[HN Gopher] Map Projection Transitions
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       Map Projection Transitions
        
       Author : walterbell
       Score  : 174 points
       Date   : 2022-06-20 10:59 UTC (1 days ago)
        
 (HTM) web link (www.jasondavies.com)
 (TXT) w3m dump (www.jasondavies.com)
        
       | troxy1 wrote:
       | To the OP, using chrome when I pause the rotation, then just
       | arrow down through the projections viewing them one at a time,
       | going from mercator to miller causes a weird X shape.
       | https://ibb.co/sWrgtZC
        
         | techbio wrote:
         | Can confirm (but in Firefox), additionally, going back from
         | Mercator to Loximuthal causes an odd inverted bowl-shaped
         | border.
        
       | julienchastang wrote:
       | @jasondavies, Nice work! Would it be possible to have "Distances
       | from North Korea ", but for any point on Earth? In other words
       | "Distances from X" Thanks.
        
       | oidar wrote:
       | Beautiful. I would love to see the Authagraph projection on this.
        
       | chinchilla2020 wrote:
       | What a great graphic. I can't imagine the battle it took to make
       | this work.
        
       | karxxm wrote:
       | It would be very awesome if one could fold and unfold a sphere in
       | order to have a even better intuition how the projections work.
       | For example check this visualization:
       | https://www.youtube.com/watch?v=b1xXTi1nFCo
        
       | cpcallen wrote:
       | This is cool but it's annoying that the poles keep drifting.
       | Sure: let me drag the map in any direction. But it should start
       | with north at the top (and, for most projections, parallel
       | straight lines of latitude) until I move it, and if I put it back
       | there it should stay.
        
         | jacobolus wrote:
         | Here you go: https://observablehq.com/@jrus/projection-
         | transitions-nodrif...
        
       | seltzered_ wrote:
       | To the author: This is really cool and something I've dreamed of.
       | Have you considered adding support for the 'dymaxion map' (aka
       | Airocean World) projection by Buckminster Fuller (
       | https://en.wikipedia.org/wiki/Dymaxion_map )? Or the Waterman
       | Butterfly (
       | https://en.wikipedia.org/wiki/Waterman_butterfly_projection ) ?
       | What kind of challenges are there in implementing transitions to
       | those types of projections?
        
         | jasondavies wrote:
         | Thanks. Interpolating between map projections that have the
         | same clip region is relatively straightforward. When projecting
         | geometries from the surface of a sphere to a 2D plane, you're
         | always going to have a discontinuity somewhere on the sphere,
         | i.e. the clip region. The projections supported so far all have
         | the same discontinuity along the antimeridian (the meridian at
         | longitude +-180deg).
         | 
         | Extending the interpolation to work for projections with
         | different clip regions should be feasible but there are several
         | ways to interpolate between arbitrary shapes in 2D, so I'd have
         | to give it some thought.
         | 
         | Another way to transition between "polyhedral" projections like
         | the Dymaxion map and the Waterman butterfly is to fold and
         | unfold the maps in 3D to and from a closed polyhedral globe.
        
           | Perceval wrote:
           | Really love your previous work on ocean-centered maps like
           | the Spilhaus. Keep up the good work.
        
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       (page generated 2022-06-21 23:01 UTC)