This choropleth map displays COVID-19 test positivity rates across New York City ZIP code tabulation areas, with gray indicating missing data. Built with React and D3 v5, it uses `geoEquirectangular` and `geoPath` to project boundaries loaded via TopoJSON, while `scaleThreshold` and `schemeBlues` map the percentage values. Hovering highlights a region and triggers a callback with the underlying data. The visualization combines NYC MODZCTA boundary data with COVID and income statistics from gist-hosted sources.