Talk:Map projection

"The projections are described in terms of placing a gigantic surface in contact with the Earth" - violation of NPOV? Who defined the surface as gigantic? Is that encyclopedic? Euro2023 (talk) 23:54, 9 January 2023 (UTC)

Do you believe that the use of English adverbs and adjectives is automatically unencyclopedic, and that encyclopedic language should be limited only to nouns, verbs, and connecting words? —David Eppstein (talk) 00:06, 10 January 2023 (UTC)

I changed the wording to convey the same meaning. Gigantic is relative, and map projection is not only limited to the Earth. GeogSage ^{(⚔Chat?⚔)} 00:23, 10 January 2023 (UTC)

"If maps were projected as in light shining through a globe onto a developable surface, then the spacing of parallels would follow a very limited set of possibilities." - How that? Why should there be a limitation? Is there projection of a particular point on a surface that cannot be reached by "light shining through a globe"? Euro2023 (talk) 15:45, 10 January 2023 (UTC)

The set of projections defined by projective geometry is grossly limited compared to the the set that is possible from more general mathematical transformations permitted in the common definition of cylindrical projection. Strebe (talk) 19:24, 10 January 2023 (UTC)

"in the common definition of cylindrical projection" isn't contained in the claim, or the text next to it, that I copied from the article. And where is the evidence that such a "common definition of cylindrical projection" exists? https://en.wikipedia.org/w/index.php?search=%22common+definition+of+cylindrical+projection%22&title=Special:Search&profile=advanced&fulltext=1&ns0=1 : "There were no results matching the query." Euro2023 (talk) 19:36, 10 January 2023 (UTC)

The common definition, whatever it is or isn’t, does encompass the Mercator projection, as per all the literature in existence. Meanwhile, the Mercator projection cannot be represented just by “light shining through a globe onto a developable surface”. Therefore, given that we have an example (and scores more) of cylindrical projections that cannot be represented by “light shining through a globe onto a developable surface”, the statement is fine. Strebe (talk) 21:33, 10 January 2023 (UTC)

Although this article does address the position of the theoretical light source, as far as I can see (as of 2026-1-15) this does not appear to be until well over half way through the article (section "azimuth…"). As far as I can tell, the assumption for most of the article is that the light source is at the centre of the globe - or the question is not addressed at all. I feel this - a rather fundamental aspect of the subject - should be, in a clear manner. addressed much earlier in the discussion.G6JPG (talk) 17:16, 15 January 2026 (UTC)

“Light shining through a globe” is not relevant to map projections in general, as per the earlier comments in this thread. It is little more than a conceptual device, and even then, of debatable value. Strebe (talk) 17:36, 15 January 2026 (UTC)

I have created a proposal page for Map projections. Please feel free to add your name to the support section, discuss, disseminate, and otherwise edit. Thanks. Strebe (talk) 01:26, 12 January 2023 (UTC) @Justinkunimune:@GeogSage:@Elphion:@Fgnievinski:@Alvesgaspar:@Paul Koning:@Peter Mercator:@EdwardLane:@Jacobolus:@Apocheir:

See also, geoinformatics has 2 commas in a row separated by a space. I can't figure out if there's something missing or how to remove one of them. 82.135.221.10 (talk) 15:41, 7 July 2024 (UTC)

Fixed, thanks! The extra commas were part of the geoinformatics article's short description. Just plain Bill (talk) 16:02, 7 July 2024 (UTC)

Are we going to start using Equal Earth map as a base projection as it is more correct?

• If so who decides, and how do we go about it?

--always ping me-- Goran tek-en (talk) 11:43, 6 September 2026 (UTC)

@Goran tek-en: In what ways is it "more correct"? Just plain Bill (talk) 19:48, 6 September 2026 (UTC)

This has been a pop culture thing lately, I've seen it on Reddit quite a bit. So maps distort one of four things: Area, direction, shape, and distance. Every projection must balance these four things. Recently, a push has been made to favor the equal area projection as a push back against the historic use of the Mercator projection, which distorts area to preserve direction. Depending on application, you will need to choose a different projection.

• Thematic maps like choropleth maps require an equal area projection. Every choropleth map using a different projection is inappropriate. Most choropleth maps we see are misleading because of this error.
• Navigation maps like we see in Google Maps require a projection that preserves direction, like the Web Mercator.

There are a wide variety of List of map projections, and there are infinite possible ways to project the Earth. The one we choose will be based entirely on what we want to show, and where it is on the globe. Personally, for "general reference world maps," used for educational purposes, I'm partial to the Boggs eumorphic projection

as it does a good job of illustrating that a projection is a sphere being flattened. GeogSage ^{(⚔Chat?⚔)} 20:10, 6 September 2026 (UTC)

@GeogSage @Just plain Bill

• Both Equal Earth map and Boggs eumorphic projection are equal-area pseudocylindrical maps so they show areas more equal than many other projectios. It has also been accepted by UN which gives it some weight in trying to have a projection that most countries can agree on.
• I'm mainly thinking about maps that are created at commons and here to show different things within countries or between countries (hope you understand the general idea). In many of those maps the size of all the different countries is very important and basic. So to be able to show that would be an improvement from what is often used today.
• Yes there are many different types of projections which all has there advantages in different situations or what you want to show and should be used when they are better for that purpose.
• To me personally it is important that we use a projection that show the relationships between countries as truly as possible. This to fulfill the basic ideas of commons and wikipedia as parts of wikimedias Shared values.

Shared values;

*a collection of values shared by individuals (freedom of speech, knowledge for everyone, community sharing, etc. --always ping me-- Goran tek-en (talk) 21:23, 6 September 2026 (UTC)

"Accepted by the UN." Again, I've seen this become quite a fiasco in public discourse recently, but the United Nations is not an authority on cartographic conventions. The "Equal Earth Map" is just one of many options, and I personally think it is a vanity project by the authors to push for a "new map" rather then use some of the countless existing projections. The topic is more aligned with the kind of click bait issues that capture public attention then actual issues in cartography. Further, on Wikipedia we are not here to right great wrongs. There are reasons to consider using an equal area projection over others. There are a lot of problems with how maps are made/handled on Wikipedia. A lot of problems. It's actually kind of a nightmare how bad it is, and how little most editors actually care. Defaulting to a single projection, or class of projections, is likely to make more problems then it solves. A flow chart for specific situations, locations, and appropriate projections would be the best solution. Even then, it would never be able to comprehensively address every situation. While I make it a personal practice to never use custom projections as I believe it makes it difficult for others to reproduce my work (all maps should be able to be reproduced so others can check them), making custom projections for specific locations is accepted practice taught in introductory cartography classes. We have an entire list of projections. There is never one right answer, but usually there are many wrong ones. Sometimes, an equal area map is the wrong answer. Some other options to point out:

• The Winkel tripel projection minimizes three types of distortion, and is used by National Geographic.
• The Tobler hyperelliptical projection was made by Waldo R. Tobler. Not widely used, but worth mentioning.
• The Dymaxion map uses a similar approach to the Boggs eumorphic projection, and minimizes distortion of both area and shape.

GeogSage ^{(⚔Chat?⚔)} 23:44, 6 September 2026 (UTC)