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

These charts shows the student level: freshman, sophomore, junior, senior, or unclassified of students that transfer from Maryland community colleges to University System of Maryland institutions. According to the notes on the data by the University System of Maryland, the transfers are the number of undergraduates enrolled for the first time at the institution with known prior undergraduate post-secondary experience. The students may or may not have transferred credit.

Treemap Maryland Community College Transfer Students by Student Level

Source: University System of Maryland, IRIS, Maryland Community College Transfer Students by Student Level, Fiscal 2020

Drill Down SunBurst Maryland Community College Transfer Students by Student Level

Source: University System of Maryland, IRIS, Maryland Community College Transfer Students by Student Level, Fiscal 2020

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

Since I was able to get the sunburst chart to finally work properly. I decided to take a look at the data I entered. For some reason, the enrollment for winter 2021 is really low (COVID and short term?), so I decided to pull numbers of a more typical term (still COVID) to get a better idea of actual enrollment. I wrote the code in a text file, so I have not yet taken a look at the chart. However, I know from just looking at the data that Prince George’s County has the highest headcount enrollment. This is logical because Bowie State University is located in Prince George’s County.

Bowie State University Spring 2021 HeadCount Enrollment

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

Getting the COde to Render Locally

In my last post, I said that I could not get the Sunburst Chart to render properly out of CodePen. I walked away with plans to go to bed. Getting ready for bed I did a few minutes of googling and found a Reddit post from three years ago that explained my issue. Apparently, since it was running locally I need to add “https:” prior to the resources in the HTML part of the code.

Below I have quoted partly how it was explained on the Reddit post. Basically, without the https:, which is sometimes assumed and can be assumed when it is running off CodePen, the computer does not know what it looking at. Thus, my code will not render. Since I am new to this and kind of just trying to make things work, I will be adding in the “https:”


…when you don’t use an explicit scheme, then your brower will use the scheme of your page. … This is also why this gave you problems when running locally: if your page is served under file:///some/path/to/your/file.htlm then the url// resolves to file://, which doesn’t exist. …

When I was running the code without the “https:”, it would just spin its wheels. There was no error code.

SUnBurst Chart BOWIE STate Enrollment

Source: University System of Maryland, IRIS

Thoughts about SunBurst Chart

I need to type in all my data before I can decide if I like a chart. The Sunburst chart is kind of interesting, it allows for drilling down of data, which I really like. The issue with the particular chart is that there is so much data the chart is kind of difficult to read. In my first version, I did not have the in-State enrollment divided by region and it was even harder to read.

Again I have run into the issue of not being able to get an Amcharts graphic to render on my site. I can make it render in CodePen, but when I export the “pen” it will not render locally. I also can not get it to render using the WordPress plugin for Amcharts. So I am going to park this here until I can figure out why I can not get it to render.

See the Pen amCharts 4: Sunburst Diagram with my data and regions no zero by Caroline (@New-Fish) on CodePen.

Source: University System of Maryland, IRIS

In my previous post, I built my first treemap using Amcharts. Today I built another treemap, this one is 3 levels deep. I am unsure about the presentation of the data in this manner, it may not actually be very useful. However, since I was able to successfully explore building a multi-level treemap using the Amcharts demo I will call it a success.

In this example, I was able to get the level 1 labels to appear, which I was not able to figure out yesterday.

Source: University System of Maryland, IRIS

Today I am testing out a treemap that I made in Amcharts. I made a treemap of the students that transfer into the University System of Maryland in 2020. The top layer is the education sector, the second layer is the institution. I am still having a bit of trouble getting it to behave as I would like. I would like the second layer names to appear in the boxes, but I can not seem to get it to work as it does in CodePen. Again I got it to work in CodePen using an Amcharts demo as a model, but again I ran into an internal 500 error when I tried to transfer the code over. So I rewrote the code keeping out the pieces that were not rendering properly.

The treemap clearly shows that there are a large number of transfer students from the US Armed Forces, in part because of the University of Maryland Global Campus. I may make another treemap that excludes transfer students from the University of Maryland Global Campus.

Second Layer Hidden

Source: University System of Maryland, IRIS

I figured out how to show the size of the institutions before drill down, but not the institution names. There is likely a simple way to show the labels on a treemap in Amcharts, but I have not yet figured out how. I think that I like the first style better, but I will need to test both versions.

Second Layer Shown

Source: University System of Maryland, IRIS


I realized while I was digging into the data further that I missed the 16,362 students that transferred from “other” out-of-state institutions and 5 students that transferred from “other” MICUA/MD private institutions. I missed them because the institution details is only provided for the top 15 institutions in each of the drill-down categories.

