Custom Cartesian Projection

Custom Projection

This example displays a map of California counties and their boundaries, rendered with a custom 2D affine transform instead of a standard geographic projection. The `d3.geoPath` and `d3.geoTransform` APIs apply a matrix operation that flips the y-axis, allowing pre-projected TopoJSON data to be correctly positioned within the SVG viewport. The map uses gray fills and strokes, with counties and boundary lines drawn as separate SVG paths.

80% match

Rectangular Polyconic

This example demonstrates the rectangular polyconic map projection, a pseudoconical projection that renders the world with curved meridians and straight parallels. The map shows landmasses in dark gray with country boundaries in white, overlaid on a graticule grid and enclosed by a spherical outline. Built with D3.js v3, it uses `d3.geo.rectangularPolyconic` from the extended projections plugin, `d3.geo.path` for geographic rendering, and `d3.geo.graticule` to generate the grid. World geometry comes from a TopoJSON file loaded via `topojson.feature` and `topojson.mesh`.

79% match

Polyconic

This visualization demonstrates the Polyconic map projection, a compromise projection that preserves distances along the central meridian and each parallel. It displays the world’s landmasses as solid black shapes with white country boundaries, overlaid on a graticule grid and an outlined sphere. The example uses the D3 v3 library with the `d3.geo.polyconic` projection plugin, `d3.geo.path` for rendering, and `topojson.v1` to process world-50m.json geographic data, drawing everything as SVG paths.

Transverse Mercator

This example demonstrates the transverse Mercator map projection, displaying world landmasses and country boundaries within a graticule grid. The map is rendered as SVG using the D3.js library, specifically employing the `d3.geoTransverseMercator` projection and `d3.geoPath` for drawing geometries. World data comes from the `world-atlas` package, processed with `topojson-client` to extract land and boundary features. The visualization includes a spherical outline, a graticule, and styled land and boundary paths, all centered within a 960x960 canvas.

Stretched Projection

A custom D3 v3 geo projection stretches the equirectangular world map to fill a 960×500 viewport. The code defines a cylindrical projection function using `d3.geo.projection` to scale latitude coordinates proportionally to the viewport’s aspect ratio, then renders land and country borders with `d3.geo.path` and TopoJSON data. SVG paths display the stretched map with gray land and white country boundaries.

Satellite Projection

This example shows a satellite projection of the United States, with a graticule overlay and land boundaries rendered as SVG paths. The projection is created with `d3.geo.satellite()`, configured with a distance, scale, rotation, center, and tilt to simulate a view from space. The graticule is generated using `d3.geo.graticule()` and the map data is loaded from an external JSON file via `d3.json`. The code uses `d3.geo.path()` with the projection to draw both the graticule and the land polygons, which are converted from TopoJSON using `topojson.feature()`.

Flat-Polar Parabolic

A flat-polar parabolic projection maps the world onto an oval-shaped canvas, with landmasses filled in dark gray and country boundaries marked by thin white lines. The visualization also includes a graticule grid and an outer sphere outline, rendered as SVG paths using d3.geo.path and the d3.geo.mtFlatPolarParabolic projection. Geographic data comes from a TopoJSON world file, processed via topojson.feature and topojson.mesh. The projection scale and translation are set explicitly, with precision configured for smooth rendering.

77% match

August Projection

This example displays a world map using the August projection, a pseudocylindrical equal-area projection that curves parallels and meridians into distinctive intertwined shapes. The map renders land masses in dark gray with white country boundaries overlaid on a graticule, all enclosed within a spherical outline. Using D3 v3, the code employs `d3.geo.august` for the projection, `d3.geo.path` to draw geographic features, and `d3.geo.graticule` for the grid. TopoJSON data provides the world land and country boundaries, loaded from an external JSON file.