Unusual map projections like these are often curiosities, but the can also be useful for certain topics, like mapping migrations[1][2][3] or showing airline rou

Unusual map projections like these are often curiosities, but the can also be useful for certain topics, like mapping migrations[1][2][3] or showing airline routes[4][5]. [1]: https://commons.wikimedia.org/wiki/File:Map-of-human-migrations.jpg https://commons.wikimedia.org/wiki/File:Map-of-human-migrati... [2]: https://nordpil.com/static/images/redknot_migration.png https://nordpil.com/static/images/redknot_migration.png [3]: http://ngm.nationalgeographic.com/ngm/0603/feature2/map.html http://ngm.nationalgeographic.com/ngm/0603/feature2/map.html [4]: https://imgur.com/5TFPcDa https://imgur.com/5TFPcDa [5]: https://imgur.com/6X91323 https://imgur.com/6X91323 Additionally, this project is a generalization of a feature that already existed in D3 (clipping spherical polygons to map boundaries -- previously you could only do this if the boundary in question was the antimeridian or a small circle centered at the origin). That generalization will make it easier to use some more common map projections that were already supported in d3-geo-projection[5] like as Goode's interrupted homolosine and Mollweide projections. These are useful projections for showing things like population density[6] where you care about preventing distortion in the landmasses but don't care about the oceans. While these projections were possible before, they required the use of SVG clip-paths and other tricks to prevent drawing outside the map bounds. In theory they could now be simplified using the polygon clipping implemented in d3-geo-polygon. [5]: https://github.com/d3/d3-geo-projection https://github.com/d3/d3-geo-projection [6]: http://www.jakelow.com/essays/mapping-the-world-population http://www.jakelow.com/essays/mapping-the-world-population