This visualization displays the number of stroke-related deaths per California ZIP code for 2016, using a choropleth-style map where each ZIP code area is rendered as a red SVG path. The map is projected using a Mercator projection centered on California, and users can zoom and pan the view. The code loads geographic boundaries from a public GeoJSON repository and joins them with mortality counts from a local CSV file using d3.csv and d3.json. Interactive zooming is handled through D3's zoom event, while d3.geoPath generates the map shapes.