d3 Choropleth Map

Massachusetts Chrolopleth map with interactive legend and viewbox

This choropleth map displays Massachusetts town boundaries colored by county, with an interactive legend that highlights matching regions on hover. The visualization uses React with D3 v5 APIs including `geoAlbers`, `geoPath`, and `scaleOrdinal` to project and render the TopoJSON geometries. A viewBox crops the map to the state, while legend hover states adjust fill opacity for focused counties. Town-to-county mappings come from a CSV gist, and geographic data originates from MassGIS shapefiles converted through ogr2ogr and mapshaper.

Mass Map Chrolopleth map

This example displays a choropleth map of Massachusetts, with each county rendered as a purple SVG path. The map uses a custom `d3.geoAlbers` projection, centered and rotated to focus on the state, with a high scale factor for magnification. County boundaries are drawn from TopoJSON data using `d3.geoPath` and `topojson.feature`. The visualization is built with React, which loads the geographic data asynchronously and passes it to SVG path elements.

Massachussets

This example visualizes Massachusetts school districts as a choropleth map, with each town randomly assigned one of three colors from a categorical scale. The geographic boundaries are rendered using a conic conformal projection through `d3.geoPath`, while React manages the component structure. Data is loaded from a local TopoJSON file containing town boundaries, and the color mapping is applied via `d3.scaleLinear`. The map is displayed as SVG paths with black strokes highlighting district borders.

11993-INDALKAR

Massachusetts Towns

This example visualizes the towns of Massachusetts as a choropleth-style map using SVG. It loads GeoJSON town boundaries from a remote gist and renders them as filled paths with black strokes via `d3.geoPath`, projected using `d3.geoConicConformal` with parameters fit to the state. The map is drawn into a dynamically created SVG element sized 800×400, with the projection fitted to the data extent. D3 v5 and TopoJSON are used for data loading and path generation, though the code appears incomplete as only the town polygons are shown without additional styling or interactivity.

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Massachusetts Chrolopleth map with interactive legend

This interactive choropleth map of Massachusetts displays county boundaries, with each town colored according to its county. A legend on the right uses an ordinal color scale and responds to mouse hover, dimming non-matching map regions and highlighting the selected county. Built with React and D3 v5, it uses `d3.geoAlbers` and `d3.geoPath` to project and render TopoJSON features converted from Massachusetts town boundary shapefiles via mapshaper. County assignments come from a CSV mapping file, and the legend uses `d3.scaleOrdinal` for color encoding.

Mass Map 2

This example renders a choropleth map of Massachusetts using the Albers equal-area conic projection. It displays the state’s geographic boundaries as SVG paths, colored with a teal stroke and fill. The visualization uses React to manage state and rendering, calling `d3.geoPath` with `d3.geoAlbers` to project the GeoJSON data fetched from a GitHub gist via `d3.json`. The `topojson` library’s `feature` function converts the TopoJSON structure into GeoJSON features for plotting.

Massachusetts Chrolopleth map with interactive legend

This choropleth map shows Massachusetts town boundaries colored by county, with an interactive legend that highlights matching regions on hover. The visualization uses React with d3.v5, including `d3.geoAlbers` for projection and `d3.geoPath` for rendering SVG paths from TopoJSON data. A CSV file maps towns to counties, and the legend employs `d3.scaleOrdinal` with a custom `ColorLegend` component. Hovering a legend value dims non-matching towns via reduced opacity while brightening the selected county.

85% match

Massachusetts Chrolopleth map

This choropleth map displays the counties of Massachusetts, with each town colored according to its assigned county via a categorical color scale. A conic conformal projection (d3.geoConicConformal) is used to render the state’s boundaries, while d3.geoPath draws the polygons from a TopoJSON source. Town-to-county mappings are loaded from a CSV file, and the color scale is a d3.scaleOrdinal. The visualization is built with React, using d3.v5 for geographic and data processing, and outputs as SVG paths.