1y ago

Side-effect of flattening a globe

119 comments

Mercator Projection. So many ways to try to represent a sphere on a flat 2D plane but none are perfect
https://theconversation.com/five-maps-that-will-change-how-you-see-the-world-74967
And this “True Size” map is fun to play with.
TheTrueSize
- Dymaxion map for life!!
  
  What Your Favorite Map Projection Says About You
  Dymaxian
  You like Isaac Asimov, XML, and shoes with toes. You think the Segway got a bad rap. You own 3D goggles, which you use to view rotating models of better 3D goggles. You type in Dvorak.
- What Greenland actually looks like is always wild.
  It looks like this massive arrow head that stretches so far to the east and west as you go north...
  When really it's just like a normal island.
  
  And japans larger than it seems too when compared to the eastern US.
  Or the sheer size of the African continent
  
  Still pretty big though, about the same north-south as the u.s.
- Damn I didn't realise New Zealand is a fair bit larger than the UK, but only has like 7% of the population. Damn, that place must be empty.
  Japan is also surprisingly huge. I always assumed Japan and the UK were similar in size, it's like 1.6x the size, jesus.
  Maps be crazy.
- It's a bummer this article pushes aside the importance of calculating bearings. Figuring bearings remains a required skill in both sea and air navigation. GPS works very well, but you don't want to depend entirely upon it when there's life and property at risk. Sextants, chronographs, and navigational maps remain onboard many ships.
  To not be so negative, here's something interesting the article does raise but didn't mention: azimuthal maps are regularly projected at any place on earth. Azimithual projected at a radio station this makes pointing directional antennas intuitive and fast. It's also helpful in grasping how a directional antenna will behave as their radiation patterns are drawn in polar coordinates and hence can be drawn on top of an azimithual map.
- It's possible to project a sphere perfectly onto flat 2d space if you just take one single point out. You just need an infinitely big plane

Another thing we mostly have no clue about thanks to most of our maps is how massively large the Pacific ocean is.
- And somehow fellas just sort of wandered to places like pitcairn islands, chance of a million.
  Pitcairn islands are a great wikipedia rabbit hole if you're into freaky crazy shit btw.
  
  There's a whole season of the podcast Extremities about Pitcairn. Totally worth it.
  
  What a wild read. Thanks for sharing
  
  The band Rasputina does a good bit about the Pitcairn Islands.
  https://en.wikipedia.org/wiki/Oh_Perilous_World
  
  Ended up watching this awesome indie documentary about it: https://m.youtube.com/watch?v=Gr7MWxADnko
- Can confirm, I lived in the middle of it (Polynesia), first airports (Auckland and LA) were 6 and 8h flights away.
  
  What is it like over there? How's foods and all?
  
  first airports (Auckland and LA) were 6 and 8h flights away
  It must have been a real pain in the ass catching those flights without an airport. Did people get shot out of a cannon and hope to grab onto the wing? Did their baggage also get cannoned?
- pirate island birds tweets in the background
- If you would push all the landmasses together, they would still be smaller than the Pacific ocean.
- Or that the shortest route to China is over Siberia.
  
  Or that the shortest route to China is over Siberia.
  That depends entirely on where you start.

Maybe the kms in Asia are larger than the ones in Africa. Since the metre is defined as the distance traveled by light in 1/299792458s, one can only conclude that light is slower in Asia. Because it's cold. It makes sense. Light is cold-blooded, maybe? See my next paper in Nature, idk.
- this can't be right. i have it on good authority that every 60 seconds in africa, a minute passes. and since time is space...
  
  I think you'll also find that the rains in Africa are blessed, so it's reasonable to assume that these residual divine energies could warp spacetime.
  
  Together, we can stop this.
  
  every 60 seconds … a minute passes
  wtf lol check it out this idiot lmao
- Let's see the colder it is the more dense the air is. As we all know the speed of light is measured in a vacuum and the more dense the medium light moves through the slow it gets. So this check out. Just don't drive from Dallol to Yakutsk, your speedometer is going to be way off.

Isn't there a flat map where the actual scale is kept intact? That fucker looks so weird when you've been taught the other one your whole life. It's like planetary dysmorphia.
- https://thetruesize.com/
  
  Fascinating, thanks for sharing!
  Australia and China are absolutely massive, wow. They look deceptively small on most maps 🤯
  
  That's a cool site, thank you for sharing it!
- Effectively no. Any projection of a spherical surface into 2D will distort it in some way. If I understand correctly, the Mercator projection (which I think is what we're looking at) is a cylindrical projection, which preserves latitude but severely distorts longitude near the poles.
  I do know that aeronautical charts are conical projections, which is fairly distortion free for the relatively small area they cover, but you can't lay more than a few of them edge to edge before things stop lining up.
  
  You have distort some thing. Scale or directions. The one most people use keeps directions constant. Ie a 45 degree line between North and east will akways point due northeast no matter where it is.
  Contrast that with a map that cuts out large triangle sections or naos that have tge equator wider then poles. These maps make true northeast variable.
- No, it's not possible to take a 3D surface and to transpose it onto a 2D plane without any distortion.
  
