An Aster Plot for the Holidays

Yesterday was Christmas and for those who celebrate Christmas, I hope you had a very happy day. However, I just wanted to ask this. Why do we wait for Christmas to be nice to one another, to wish our fellow man peace on earth and goodwill to all men? And do we really mean it or do we just go back to our old ways the day after. Do we need a holiday to be nice to each other? Why cannot the Christmas spirit spread throughout the year? And why does it have to be tied to a religious holiday. Do we need a religious holiday to tell us when to be nice to others?

On a similar note, New Year’s resolutions are coming up in another week. Could we all possibly resolve to act a little more like Christmas every day of the year? Or is that just as hard as resolving to lose weight?

Anyway, since many of you are on vacation anyway this week, I’m going to do just a short blog on the Aster Plot visualization for Power BI. This visualization, like many of the others I’ve talked about can be found on Microsoft’s Power BI Visualization Gallery page. When you click on the Aster Plot tile, the following diagram displays telling you a little about the visualization which as they state in the description is related to a donut chart. However, unlike a donut chart which defines the size of the donut segment on the value associated with that segment much like a pie chart, an aster plot uses one dimension to define the segments and each segment is equal in the amount of the arc it uses. The value associated with the segment defines the radius of the segment instead. Let’s see how this might work with some of the sales data by product category from Contoso.

I’m not going to go through all the dialogs that appear when you download a new visualization. I’ve done that before. So if you are joining in for the first time, check back through some of my previous blogs for details on that.

After the visualization is downloaded, I can load it into my Visualizations toolset/panel by clicking the ellipsis (3 dots) at the bottom of the visualizations panel.

Power BI will display a warning to caution you about importing custom visualization, so you should always do this on a test machine first to make sure they do not cause any issues. Just because it is on a Microsoft page does not mean that it is safe to use and does not violate any privacy concerns.

Next, I loaded my Contoso data and displayed the Sales Amount by Product Category as shown in the table below. (Again, if you do not know how to do this is Power BI, I’ve covered this several times in the past several months.) I should mention that I specifically sorted the sales data in descending order for this visualization.

Then with my table selected, I can click on my new visualization, the Aster Plot which displays the chart shown below.

Notice that if I hover over any of the segments, a box appears that tells me the product category name along with the corresponding sales amount for that category. One of the things that I don’t particularly care for is that the name of the dimension appears in the center of the chart and apparently behind the arcs so some that some of the name is covered by the chart. I wish I could move the dimension name either to the top of the bottom of the chart at the very least. Of course I could customize the name to make it smaller or to add spaces between the words back on the data page, but for this demonstration, I didn’t feel the need.

You can have other charts on the same page like the one shown here that displays the Sales Amounts by calendar year for Contoso.

Like other visualizations, I can click on any of the Aster plot segments to select that category and the column chart to the right will automatically update to highlight the annual sale for the selected category while still showing in a lighter shade of the column color to total annual sales.

Similarly, I can select a year and the Aster plot will be redrawn to display the relative sizes of each of the categories as shown below.

Well, that is all I’m going to cover for this week because it is time to get back to end-of-year celebrations, visiting relatives, after-Christmas sales, and all those things.

C’ya next year.