{"version":"1.0","type":"rich","title":"Census Tract Quadtree Contours","description":"This visualization uses a quadtree-based indexing technique to render U.S. Census Tract demographic data as an interactive, zoomable map. It precomputes a uniform grid of sampled values from tract polygons indexed in an R-tree, aggregates those values into a quadtree, and then renders the visible quadtree nodes as colored rectangles using Canvas. The map displays racial composition data (e.g., white, black, Asian populations) from the 2023 ACS, with countries and graticule lines from the VisionsCarto world atlas. Built with D3.js, React, and Turf, it demonstrates a performant alternative to traditional choropleth rendering for large polygon datasets.","provider_name":"VizHub AI Studio","provider_url":"https://vizhub.com","html":"<iframe src=\"https://vizhub.com/viz/99c48f3838f747dca588842f655c2fcc?mode=embed\" width=\"960\" height=\"500\" scrolling=\"no\" frameborder=\"0\"></iframe>","width":960,"height":500,"cache_age":3600}