Talk:Map projection

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Map projection was one of the Geography and places good articles, but it has been removed from the list. There are suggestions below for improving the article to meet the good article criteria. Once these issues have been addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.

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December 12, 2005	Good article nominee	Listed
September 27, 2008	Good article reassessment	Delisted

Current status: Delisted good article

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Hourglass Projection, and many more[edit]

There is no page or article references for the stated projection.

here is a book that has a diagram

here is a web page with links to various projections — Preceding unsigned comment added by 14.200.179.169 (talk) 12:48, 31 March 2020 (UTC)[reply]

Thank you, those look like useful references.

Alas, the Vespucci site seems to be offline today, but identical (as far as I can tell) copies of the information on that site are available at:

My understanding from p. 161-163 of the book you mentioned,

(Mark Monmonier. "Rhumb Lines and Map Wars: A Social History of the Mercator Projection".)

is that the Snyder "hourglass projection" was never seriously intended to be useful, but is more of a sarcastic way of pointing out that perhaps there are more important characteristics of a map projection than "equal area".

I feel that there are so many map projections that there's not room in this "map projection" overview article for the Snyder "hourglass projection",

but perhaps that projection might be relevant in the equal-area map article. --DavidCary (talk) 03:36, 24 December 2020 (UTC)[reply]

Classification of old maps without projection?[edit]

In Commons we have problem with old maps and their projections. Wise advices will be needed in here: Commons:Commons:Categories for discussion/2018/01/Category:Maps with unidentified projection--Estopedist1 (talk) 10:39, 29 November 2021 (UTC)[reply]

Gigantic[edit]

"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)[reply]

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)[reply]

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)[reply]

light shining through a globe - then the spacing of parallels would follow a very limited set of possibilities[edit]

"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." [1] - 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)[reply]

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)[reply]

"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)[reply]

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)[reply]

WikiProject[edit]

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:[reply]