This interactive visualization of the VAST Challenge 2019 dataset uses React and D3 v7 to render a stylized SVG map of St. Himark. It displays city districts as filled polygons alongside sensor locations marked by circles. The code implements a custom map projection using `d3.geoNaturalEarth1` and `d3.geoPath` to draw geographic boundaries, while sensor data is loaded from a remote CSV file using `d3.csv`. The interface is built with React components, with styles managed through CSS.