4 Replies Latest reply on Sep 6, 2016 5:33 AM by Dan Armstrong

    How to organize points on concentric circles?

    Dan Armstrong

      Hi,

       

      I have a bunch of data points falling into three big groups, with each group divided into several smaller groups.

       

      I want each of the three groups be represented as a concentric circle, with each of the subgroups in the circles separated out (using a different color and with space setting it off). You can see what I'm trying to do in the screenshot below.

      I am almost there. But not quite. Two problems I can't seem to resolve.

      First, in each circle, most of the subgroups are distinct -- colored differently and set off with spaces -- but there is always one that is mixed up. In the inner and middle circles, it's on the right; in the outer circle, it's on the lower left. In those segments, somehow my subgroup points are being computed adjacent to each other.

       

      Second, I can't seem to get spaces between all of my subgroups.

       

      To compute the circles, I am getting my X coordinate from cos(2pi k / n) and y from sin(2pi k / n), where k is the sequence of points in the circle (0, 1, 2, 3....n) and n is the total number of points (43, 77 and 86). I've fooled around with K and N to try to get separation between the groups, but without much success.

       

      This feels like a very simple problem compared to the mapping stuff I've seen. It's just a circle. But I am flummoxed. Any idea on what I'm doing wrong? Workbook attached, as well as the underlying spreadsheet.

       

      Thanks for any advice.

       

      Dan