This drill-down sunburst chart shows the breakdown of students that transferred to the University of Maryland College Park in fiscal 2020. The first layer shows the type of sending institution: Maryland Community Colleges; other University System of Maryland institutions; Maryland private institutions, including institutions that belong to the Maryland Univerity and College Association (MICUA); and out-of-state institutions. The second layer shows the institutions. However, since the original data source only shows the top institutions in a particular category, the names of not all out-of-state institutions are captured.

This chart is based on an Amcharts demo for a drill-down sunburst chart. This particular data only had two levels, but additional levels can be added if you have hierarchical data with multiple levels. As with several other charts I have tried making with Amcharts, this chart did not work in their add-in for WordPress. I however was able to add my data using Notepad. Then I saved the document as an HTML file by changing the file extension to .HTML. Then I uploaded the file to the media library for my website. Finally, I used some HTML code on this page to creat a frame and pull up the chart. I explained that process and shared the code I used in a previous post about my experiences making charts and maps with amcharts.

The chart shows that 63.6% of transfer students came from Maryland community colleges. Half (50.3%) of those students from Maryland community colleges came from Montgomery College, which is located in Montgomery County not far from UMCP. Anne Arundel Community College, Prince George’s Community College, and Howard Community College were also the source of a large number of transfer students. The second-largest source of transfer students is out-of-state institutions. For that category none of the sending schools are dominant. The biggest category is “other”.

UMCP Transfer Students in Fiscal 2020 Drill Down Sunburst Charth

Source: University System of Maryland, IRIS

I found code for a drill-down sunburst chart on Amchart’s website. I just popped in the data I had already typed up that has Bowie State Univesity spring 2021 headcount enrollment by area of origin. This version is kind of nice because you can drill down to see the details of the smaller categories. A disadvantage is that you can not see the drill-down categories until you drill down. In the future, I may be able to figure out how to show the hidden layers, but I am not sure if that will be an advantage, it might be too close together to see the categories well.

To drill down to a level click on the pie slice. This will expand the slice to the entire area of the pie. It is rather difficult to explain, it is easier to just play with the chart down below to understand how it operates.

The drill-down sunburst chart goes down to the level provided in the original data. For in-State students, the data shows to the county level the area of origin. For out-of-state students, it shows students from the major surrounding states and the District of Columbia. The states are New Jersey, New York, Pennsylvania, and Virginia. The remaining students are from other states, “foreign”, or of unknown origin.

To make the other sunburst chart look cleaner I divided the counties into five regions: Capital Region, Central Maryland, Southern Maryland, Western Maryland, and Eastern Shore. The regions and the counties assigned to each region are from the “Visit Maryland” website. For this semester Bowie State University had no students from Western Maryland counties, so that region is not on the chart. As with the other charts, I withhold judgment on the chart until I have an opportunity to play with it.

Bowie State University Drill Down SunBurst CHart

Source: University System of Maryland, IRIS, headcount by area of origin