Skip to main content
SimilarExport ZIP
100%

Let's make a map with D3.js!

✓ Published0🌍 Public
KKonstantin Krumin
Last edited Apr 9, 2020
Created on Apr 9, 2020

This example demonstrates how to create a choropleth map of U.S. counties using D3.js. It renders an SVG projection of the United States with a light background, then overlays county boundaries and merges them with education data loaded from freeCodeCamp’s testable projects API. The code uses `d3.geoAlbersUsa` for the projection, `d3.geoPath` to generate paths, and TopoJSON’s `feature` method to extract county geometries. Education statistics are fetched in parallel with county boundaries via `Promise.all`. The resulting visualization shows county outlines but does not yet color them by data values.

AI-generated description
MIT Licensed

Similar vizzes

Loading thumbnail…

Let's make a map with D3.js!

This example demonstrates how to create a choropleth map of U.S. counties using D3.js and TopoJSON. It renders a geographic projection with the `d3.geoAlbersUsa()` projection and `d3.geoPath()`, drawing landmasses as light green paths over a blue sphere. The map fetches county boundary data from the freeCodeCamp CDN, processes it with TopoJSON’s `feature()` function, and appends each country as an SVG path. The visualization uses an SVG canvas and is accompanied by a video tutorial, showcasing a straightforward workflow for building interactive maps.

KKonstantin Krumin
93% match
Loading thumbnail…

Let's make a map US-counties with D3.js!

This example renders a choropleth-style map of all US counties as light green SVG paths with subtle black borders. It uses D3 v5’s `geoAlbersUsa` projection and `geoPath` generator to convert TopoJSON county boundaries from the `us-atlas` dataset into scalable vector graphics. The code loads the TopoJSON via `d3.json`, extracts features with `topojson.feature`, and binds them to SVG path elements, while styling is handled with CSS class selectors.

NNita
88% match
Loading thumbnail…

Let's make a map with D3.js!

This example shows a basic choropleth map of U.S. counties, rendered as solid maroon SVG paths with thin black borders. The visualization uses D3 v5’s `geoPath` and `geoMercator` to project TopoJSON county boundaries loaded from a FreeCodeCamp-hosted dataset. The map displays all counties at once without any interactivity or data-encoding choropleth coloring, serving primarily as a technical demonstration of projecting and drawing geographic features with D3 and TopoJSON.

Eezzep66
87% match
Loading thumbnail…

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

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.

NNita
86% match
Loading thumbnail…

Let's make a map with D3.js!

This example visualizes U.S. county boundaries as a natural Earth projection map, with the sphere background filled in blue and country shapes rendered in light green. It loads GeoJSON data from a freeCodeCamp choropleth dataset and uses `d3.geoPath` with `d3.geoNaturalEarth1` to project and draw the paths. The code selects an SVG element, appends a sphere path, then joins the TopoJSON features to append individual county paths using D3's data join. The map is static, with no interaction or animation beyond the initial rendering.

Ssriramvsharma
85% match
Loading thumbnail…

fcc-d3-04

A choropleth map of U.S. county education levels, rendered as SVG paths with an Albers USA projection, displays a visual distribution of data across the country. The React app loads county boundary TopoJSON and education statistics via `d3.json`, then uses `d3.geoPath` with `geoAlbersUsa()` to project each county boundary. While the code defines the map’s layout and data fetching, the actual color encoding for each county’s education value is not implemented, leaving the map uncolored. The visualization depends on React state to coordinate asynchronous loading of both datasets before rendering.

SSiddharthMittal07
84% match
Loading thumbnail…

map: usa, counties

This example renders a choropleth-style map of the United States, displaying county and state boundaries overlaid on landmasses, with graticules and a sphere outline. It uses a React component with `d3.geoAlbersUsa` for projection and `d3.geoPath` for drawing geometries. Data comes from the US Atlas TopoJSON (`us-atlas@3.0.0/counties-10m.json`), processed with `topojson.feature` and `topojson.mesh`. Interactive tooltips show county and state names on hover. The SVG output is styled with semi-transparent fills and distinctive boundary strokes.

Zzach b.
84% match
Loading thumbnail…

Let's make a map with D3.js!

This example demonstrates how to create a choropleth-style map of the United States using D3.js, highlighting a subset of states with a distinct CSS class. It loads TopoJSON data from `https://d3js.org/us-10m.v1.json` and uses `d3.geoAlbersUsa` for projection and `d3.geoPath` to render state boundaries as SVG paths. The code filters state features against a predefined set of FIPS IDs, though the visual highlighting of selected states is commented out.

Jjons288
83% match