Show HN: Interactively explore different map projections

#1

Post by mjmdavis » Fri, May 19, 2017, 3:50 PM UTC

Show HN: Interactively explore different map projections
mjmdavis.com

Re: Show HN: Interactively explore different map projections

#2

Post by joern » Fri, May 19, 2017, 4:27 PM UTC

nice, one of the best, interactive visualizations of the problems of mercator maps i've seen

Re: Show HN: Interactively explore different map projections

#3

Post by m1el » Fri, May 19, 2017, 5:55 PM UTC

There's a few map projections I really like that don't have most of these problems: HELAPIx[0] and Dymaxion map[1].

HELAPIx is designed to have pixels of the same area, and Dymaxion is designed to have the least distortion.

[0]: http://healpix.jpl.nasa.gov/

[1]: https://en.wikipedia.org/wiki/Dymaxion_map

Re: Show HN: Interactively explore different map projections

#4

Post by mjmdavis » Fri, May 19, 2017, 6:15 PM UTC

m1el wrote: post #3

There's a few map projections I really like that don't have most of these problems: HELAPIx[0] and Dymaxion map[1]. HELAPIx is designed to have pixels of the same area, and Dymaxion is designed to have the least distortion. [0]: http://healpix.jpl.nasa.gov/ [1]: https://en.wikipedia.org/wiki/Dymaxion_map

I think Healpix is included in the tool at the bottom. Also check out the last few in the list which are similar to Dymaxion.

Re: Show HN: Interactively explore different map projections

#5

Post by desdiv » Fri, May 19, 2017, 6:53 PM UTC

Are there any online maps that aren't Web Mercator? Google Maps, Here.com, OpenStreetMap, Bing Maps, MapQuest are all Mercator-only, with no easy option to switch.

Re: Show HN: Interactively explore different map projections

#6

Post by mjmdavis » Fri, May 19, 2017, 7:52 PM UTC

desdiv wrote: post #5

Are there any online maps that aren't Web Mercator? Google Maps, Here.com, OpenStreetMap, Bing Maps, MapQuest are all Mercator-only, with no easy option to switch.

One of the main reasons it's so popular is that is preserves shape, angle and north is always up. This means you can create a tiling map server and use the same tiles at all scales.

Re: Show HN: Interactively explore different map projections

#7

Post by TremendousJudge » Fri, May 19, 2017, 8:15 PM UTC

typo:

>To remedy the horizontal stretching, the Mercator Projection stretches the globe out in the vertical direction an equal amount to the stretching in the vertical direction.

Re: Show HN: Interactively explore different map projections

#8

Post by 1wheel » Fri, May 19, 2017, 11:37 PM UTC

desdiv wrote: post #5

Are there any online maps that aren't Web Mercator? Google Maps, Here.com, OpenStreetMap, Bing Maps, MapQuest are all Mercator-only, with no easy option to switch.

It is possible, but not trivial:

https://www.vis4.net/blog/posts/no-more-mercator-tiles/ (comments are also informative, particularly Tom MacWright's)

https://mapzen.com/blog/escape-from-mercator/

Re: Show HN: Interactively explore different map projections

#9

Post by MichailP » Sat, May 20, 2017, 6:45 AM UTC

Is there some nice explanation of how the projections between various EPSG codes work? I converted one projection into another but in QGIS or in python pyproj, but except for the very basics I have no idea what is going on.

Re: Show HN: Interactively explore different map projections

#10

Post by mitchtbaum » Sat, May 20, 2017, 11:10 AM UTC

m1el wrote: post #3

There's a few map projections I really like that don't have most of these problems: HELAPIx[0] and Dymaxion map[1]. HELAPIx is designed to have pixels of the same area, and Dymaxion is designed to have the least distortion. [0]: http://healpix.jpl.nasa.gov/ [1]: https://en.wikipedia.org/wiki/Dymaxion_map

I like Cahill-Keyes: http://www.cartotalk.com/index.php?showtopic=9406 (d3.js animation included).