This pie chart visualizes the proportional distribution of entry-level, mid-level, and senior-level data professionals across geographic locations, based on aggregated salary and COVID-19 population density data. The chart aggregates population density values from `covid.csv` for each location, then uses `d3.csv` to load and `d3.group` to organize the data. Using `d3.pie` and `d3.arc`, the visualization renders SVG arcs with `d3.schemeCategory10` for color encoding, placing location labels at each arc’s centroid via `arc.centroid()`.