3 Replies Latest reply on Feb 18, 2019 6:52 AM by Ken Flerlage

    Radial chart starting position trouble

    Sue Grist

      I've followed the fantastic blogs by Kevin Flerlage (https://www.kevinflerlage.com/2019/02/whos-afraid-of-big-bad-radial-bar-chart.html)) and Ken Flerlarge ( https://www.kenflerlage.com/2017/11/beyond-show-me-part-2-trigonometry.html)) to create a radial chart. Ken Flerlage, kevin flerlage I've been able to create the chart, but the radial lines are not starting where I'd like them to start, and not going in the direction I'd like them to go.


      Here's a snapshot:



      This is weekly data over 5 years. Week 1 is the data for week 1 for all of the years summed together. This means Week 1 is not an actual date field, it is simply a Dimension.


      I'd like week 1 to show up at the top center point, and then week 2 immediately after it to the right, like a stopwatch going from 0 seconds, to 1 second, 2 seconds, etc.


      I realize this means I need to tweak the trig calculations, but I don't know how I need to change them.


      Attached is my Excel file and my twbx file (v2018.3).


      How can I make this data follow the structure I'd like?



        • 1. Re: Radial chart starting position trouble
          Ken Flerlage

          Okay, so the first issue is your multplier in SG Angle in Degrees. Since you have 53 points, each angle will be spaced 360 degrees/53 which is 6.79245 degrees. So, you'll need to adjust that calculation. That will get us to a point where the bars are aligned a bit better:


          But we still have a couple of problems. I know you want to put week 1 at the top then go around clockwise, but to do that, I'd suggest we first get week one to appear at 0 degrees (where week 53 is currently) as that will make it easier for us to rotate it 90 degrees counter-clockwise. To do that, change your formulas in the SD Angle in Degrees field (in Excel) to "=(A2-1)*6.79245283018867" then drag it down to all the rows.

          Week 1 will now show 0 degrees. Week 2 will show 6.79, etc.

          Okay, so now week 1 is at 0 degrees. Next we'll want to basically rotate it counter-clockwise 90 degrees in order to have week 1 at the top. To do that, adjust the Angle calculation in Excel to "=90-(A2-1)*6.79245283018867". Note: This will result in some negative degree values for some of your angles, but that's okay. -270 degrees, for example, is the same as 90 degrees.


          With that adjustment, you should now have the placement you need:


          Does that make sense?


          I've attached the workbook and the spreadsheet.

          1 of 1 people found this helpful
          • 2. Re: Radial chart starting position trouble
            Sue Grist



            WOW! Thank you for your quick, thoughtful, and really well explained help with this.