This scatter plot visualizes aggregated COVID-19 vaccination data from the eu_vaccinations.csv file, showing weekly FirstDose counts by vaccine type across European cities. The data is processed using d3.flatRollup and d3.sum to aggregate values by YearWeekISO and Vaccine, with each vaccine type assigned a distinct color via a switch statement. The visualization uses d3.scaleLinear for both axes, d3.axisBottom and d3.axisLeft for labeling, and renders individual circles as SVG elements sized with a fixed radius of 2 pixels. The source dataset includes city names with latitude, longitude, and population information, though the plotted values focus on the vaccination aggregates.