Talk:Quadrilateralized spherical cube: Difference between revisions

Content deleted Content added

Inline

Revision as of 09:19, 13 December 2022

Maps Start‑class

	This article is within the scope of WikiProject Maps, a collaborative effort to improve the coverage of Maps and Cartography on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.MapsWikipedia:WikiProject MapsTemplate:WikiProject MapsMaps articles
Start	This article has been rated as Start-class on Wikipedia's content assessment scale.
???	This article has not yet received a rating on the project's importance scale.

Guild of Copy Editors

This article was copy edited by a member of the Guild of Copy Editors.Guild of Copy EditorsWikipedia:WikiProject Guild of Copy EditorsTemplate:WikiProject Guild of Copy EditorsGuild of Copy Editors articles

[Untitled]

The too-technical and expert-opinion tags were added without comment or discussion, and IMO do not (or no longer) apply. Odysseus1479 (talk) 19:33, 6 November 2010 (UTC)[reply]

Projection?

This article is entirely about storage, what about the actual projection? Qartar (talk) 06:20, 22 July 2011 (UTC)[reply]

Indeed, the one part that seems about to explain the projection (conversion from bin numbers to coordinates) is a mere sentence fragment: "The conversion between bin numbers and coordinates is straightforward: if four-byte integers are used for the bin numbers the maximum practical depth, which uses 31 of the 32 bits and results in a bin size of 0.0922 square arcminutes (7.80 nanosteradians)." Can anyone work out what this is trying to say? 69.50.14.73 (talk) 16:49, 22 September 2014 (UTC)[reply]

Here, I believe, is an example projection - http://www.progonos.com/furuti/MapProj/Normal/ProjPoly/Img/cbGn-s100h-Combi.png if anyone cares to include it in the article...

I think those are gnomonic projections (one with the poles at the corners, the other face-centred), not the equal-area curvilinear projection mentioned in the article. And I don’t see a free licence on the site’s home-page; we presume images to be copyrighted unless there’s an explicit statement to the contrary, so we probably can’t use that image anyway.—Odysseus 1479 21:02, 1 April 2016 (UTC)[reply]

About this talk-section, yes, is important to add some explanations about projection... See also proj.org/QSC... But please, help edit collaboration, not reverting text, but edit enhancing the content offered by collaboration. Krauss (talk) 13:33, 19 February 2022 (UTC)[reply]

Revert not make sense, please add S2

See also the (most popular and) similar S2 Geometry system. PROJ implementation of S2 used QSC, see https://github.com/OSGeo/PROJ/pull/2749

So, if it is all ok, please add, with better English, the S2 citation. Krauss (talk) 13:28, 19 February 2022 (UTC)[reply]

Done. Is there a better reference for S2? A paper, or more independent coverage? Apocheir (talk) 21:54, 19 February 2022 (UTC)[reply]

Is it exactly equal-area?

The COBE sky cube described at https://lambda.gsfc.nasa.gov/product/cobe/skymap_info_new.html says "All COBE map data are presented in a quadrilateralized spherical projection, an approximately equal-area projection (to within a few percent) in which the celestial sphere is projected onto an inscribed cube.". ThomasTC (talk) 09:19, 13 December 2022 (UTC)[reply]

@@ Line 24: / Line 24: @@
 :Done. Is there a better reference for S2? A paper, or more independent coverage? [[User:Apocheir|Apocheir]] ([[User talk:Apocheir|talk]]) 21:54, 19 February 2022 (UTC)
+== Is it exactly equal-area? ==
+The COBE sky cube described at https://lambda.gsfc.nasa.gov/product/cobe/skymap_info_new.html says "All COBE map data are presented in a quadrilateralized spherical projection, an approximately equal-area projection (to within a few percent) in which the celestial sphere is projected onto an inscribed cube.". [[User:ThomasTC|ThomasTC]] ([[User talk:ThomasTC|talk]]) 09:19, 13 December 2022 (UTC)