Gott-Goldberg-Vanderbei may have a lower error, but its usefulness is also significantly reduced.

My favourite for world maps is still Winkel Tripel (https://en.wikipedia.org/wiki/Winkel_tripel_projection). Winkel-Tripel was given one of the best ranks by Gott and Goldberg, before they developed the projection in the OP.

Winkel Tripel used to be the standard until Google Maps came along and pushed everyone back to using Mercator for data visualization and political maps.

If we're doing strangely discontinuous maps, I'd like to submit Fuller's Dymaxion Map [1] -- at least that one keeps the continents contiguous, while truly minimizing deformations.

1: https://en.wikipedia.org/wiki/Dymaxion_map

Their justification for no boundary cut error is kinda dodgy.. they say they have none because this projection is really two discs back to back, 'you can just stretch a string over the edge of the disk'.

That's cool but by that argument can't i just fold a Mercator map in half and also have no boundary cut?

I've seen maps of the heavens using this projection, with the added stipulation of the celestial equator being on a separate bar. So the two circles would represent e.g. +45 degrees north and south of the celestial equator, and the bars would represent from 45 north to 45 south (or thereabout, I'm not sure about the actual degrees).

Here's one that I just found online:

https://fineartamerica.com/featured/vintage-stars-map-celest...

if you click the map - just West of the tip of India- it creates a much better division - without slicing populated continents in half

Is there any reason why the rotation animation doesn't just use CSS rotation? The code looks rather complicated and this old laptop seems to really be unhappy to do what appears to just be two images doing a standard rotation.

Is it not that?

This map we made does the best in this metric we invented!

Am I understanding correctly that this is just two 'azimuthal equidistant projections' center on antipodal points, side by side?

(but envisioned as being glued to opposite sides of a single disk)

For the OP projection, the best centre seems to be around the Isle of Man. Edit: Just north of Cornwall gets most of the land except SEA, southern tip of South America and Australia+Antarctica.

I just like properly split sinusoidal map the most though [0] Sinusoidal map is where you start at the pole and unwrap the circles of latitude.

[0] https://en.wikipedia.org/wiki/File:Usgs_map_sinousidal_equal...

But, for what definition of "error"?

The problem with map projections in the digital age is what works well on world scale doesn't on street scale and vice versa. As explained in detail in this post: https://www.mapbox.com/blog/adaptive-projections

Here’s the D3 implementation (which is just an interrupted azimuthal equidistant projection):

https://observablehq.com/@d3/azimuthal-equidistant-hemispher...

Hilarious to cut Africa in half and present it as errorless

At that point, just render a globe.

Why does the HN title have a false editorialized claim that is not in the linked page?

Map projections are fun but have limited relevance in the age of computers. Almost all on-screen interactive maps should use perspective projection, the only intuitive projection. (I feel like people dismiss perspective projection as not a "real" map projection, but it most definitely is.) If you need to judge relative sizes or distances or draw straight lines or whatever other things you might want from a map projection, software tools can help you do it more easily and more accurately.

It's difficult to visually distinguish GGV from the good ol' Mollweide Hemispheres projection (https://www.jasondavies.com/maps/mollweide-hemispheres/). As an added benefit, Mollweide projections are equal-area.

Having the boundary at the equator is a strange choice. If you instead have the boundary go through the poles and the cook strait (e.g. click roughly at the edge of the northern hemisphere ~45 degrees down and left on the interactive map), then you end up only cutting off the Russian Far East and Antarctica, all other major landmasses are preserved.

'of land'. For less-accurate needs I prefer the ones that still show (roughly North-top, South-bottom and) lat/long lines and non-blue space where water is separated by the mapping.

Maybe this mapping is most useful for accurately tracking global warming effects at the poles.

I made an interactive WebGL implementation of this without realizing it was a thing: https://brian.sh/around/index.html

I don't really agree with the claims in the articles linked in OP, and don't find it to be a generally useful projection, even for the tool I made using it. It was novel as a representation that included daylight context (instead of just "what time is it there?" it helped express "is it getting dark there?") that preserved area better than a globe and was more intuitive than a day/night waveform on a rectilinear projection. But ultimately, if you're showing anything that has to do with populations (cities, people) pretty much any projection will waste large amounts of space on oceans and unpopulated land regions. That is to say, before choosing a favorite map projection, I think it's probably better to not to use a map projection at all unless you're going for a hike or setting sail.

Somebody beat me to the obligatory xkcd, but this West Wing bit is my go-to for map projection discussions: https://youtu.be/vVX-PrBRtTY

I like framing map projections by what they prioritize or sacrifice—fidelity in axis, position, size—and what projection is "best" depends entirely on which characteristics are more important. I disagree with OP's claim about this projection being "the most accurate flat map of the Earth yet" though haven't put a ton of thought into the physical, back-to-back definition of "flat" vs on-screen.

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