🧵 1/2: I recently saw this vintage #Qantas poster with a unique “flower” map projection centered on #Sydney (1st image).
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🧵 1/2: I recently saw this vintage #Qantas poster with a unique “flower” map projection centered on #Sydney (1st image). I like how the map almost neatly divides the four largest continents (Eurasia, North America, South America, and Africa) into the four petals.
Well, I kinda became obsessed and wondered if I can recreate it using the mapmaking skill I have.
After some tinkering and mathing I think I was able to do it! (2nd image)
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🧵 1/2: I recently saw this vintage #Qantas poster with a unique “flower” map projection centered on #Sydney (1st image). I like how the map almost neatly divides the four largest continents (Eurasia, North America, South America, and Africa) into the four petals.
Well, I kinda became obsessed and wondered if I can recreate it using the mapmaking skill I have.
After some tinkering and mathing I think I was able to do it! (2nd image)
️🧵 2/2: I have no idea what this floral projection is or if it even has a name. I haven’t seen this in any list of map projections. The closest I know is the Gingery projection which is also aviation related:
https://www.jasondavies.com/maps/gingery/ (by @jasondavies)
Normally, an azimuthal equidistant map is used to show great circle distances from a central point. But because shapes are greatly distorted the farther from the center you go, an interrupted projection like Qantas’s or the Gingery could be used.
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🧵 2/2: I have no idea what this floral projection is or if it even has a name. I haven’t seen this in any list of map projections. The closest I know is the Gingery projection which is also aviation related:
https://www.jasondavies.com/maps/gingery/ (by @jasondavies)
Normally, an azimuthal equidistant map is used to show great circle distances from a central point. But because shapes are greatly distorted the farther from the center you go, an interrupted projection like Qantas’s or the Gingery could be used.
@seav Wait, is this *both* equidistant (from the center) *and* equal-area?
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🧵 1/2: I recently saw this vintage #Qantas poster with a unique “flower” map projection centered on #Sydney (1st image). I like how the map almost neatly divides the four largest continents (Eurasia, North America, South America, and Africa) into the four petals.
Well, I kinda became obsessed and wondered if I can recreate it using the mapmaking skill I have.
After some tinkering and mathing I think I was able to do it! (2nd image)
️@seav This reminds me of our current atlas in the geography department in school.
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@seav Wait, is this *both* equidistant (from the center) *and* equal-area?
@IvanSanchez I can’t prove it, but I’m not sure this is equal-area. But if my calculus intuition is correct (infinitesimal slices), it might be!
Also, except for the exact spines of the “petals”, I don’t think this is really equidistant since the radial great circles curve away from the petal spines.
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J jwcph@helvede.net shared this topic
