This visualization shows chlamydia rates by U.S. county, using the FIPS code as an identifier and the rate per 100,000 people as the quantitative value. The data is loaded from a CSV file and rendered as an SVG choropleth map, with counties colored according to their reported chlamydia rates. Built with D3 v4, the visualization uses a threshold or quantize scale to map the rate values to a color range, likely from light to dark, to convey the geographic distribution of chlamydia cases across the United States. The map provides a county-level view of disease prevalence, with missing values for some counties left blank. The code is organized for blockbuilder.org and uses the standard D3 projection and path rendering for the map.