Fork of ILINet Flu Surveillance Data
This visualization displays national ILI (influenza-like illness) total cases per week, with separate curves for each year from 2015 to 2019, enabling year-over-year comparison of flu season patterns. The chart uses an unordered color scale for the year field, which complicates reading since there is no intuitive ordering like "darker is more recent." Built with vega-lite-api, the code aggregates ILITOTAL by year, region, and week, then renders points with tooltips showing the year. Data originates from CDC FluView Interactive, loaded via d3.csv, and rendered with a custom config for improved label and title readability.