My new map projections website

General discussion of map projections.
Atarimaster
Posts: 446
Joined: Fri Nov 07, 2014 2:43 am

My new map projections website

Post by Atarimaster »

Hello,

a few days ago, I launched a website regarding map projections.

Mostly it’s about comparing map projections visually (although I did add some articles containing basic informations for beginners, too).
Basically, you can choose two map projections you’d like to compare, and they get layered on top of each other. By switching back and forth, it’s very easy to see the differences even if the projections are very similar. Also, this might be helpful if you want to explore the distortions of the given projections.

In case you’re interested, just pay me a visit at
http://map-projections.net/

A german version is available at
http://kartenprojektionen.de/

I’d be happy to receive your comments, criticism, suggestions…

Kind regards,
Tobias
Piotr
Posts: 313
Joined: Thu Mar 23, 2017 12:27 pm

Re: My new map projections website

Post by Piotr »

Please add polar and hemispheric Lambert azimuthal equal-area.

At which meridian are hemispheric projections cut?
Piotr
Posts: 313
Joined: Thu Mar 23, 2017 12:27 pm

Re: My new map projections website

Post by Piotr »

I'll also add Goodeinterrupted Mollweide, Hemispheric Sinusoidal, Boggs Uninterrupted, Boggs hemispheric and Goode hemispheric.
Piotr
Posts: 313
Joined: Thu Mar 23, 2017 12:27 pm

Re: My new map projections website

Post by Piotr »

Gall isographic has equidistant meridians, but it's listed as "Compromise". Sinusoidal, Sinusoidal (i.) and Stab-Werner are both equal-area and equidistant, but this page only lists equal-area.
Atarimaster
Posts: 446
Joined: Fri Nov 07, 2014 2:43 am

Re: My new map projections website

Post by Atarimaster »

Thanks for your suggestions!
Piotr wrote:Please add polar and hemispheric Lambert azimuthal equal-area.
I can add the polar aspect, the hemispheric is already there:
http://map-projections.net/single-view/ ... -hemi-110w
Piotr wrote: At which meridian are hemispheric projections cut?
Download this zipped Geocart file and see: ;)
http://map-projections.net/download/hem ... i.geo3.zip

I’m going to reply to your other comments as well, but for the moment, I don’t have time for that.
Last edited by Atarimaster on Sun Apr 09, 2017 10:53 am, edited 1 time in total.
Piotr
Posts: 313
Joined: Thu Mar 23, 2017 12:27 pm

Re: My new map projections website

Post by Piotr »

If I'm not mistaken, that means 20 degrees.

http://comparemaps.net.dev/ is invalid link!

What I find confusing is that the hemispheric version is called Azimuthal equal-area Projection, while the equatorial one is called Lambert Azimuthal Projection.

Also, stereographic (polar, equatorial, clipped like you did with Mercator, you can't add hemispheric version because it's already there) would be nice.
Atarimaster
Posts: 446
Joined: Fri Nov 07, 2014 2:43 am

Re: My new map projections website

Post by Atarimaster »

Piotr wrote: http://comparemaps.net.dev/ is invalid link!
Sorry, I copied the link of my local development environment. :oops:
It’s valid now.

And about the other stuff: See you tomorrow!
Regards,
Tobias
Atarimaster
Posts: 446
Joined: Fri Nov 07, 2014 2:43 am

Re: My new map projections website

Post by Atarimaster »

Piotr wrote:I'll also add Goodeinterrupted Mollweide, Hemispheric Sinusoidal, Boggs Uninterrupted, Boggs hemispheric and Goode hemispheric.
I’m going to add Boggs Uninterrupted soon.
As for the interrupted projections… I’m a bit unhappy with the choice of interrupted projections that I show on my website anyway. At that time when I selected them, it seemed like a good idea to me, but now I’m not so sure about it anymore. Moreover, as you know, you can interrupt a hell of a lot of projections, in various ways. I could easily pour a bunch of interrupted variants onto the website and then boast that I’ve got a thousand different projections on my site, but I think that would be counterproductive.

The bottom line is: At some point in the future, I’m going to think about what to do with the interrupted projections. Some might be replaced, and some might be added, and then, I’ll take your suggestions into account. But don’t hold your breath yet…

Piotr wrote:Gall isographic has equidistant meridians, but it's listed as "Compromise".
Good point! I’ll change that.
Piotr wrote:Sinusoidal, Sinusoidal (i.) and Stab-Werner are both equal-area and equidistant, but this page only lists equal-area.
Well.
Back when I wrote the scripts and build the underlying database, I designed the metric properties to be mutually exclusive. That means that currently I just can’t mark a projection as being equal-area and equidistant as well. Of course, I could change that, but apart from being a fair bit of work: The thing about the term »equidistant« is that it’s not uniformly defined, there are various definitions. So in the case of the projections you mention, I simply decided to put them to the equal-area group because that term is strictly defined.

Piotr wrote: What I find confusing is that the hemispheric version is called Azimuthal equal-area Projection, while the equatorial one is called Lambert Azimuthal Projection.
You’re right, that is confusing.
I can’t remember why I chose that kind of naming.
I guess I just slipped at that time when I was rushing through more than 80 projections and created various images for each of them.
Piotr wrote: Also, stereographic (polar, equatorial, clipped like you did with Mercator, you can't add hemispheric version because it's already there) would be nice.
Polar and equatorial stereographic is a good suggestion.
I’m going to think about the most advantageous configuration (in terms of the website).

Thanks again for you comments & suggestions!
Kind regards,
Tobias
Piotr
Posts: 313
Joined: Thu Mar 23, 2017 12:27 pm

Re: My new map projections website

Post by Piotr »

For equal-area equidistant projections, a fix to paradoxes like "What if equal-area is checked but not equidistant?" would be to have a new category, Equal-area and Equidistant.

American polyconic seems to preserve distances along parallels, thus, equidistant.
Atarimaster
Posts: 446
Joined: Fri Nov 07, 2014 2:43 am

Re: My new map projections website

Post by Atarimaster »

I just updated the site.

I’ve added the uninterrupted Boggs eumorphic and the polar aspect of Lambert’s azimuthal equal area-projection and renamed the Lambert azimuthal projection. Gall Isographic is now listed as "equidistant". Furtherly, I’ve added the Bonne projection I was profoundly convinced that I had added this one a long time ago but obviously I didn’t… :oops:

Other changes are, again, related to Wagner:
A new part of my Wagner article series showing Wagner’s own variations of Wagner VII, which I refer to as Wagner VII.b, VII.c and VII.d, since I’m not aware of any established names.
I've added Aribert Peters’ Entfernungsbezogene Weltkarte (distance-related map), which is another Wagner VII variant, and Canters’ optimization of Wagner IX.
The projection we’ve talked about in this thread is listed as Nell-Hammer modified.
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