordinates in along the edges using labels:

                             

                            ternary.png

                             

                            That looked fine with just the axes, but as soon as I tried overlaying the data with the dual axis I got labels up that vertical line at x=0. You might be able to suppress them with a bit more effort, but I didn't have the time to try...

                            • 11. Re: Ternary Plots
                              Richard Leeke

                              I had another quick play with putting the coordinates in - I realised I could just suppress the null values with:

                               

                              Analysis->Special Values->Hide

                               

                              That works well and it ends up looking fine. I republished to Public, so the embedded viz above now has coordinates. It also has scroll bars but I couldn't be bothered to fix that.

                               

                              I had to mess around with the order of the data points to get the coordinates to display correctly, so I've attached the updated spreadsheet.

                               

                              I also experimented with the axis grid with and without nodes at all of the intersections of the grid. I think it works better with them there - the tooltips on mouse-over (and the different coloured grid lines) really helped me navigate the grid - I think it would take a while till you could read one of these at a glance.

                              • 12. Re: Ternary Plots
                                Dani Schmid

                                the coordinates on the left side are wrong, i.e. inverted.  They should be the same as on the right side, increasing to the top of the triangle. otherwise this is fantastic! thanks again.

                                • 13. Re: Ternary Plots
                                  Richard Leeke

                                  No, it has to be cyclic like that otherwise the apex would be 200%.

                                   

                                  Here's an image from that Wikipedia article you pointed to in the original post.

                                   

                                  726px-Ternary_plot_1.png

                                  • 14. Re: Ternary Plots
                                    Dani Schmid

                                    ok, my mistake, I should have checked this better. I have never seen it used this way. Searching around a bit shows that it is indeed often used the way you have implemented it. So I learned something. The way I usually use it is shown in the picture below (from the same webpage). These diagrams are used to, for example, show the properties of a sedimentary rock. The main constituents are clay and sandstone. I can put any mixture between the two of them as a point on the baseline, with 100=all sandstone and 0=no sandstone (i.e. 100 clay). If these rock also contains organic material then we need the other dimension/direction. If we have 100 organic material then we have no clay or sandstone.

                                    http://en.wikipedia.org/wiki/File:Ternary.example.axis.1.jpg

                                    another example is

                                    http://0.tqn.com/d/geology/1/7/M/N/1/600QAPplutonic.jpg

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