Huidae Cho’s Web Apps

COVID-19 . GitHub repository

Since February 2, 2020

The COVID-19 web map is a Coronavirus Disease 2019 (COVID-19 or 2019-nCoV) cases tracker inspired by a similar web map developed by Johns Hopkins CSSE. They used Esri’s dashboard platform for visualization, and Google Sheets and Esri’s REST API to compile and serve case data. They are doing the hard work of mining case data and I really appreciate their efforts. I wanted to utilize their near-real-time data to create an open-source-based web map using OpenLayers.

1   Symbolizing cases

China has a relatively huge number of confirmed cases compared to other countries, which makes it difficult to symbolize cases around the world more efficiently. For example, as of February 12, 2020, China alone has more than 44,000 cases while other countries or Diamond Princess cruise ship each only has up to about 170 cases, which is only 0.4% or less of the China total. To make these relatively extremely fewer cases visible on the map, initially, I used a logarithmic scale for the radius for all three categories including confirmed, recovered, and deaths, but I found it to be somewhat misleading and agreed with carpiediem’s comments. I kept the logarithmic scale only for confirmed cases and changed the other two radii to the proportion of each to confirmed. It may not be ideal to compare these quantities without the confirmed layer, but I believe that it is better than a logarithmic radius inside another.

I did some experiments using the area, but it was only slightly better than the linear radius.

2   References


Any comments or suggestions are welcome!

Thu Mar 12 20:51:31 2020 EDT

Dr. Cho,

You may want to consider changing the red within the logarithmic radius as it is difficult for those who are color blind to differentiate it from the green background.


Fri Mar 13 19:18:19 2020 EDT

Owen, What about grey (confirmed), blue (recovered), and red (deaths)? It didn’t look good. I just added stroke lines between all three categories.

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