this post was submitted on 13 Mar 2025
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[–] Suck_on_my_Presence@lemmy.world 10 points 1 day ago (2 children)

I think I'm too stupid to understand this. How are they straight lines and not at a diameter / in a circle from any given point? It seems... wrong.

[–] Ephera@lemmy.ml 34 points 1 day ago* (last edited 1 day ago) (2 children)

Oh! It totally does. I guess I've just never had to apply distances in such a way that they'd butt up against one another to become what looks like basic geometry.

Thanks!

[–] Successful_Try543@feddit.org 4 points 1 day ago* (last edited 1 day ago)

I assume part of the confusuion is that the earth is not flat. If one would create a Voronoi diagram on the surface of a globe, the resulting borders would still be straight lines, but, when projected, it depends on the projection, whether they remain straight.

The creator probably started with a Mercator projected map of Europe and then calculated the distance between any point on the map and all capitals. The distance on two points on the spere, however, cannot be obtained by counting the distance in h/v pixels on the map and applying Pythagoras, as Mercator projection exaggerates horizontal, east-west, distances. So one needs to map the pixel coordinates back onto the sphere and calculate the distances there.

It's definitely a nice map though.

[–] Kusimulkku@lemm.ee 4 points 1 day ago (1 children)

What does the separating line between two circles look like?

[–] FreeRangeMustard@lemm.ee 5 points 1 day ago (2 children)
[–] Kusimulkku@lemm.ee 13 points 1 day ago* (last edited 1 day ago) (1 children)

I've tried to demonstrate it here. You end up with straight lines because it's always a middle point so it doesn't curve one way or another between the two points.

If the circles had a set radius then you'd have empty space and more circley-looking spots. But since they basically expand until there's a middle point you'll have these straight lines.

[–] FreeRangeMustard@lemm.ee 7 points 1 day ago (1 children)

I was joking. But +1 for the effort and this looks like art, btw.

[–] Kusimulkku@lemm.ee 6 points 1 day ago

Oh dang didn't realize you weren't the same person. Thanks for the compliment, I had fun drawing it

[–] Kusimulkku@lemm.ee 3 points 1 day ago

Draw it, then consider where the exact middle point would be. Now do the whole line between them. I think that's the best way to figure it out.