CovidPulse is an interactive map that shows Unite States coronavirus trends at the local level, since February, updated daily.
0:14 Johns Hopkins University U.S. County data source
0:40 What is a sparkline?
1:38 Information architecture influenced by “Designing for the Scent of Information” by Jared Spool.
2:25 Trend status coloration by Charlie Frye.
2:45 Outlier counties with large prison populations. The unexpected questions maps help us ask.
3:50 The “second wave” signature.
4:50 The question of universities.
5:10 New York’s severe early rates.
5:48 California’s slow growth.
6:20 The time lag, and other variations, between cases and deaths.
7:09 The trend signatures of cumulative cases.
8:07 The upswing of North Dakota.
8:36 A previous sparkline map visualizing digital security.
9:09 The sparklines of Riley Champine, and its influence on CovidPulse.
10:08 The cumulative case sparklines of Mathieu Rajerison as validation of a concept.
10:37 The power of trend visuals with temporal and geographic data.
Here is a resource if you are interested in mapping with sparklines using the ArcGIS API for JavaScript.