Let's make a map of US-counties with D3.js:"hover and county name "

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Let's make a map of US-counties with D3.js:"hover and county name "

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Last edited Dec 1, 2020

Created on Dec 1, 2020

This example displays a choropleth-style map of all US counties rendered as SVG paths, with county names revealed on hover via a native `<title>` element. The visualization uses D3 v5’s `geoAlbersUsa` projection and `geoPath` to draw county boundaries from TopoJSON data loaded from the us-atlas package. County shapes are styled with black strokes and a green fill on mouseover, showing the geographic distribution of administrative divisions. The code filters the TopoJSON for county features and binds them to path elements, relying on the browser’s built-in tooltip behavior for the name display.

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