Equal Earth Web Mapping

Equal-area projection for web mapping

Most of today's web maps are using the Web Mercator projection. A major issue of Web Mercator is the distortion of area sizes far from the equator.

In 2018 Bojan Šavrič, Tom Patterson and Bernhard Jenny published their work on the Equal Earth map projection, an equal-area projection for world maps.

This site is an information collection about using the Equal Earth map projection for web mapping.

Equal Earth vector tiles using Web Mercator grid

A quadratic grid for Equal Earth centered on Greenwich is similar to a Web Mercator grid. Instead of Mercator grid corners at (-20'037'508, 20'037'508) and (20'037'508, -20'037'508) the grid corners of Equal Earth Greenwich are at (-17'243'959, 17'243'959) and (17'243'959, -17'243'959).

Tiles produced in Equal Earth projection on a Equal Earth Greenwich grid can be adressed with the same tile numbers by a map viewer using a Web Merctor grid. Tiles are displayed with a scale factor of 1.162. Conversions between geographic WGS84 coordinates and the map coordinate reference system give wrong results without adapted calculations. But maps can be displayed without any coordinate projection calculations.

Basic usage examples:

• MapLibre | Asia-Pacific centered | Americas centered
• OpenLayers | Asia-Pacific centered | Americas centered
• OpenLayers switching to Web Mercator
• Leaflet
• DeckGL

Combined Equal Earth / Web Mercator vector tiles

Examples:

• MapLibre
• OpenLayers
• Leaflet

Equal Earth vector tiles using Equal Earth grid

Examples:

• OpenLayers
• OpenLayers with Proj4js
• OpenLayers with GL JSON style
• OpenLayers with projection switch

Reproject data to Equal Earth

Examples:

• D3 / Observable
• OpenLayers - GeoJSON with mouseover infos
• OpenLayers - OSM raster tiles
• Gleo - styled GeoJSON
• Matplotlib add-on

Creating data in Equal Earth projection

There are official EPSG codes for the following Equal Earth projection variants:

• Equal Earth Greenwich: EPSG:8857
• Equal Earth Americas: EPSG:8858
• Equal Earth Asia-Pacific: EPSG:8859

So most GIS software packages already support working with data in Equal Earth projection.

Example using GDAL:

ogr2ogr ne_10m_populated_places.fgb -t_srs EPSG:8857 /vsicurl/https://github.com/nvkelso/natural-earth-vector/raw/master/geojson/ne_10m_populated_places_simple.geojson

Open Street Map extracts in Equal Earth projection

OSM extracts in Equal Earth projection can be produced with https://osm2pgsql.org/themepark/

A detailed tutorial will follow.

Vector tiles in Equal Earth projection

Vector tiles in Equal Earth projection can be produced with https://www.bbox.earth/tile-server/

A detailed tutorial will follow.

Tile matrix sets:

• Equal Earth Greenwich: EqualEarthGreenwichWGS84Quad.json

Feedback and contributions

For feedback please open an issue or pull request on https://github.com/bbox-services/equal-earth-web-mapping