Today I am taking a look at the dual enrollment data published by the Maryland Longitudinal Data System (MLDS) Center.

According to the data, 85% of 12 graders in the 2018-2019 student year who earned dual enrollment credits between 9th and 12th grades (academic years 2015-2016 to 2018-2019) enrolled in college in fall 2019. Of those who enrolled in college: 36% enrolled in an in-State community college; 35% enrolled in an in-State (public or private) four-year college; and 28% enrolled in an out-of-state college. This is showed in the Sankey diagram below.

I wish I could match up the dual enrollment students with the general student population. It would be nice to see if the behavior of students that dually enrolled differs from the general student population. I will take a deeper look at the data in the future to see if I can use math to make any conclusions.

As of yet MLDS Center has not yet published the general college enrollment data for the 2018-2019 cohort year. However, typically, 50% or less of high school graduates immediately enroll in college. Thus, students that participate in dual enrollment programs (unsurprisingly) seem to enroll in college at a higher rate than students generally.

Source: Maryland Longitudinal Data System Center, dual enrollment courses and credits: 2018-2019

According to the data set, of the 6,237 students that enrolled in-State following participation in a dual enrollment program, 3,012 in-state students, or 48%, enrolled at the college of dual enrollment. A further 2,936 in-state students, 47%, participated in a dual enrollment program at a community college and enrolled at an in-state four-year institution.

notes about the Data

  • The data shows data on the college enrollment patterns for 2018-2019 12th grade high school students with dual enrllment activity at any point between 9th and 12th grade. The initial population was selected by identifying studetns who had noth a high school enrollment and a college enrollment recored in the 2018-2019 academic year (fall to spring). Summer enrollment information was excluded from this analysis.
  • This diagram is the result of me exploring the limits of the data and the graphing software. The numbers and math have not been checked.

Short answer. Yes, free-and-reduced price status likely impacts college segment of initial enrollment. See the pretty Sankey diagram below that shows the college segment of initial enrollment for high school graduates by free- and reduced-priced meal (FARMS) eligibility status. However, read my data notes below before making any conclusions.

Most notably 47% FARMS eligible high school graduates failed to enroll in any college segment compared to 24% of non-FARMS eligible high school graduates. Also, 10% of FARMS eligible high school graduates initially enrolled in an out-of-state college compared to 24% of non-FARMS eligible high school graduates.

Click here if you can not see the diagram.

Long answer. As an analyst, I can think of a long list of reasons why this data does not answer this question. The first being is that the data source does not list actual numbers, just percentages. So I had to back into the numbers I used in the diagram. However, due to rounding, the numbers do not add up to the proper totals. If this was for real analysis I would try to get the actual numbers. I need to use numbers, even if they are not quite correct to get the diagram to render properly.

But for this project, I am just attempting to see if I can code this type of diagram and getting a general sense of what the diagram would show. On that end, it is a success. I can do the coding, I am sincerely hoping that you can see the diagram above right now. I also think I really like the visual effect. I think it works well when you have a few categories for each node.

Notes about the Data

  • The number of students are estimates from the percentages published by the Maryland Longitdinal Data System Center. I have not fully checked my calculations, this is primarily for me to learn how to create the diagrams using the software. I am also attempting to learn which types of data visulizations I find useful and worth pursuing. I also am trying to better understand the data.
  • Due to rounding in the data source the numbers do not add up to the correct totals. This is just for a general idea of the data, not for specifics.
  • Some notes adapted from those provided by the Maryland Longitudinal Data System Center, all errors are my own.
  • The number number of years following high school graduation impacts the initial postsecondary enrollment numbers. Graduates who enrolled in Private Career Schools or Continuing Education and Training Certificate sequences are not included.
  • This dashboard uses “initial enrollment,” which counts only the first enrollment of a student after graduation. For example, a student graduates high school, enrolls in a summer community college course, and then enrolls in an out-of-state college in the fall. The initial enrollment count for that student is one in-state enrollment. Other methods of counting enrollment may count that student as one in-state and one out-of-state enrollment. Accordingly, when reviewing, and especially when comparing post-secondary enrollment reports, it is important to understand how the enrollments are being counted.
  • The number of high school graduates reported on this dashboard includes: (a) only the counts of 12th grade graduates; and (b) eliminates any duplicate graduation recordsSome numbers are rounded or estimated due to data suppresssion. For general illistrative purposes only.