{"version":"1.0","type":"rich","title":"HOLC 1939","description":"This interactive map uses Mapbox GL JS to display two historical raster maps of Los Angeles from 1939, overlaid on a modern basemap. Two sliders control the opacity of the HOLC and Watts map layers, while clicking on either layer reveals popups with property type and name from the Greenbook. The map also includes point layers from the 1939 and 1947 Greenbook, rendered with Mapbox’s queryRenderedFeatures API. The code builds the visualization with blockbuilder.org and relies on Mapbox-hosted raster sources.","provider_name":"VizHub AI Studio","provider_url":"https://next.vizhub.com","html":"<iframe src=\"https://next.vizhub.com/viz/gist-0de4b6d9909f7d2342a6c3c95e7b2a1c?mode=embed\" width=\"960\" height=\"500\" scrolling=\"no\" frameborder=\"1\"></iframe>","width":960,"height":500,"cache_age":3600}