  This is true. There are some projections that show area more accurately, or shape of landmasses, etc.
  For example:
  Dymaxion (less distortion)
  Authagraph (approximately equal area)
  Many map projections do one thing well at the cost of sacrificing others. For example, the popular Mercator projection (which you'll see in many US schools and textbooks) is well suited for marine navigation but is exceptionally distorted the closer you get to the poles.
  
  You can easily do it without distortion. The issue is continuity. You'd have to make cuts and effectively unwraped the globe like you would a 3D sphere. Some countries might literally be cut in half, but it would at least be accurate
  
  Or without chopping it up in an odd way rather than a rectangle.
  
  My fucking..
  UV MAPS
  AGGGGGHHHHH
- There are many different world maps, and some have an intact scale. But they lack in other ways.
  Map Men has a good video about it:
  https://piped.video/watch?v=jtBV3GgQLg8
- No, but there are several better projections. The Mercator is a nautical chart, it was never intended to be used as a general purpose map of the world but for some reason it's used that way.

Actually this is a bit misleading. If you check google maps you can see that those straight lines are not the shortest path between those points. Also, that's not the longest distance between 2 points in Russia.

The point still stands that these two distances are practically the same when they appear vastly different in a 2D projectio.
Edit: I might have placed the marker in Crimea. Sorry about that. The point still basically stands.
- This may be off topic, but it's sadly not a common occurence to see someone correct something "a bit misleading", while acknowledging that the point is still valid.
  You are cool. Keep being you.
  
  I mean this map/number is just straight up wrong. There might be a point about Mercator projections distorting apparent size away from the equator but in reality the line across Russia is well over 8000 km long not 6400 km.
- You have made a political statement about crimea, watch out for Russia simps
  
  Oof. I though I stopped just short of Crimea?
- Actually this is a bit misleading.
  I think thats the the entire point of this post is how the projection is misleading lol
  
  Yes but in trying to show how the projection is misleading, the post is still misleading you... Meaning the original was less misleading than you were made believe. By committing the same error caused by the projection itself. The post is trying to show that Africa is wider than Russia but it's not.
- How long from Kaliningrad?
  
  Why would we measure from Královec?

I'm still annoyed that the default in Google Maps isn't a spherical mapping. You can set it to use a sphere if you're logged in, but that's not the default.
In the past, the only reason for a flat map was paper, but since it's now easy to project a 3d image on a 2d screen, there's no reason that online maps should ever use anything other than a sphere. Yet, Mercator is the default for Google Maps, which just confuses another generation of kids.
- So many projections to chose from and none of them are perfect. Except the sphere
  
  And since we don't have holographic displays, the sphere has some issues too. Still, it should be the default for anything computer-based.

I wonder if there would be any way to try to quantify the cost of mistakes made by the simple impossibility of accurately projecting a round image onto a flat surface.
You know, people make dumb mistakes because they just forget a conversion or something. People also probably make dumb mistakes because they forget to mentally correct a Mercator projection.
- I feel like there's lots of soft mistakes, for example one might underestimate the size of African countries and therefore underestimate just how atrocious the colonization era was.
- People also probably make dumb mistakes because they forget to mentally correct a Mercator projection.
  A Peters-projection proponent then?
  
  Really, I just love globes. Had one as a kid. Also had a sailing game where you sailed around the world being a pirate, engaging in trade, exploring etc. The globe made the game a lot easier, could like, look back and forth from the globe to your screen to figure out where you were, since you already roughly knew. Played the shit out of that game, probably would've platinumed it if steam achievements were a thing.
  Anyways though, the two together formed my brain in a way that any projections just kinda make it hurt a little. Mercators are the worst, of course. But in my head, they're all supposed to look how they look on a globe.
- Idk, I think we’ve all seen a 3D model of a globe enough times to not be that surprised by this
  
  We've all done unit conversions too. But that doesn't prevent occasional errors.

Thsi reminds me of this site where you can overlay the borders of any country anywhere on earth and see how it compares. https://www.thetruesize.com/
- Came here to say this

Greenland may look as big as all of Africa, but it's actually as big as Greenland.
- Every 60 seconds a minute passes in Greenland.
  
  I thought that was the case in Africa.
- Hommes Cartes?
  
  Oui, c'est exactement auquel j'ai fait la référence

Let me just put my two cents in for the Dymaxion Projection. It preserves size and shape, and it also shows how connected the land masses really are.
https://en.m.wikipedia.org/wiki/Dymaxion_map

Every time I look at a real globe it always fucks with my head. Especially when I see just how massive Africa is.

The Mercator Projection strikes again... How big is Greenland?
- It's essentially a 2 bedroom apartment.
  
  And probably costs about the same!
- The populated parts can fit inside about six Manhattan blocks.

- heres a globe you can play with
  
  Wow, that's super cool.
  Weird to have non-spherical projections as an option though. Wind abruptly ceases at some random boundary and picks up again at some disconnected part of the map.