1 2 Previous Next 19 Replies Latest reply on Jan 11, 2017 10:16 AM by Scott Jenkins

    Can we Smoothen the Spikes?

    ChandraSheker A

      Hi all,

      I have a View in Tableau like below. which is by Day.

       

      Can we smoothen this like the one which i have in an excel version.

       

       

      i dont want to see sharp Edges.

       

      is it possible in tableau?

        • 1. Re: Can we Smoothen the Spikes?
          David Milmont

          I am not aware of a option to smooth out a line chart similar to Excel.

           

          Keep in mind, If you are plotting measured data, the only valid connection between points is a straight line. Smoothing the line will start to introduce visual misrepresentations. You may already be aware of this and okay with it.

           

          If you would like to smooth things out a bit you can always plot a moving average of the data rather than the way you have now. This is done easily with a Quick Table Calculation in Tableau. Creating a Rolling Calculation | Tableau Software

          3 of 3 people found this helpful
          • 2. Re: Can we Smoothen the Spikes?
            Rody Zakovich

            Wanted to reiterate David's point, Smoothed lines will misrepresent that data and make it harder to identify changes in trend. If possible you should avoid using smoothed lines, and their cousin, dashed lines.

             

            Is there any particular reason you want to smooth the lines?

             

            Regards,

            Rody

            2 of 2 people found this helpful
            • 3. Re: Can we Smoothen the Spikes?
              ChandraSheker A

              Yeah, my end user dont want to see the spikes when i am Viewing the data by day.

              • 4. Re: Can we Smoothen the Spikes?
                Rody Zakovich

                My best suggestion would be to explain to your user that smoothing the lines distorts the data.

                 

                Creating these smoothed lines might resolve the requirement now, but it will cause issues in the long run, as your user will not be able to make truly Data Driven Decisions.

                 

                Smoothed lines downplay changes in the trend, which makes it harder to identify slight variations, and see the true significance of larger, more impacting spikes.

                 

                Regards,

                Rody

                1 of 1 people found this helpful
                • 5. Re: Can we Smoothen the Spikes?
                  Shawn Wallwork

                  OK, I really, really tried to stay out of this one, but....

                   

                  An x-period moving average (smoothing) is a perfectly legitimate technique (tool) to help viewers understand what is going on with their data. It's best if this 'smoothing' is overlaid over the original 'sharp edged' data, so the smoothing effect is obvious in relation to the 'raw' data. But just like trend lines, a moving average is just another tool to help us make sense of otherwise visually incomprehensible data.

                   

                  We use many other tools (color-coding, size, bollinger bands, logarithmic trend & scales, et. al.). Labeling one of the more common tools as 'distorting' is, well, taking away a perfectly legitimate tool that helps us better understand our data. The job of the Data Analyst seems to me to be the person who understands how these various tools & views shape, and possibly distort, the understanding of our data. And guard against this 'misinterpretation'. A moving average is not necessarily a distorted view of a data set, any more than a change in scale is a distortion of 'reality'.

                   

                  If you are only wanting a pure view of your data, then a text table of zeros and ones is your best option for displaying raw data (and it could be argued that even that is a distortion). It certainly would be completely incomprehensible.

                   

                  --Shawn

                  3 of 4 people found this helpful
                  • 6. Re: Can we Smoothen the Spikes?
                    ChandraSheker A

                    Thanks, I tried the moving average. i works for me

                     

                    But the Starting point of the view drops to 0. how can i maintain in my view?

                     

                     

                     

                    like above.

                    I was to filter the view to see last 5 months.

                    • 7. Re: Can we Smoothen the Spikes?
                      Rody Zakovich

                      Great points Shawn!

                       

                      Yes Moving average as a way to smooth data is a legitimate technique, as long as the User is not perceiving those values as actuals for the designated periods of time (Months, Years, Etc.), I.E. they understand that they are looking a running average over X Partitions. But I *believe* we are making the same argument. However, I think you explained it better than me!

                       

                      Regards,

                      Rody

                      2 of 2 people found this helpful
                      • 8. Re: Can we Smoothen the Spikes?
                        David Milmont

                        You can remove the starting point that is 0. Right click your calculated field with the moving average table calculation. Then select 'Edit Table Calculation'

                        You should see this now. Select the check box 'Null if there are not enough values'

                        This should solve your issue.

                         

                        You will notice that this will introduce null values to your worksheet as indicated in the bottom right of your visualization.

                         

                        You can hide this by selecting 'Hide' under 'Special Values':  Analysis > Special Values > HIde

                        • 9. Re: Can we Smoothen the Spikes?
                          Shawn Wallwork

                          Right-Click the point at the zero, and click Hide.

                           

                          --Shawn

                           

                          EDIT: Or what David suggested.

                          1 of 1 people found this helpful
                          • 10. Re: Can we Smoothen the Spikes?
                            Shawn Wallwork

                            And then there is the question: How much do you want to 'smooth' them by:

                             

                            And will this give you any usable insight(s) into your data?

                             

                            Cheers,

                             

                            --Shawn

                            1 of 1 people found this helpful
                            • 11. Re: Can we Smoothen the Spikes?
                              Manideep Bhattacharyya

                              Smoothing.png

                               

                              Dear ChandraSheker - You can use this for damping spikes as we did for BSE Sensex. You can present this. This has a parameter control of damp as well.

                              1 of 1 people found this helpful
                              • 12. Re: Can we Smoothen the Spikes?
                                Tharashasank Davuluru

                                Hi Chandrasekhar,

                                 

                                I have  identified the issue of outliers being included in the report charts which skews the results. We need to eliminate the outliers. This will also work in your case.

                                 

                                Correct me if iam wrong.

                                • 13. Re: Can we Smoothen the Spikes?
                                  Rody Zakovich

                                  If you decide to take the route above and overlay a rolling average with Bollinger Bands, then you could also follow this tutorial to give it a cleaner look

                                   

                                  Tableau Tip: Make great looking band lines with area charts

                                   

                                  Note, this is different than smoothing a line for sake of aesthetics (Which is a misrepresentation), this is showing actuals, but giving more context into standard deviation and rolling average. It is important that the user understand this, using well crafted and descriptive titles help a lot with this.

                                   

                                  Regards,

                                  Rody

                                  1 of 1 people found this helpful
                                  • 14. Re: Can we Smoothen the Spikes?
                                    Tharashasank Davuluru

                                    Hi ,

                                    Thank you very much Rody.

                                    But removing the outliers will help us to achieve the above task right?

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