ILINet Flu Surveillance Data
This visualization displays national ILI total flu cases from 2015 to 2019 as overlaid annual curves, highlighting yearly patterns and enabling direct comparisons. The chart uses an unordered color encoding for the ordered year field, which impairs readability because viewers cannot infer temporal order from color alone. Built with vega-lite-api and d3.csv, the code loads data from a Gist containing CDC FluView Interactive data, with vega-tooltip providing interactivity and a custom config for axis styling.