Important Context: @ratlimit is a satire account.

  • jaybone@lemmy.zip
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    6 hours ago

    The next one will be in the Arctic.

    Also didn’t know we were calling this the UWU shooting.

  • ceenote@lemmy.world
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    11 hours ago

    Guys, I went to the center of the circle, and there was a completely normal looking tree there. Maybe too normal. What could it mean?

    • Natanox@discuss.tchncs.de
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      5 hours ago

      Don’t take all this stuff too seriously, most of it is either performative content revenue farming or manipulation of public opinion by some actor. This ticks all boxes, could be anything; a person honestly that dense or deep into conspiracy theories isn’t even the most likely one. Unfortunately neither is satire.

  • megopie@beehaw.org
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    11 hours ago

    I wonder what size the circle would be if you took in to account the earth’s curvature.

    Are there any map projections that allow for accurate projection of circles across arbitrary points?

        • Successful_Try543@feddit.org
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          4 hours ago

          There are projections where infinitesimal circles stay circles, e.g. our dear Mercator projection, but that doesn’t hold for finite sized circles, i.e. circles would still be distorted in north-south direction.
          Tissot indicatrix

          • redjard@lemmy.dbzer0.com
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            4 hours ago

            That’s a general metric holding for lots of projections. I think the specific projection that works for finite sized circles is stereographic projection.
            On a stereographic map you should be able to draw a circle that stays a perfect circle (“small circle”) on a globe.

            In addition, in its spherical form, the stereographic projection is the only map projection that renders all small circles as circles.

            By small circles they mean circles on a sphere that are not an equator (great circle), not infinitessimally small circles. So basically they just mean circles.

            • Successful_Try543@feddit.org
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              4 hours ago

              By small circles they mean circles on a sphere that are not an equator (great circle), not infinitessimally small circles. So basically they just mean circles.

              This only applies to the circles perpendicular to the axis of projection, i.e. usually the circles of latitude (parallels), though. The Tissot indicatrices still show increasing sizes of the circles from the center of the map to its outside. Thus, any circle that isn’t coaxial with the parallels is distorted on the map.

              • redjard@lemmy.dbzer0.com
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                4 hours ago

                There is no qualifier on wikipedia and I do remember seeing some neat geometry tricks you can do with the property long ago.
                The Tissot thing to me looks like a visualization for the jacobian, so the factor by which the area at that point is scaled, plus the gradient.
                The circles in the stereographic projection are scaled, they are essentially pulled outwards, when further away from the center. This matches an increasing jacobian. But they stay circular, the stretching happens in the right way for that to hold true.

                If you wait a bit I’ll see if I can find some further things relying on this property, or at least stating it more unambiguously.

                • Successful_Try543@feddit.org
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                  2 hours ago

                  The Tissot thing to me looks like a visualization for the jacobian, so the factor by which the area at that point is scaled, plus the gradient.

                  Essentially, the tissot indicatrices are a visualization of the eigenvalues and eigenvectors of the projection in any point. So, in 2d, the areas of these ellipses correspond to the Jacobi determinant, the product of the two eigenvalues of the Jacobian at that point.

                  The circles in the stereographic projection are scaled, they are essentially pulled outwards, when further away from the center. This matches an increasing jacobian.

                  Exactly. The Jacobi determinant increases in radial direction (longitudinal on the globe).

                  But they stay circular, the stretching happens in the right way for that to hold true.

                  If you draw a circle on a globe, that is not coaxial to the parallels and apply the projection, the radius of said circle becomes elongated in outward direction in the same way the circles of the Tissot indicatrices increase in size.

                  Or in other words, any slice oncrement of the circle along a fixed degree of latitude changes in size depending on the value of the Jacobi determinant at that degree of latitude.

                  Thus, the circle on the globe becomes somehow like a rounded triangle on the map.

                  Edit: That shifts only the center of the mapped circle towards the outside of the original, but the circle remains a circle.

    • Eq0@literature.cafe
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      9 hours ago

      If you drew in on a globe, it would look deformed in this projection. I think the radius wouldn’t change, but it would look “wider” towards the north

  • _stranger_@lemmy.world
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    9 hours ago

    The center of that circle is the Northwest Angle, and it’s populated by turmpers. It was created by a “survey error”. This tells me that Canada killed JFK because they knew Turmp would happen if they did. This was a Canadian attack all along.

  • omgboom@lemmy.dbzer0.com
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    11 hours ago

    I got in trouble in my friend group meme chat for drawing a Star of David connecting the points in this meme

    • 0ops@piefed.zip
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      9 hours ago

      That’s almost the plot of the rdj Sherlock Holmes movie. Just, you know, different star.

  • hactar42@lemmy.ml
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    11 hours ago

    We’ll just forget about William McKinley because Buffalo doesn’t fit into our perfect circle

    • takeda@lemmy.dbzer0.com
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      10 hours ago

      If he did, he wouldn’t be able to use circumcircle theorem.

      What’s crazy is that this does fool people despite them drawing circles many times around triangles in their math class.

      Wasn’t that in elementary or middle school?