Variants
This visualization aggregates COVID-19 variant counts by location using a bar chart, with each bar’s length representing the number of sequences and color encoding the variant type. It loads data from the Our World in Data COVID-19 variants CSV via the `d3.csv` method. The chart is built with the Vega-Lite API, configured through `vl.markBar`, encoding fields for location, sequence count, and variant, and rendered using `vega` and `vega-lite` libraries with tooltip support from `vega-tooltip`.