Community Wishlist Survey 2019/Archive/Mapframe does not work well at the poles

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◄ Back to Archive  The survey has concluded. Here are the results!


Withdrawn by proposer

  • Who would benefit: Users/editors working on topics that are close to the north or south pole
  • Proposed solution: Use a different coordinate system that works better at the poles
  • More comments: This is probably more tricky than it sounds, as it requires a fundamental logic change in Kartographer to handle a different coordinate system. It was recently marked as "declined" on phabricator as "It's unlikely we'll have the resources in the foreseeable future to support multiple projections."

Discussion

  • Hi @ Mike Peel. You suggest Kartographer use a coordinate system that will solve the problem of distorted, empty polar maps. Do you know of such a system? What are the alternatives and the tradeoffs each brings? Anyone? —JMatazzoni (WMF) (talk) 04:15, 3 November 2018 (UTC)
Comment: en:List of map projections provides a useful overview. Of those covered, several feature lower distortion in the polar regions than the Mercator; the most readily implemented might be the en:Miller cylindrical projection which retains a rectangular shape and somewhat improves the poles. A much better alternative IMO is the en:Hammer projection; its downside is the ellipsoidal shape, which requires more screen real estate for a given resolution of features. --Elmidae (talk) 12:06, 3 November 2018 (UTC)
@JMatazzoni (WMF): It's complicated. In my day job, we use en:HEALPix to pixelize the whole astronomical sky - and then you can render individual patches using cartesian maps in order to display them (cartesian maps are fine as long as they're smaller than a few degrees on a side). The issue is that a single rendered map is used for the whole of the globe. However, I've just had a look at the south pole on OpenStreetMap, and as they use the same system they have the same problem - so it's not actually possible to edit the map at the poles, which makes displaying the map correctly at the poles rather redundant. As such, I'm withdrawing this proposal. Thanks. Mike Peel (talk) 14:16, 3 November 2018 (UTC)
@Mike Peel: I'm a bit late, but it is actually possible to edit close to the poles (or at least it's possible to make mechanical edits close to them), even though the objects don't get displayed on the map. However, almost all OSM maps and renderers (except possibly Marble) only use Mercator, and there is basically nothing there right now, possibly because most satellite imagery that OSM can use is also Mercator (and so no imagery tiles are generated south of about 85°). Jc86035 (talk) 15:42, 17 November 2018 (UTC)

Request withdrawn Mike Peel (talk) 14:16, 3 November 2018 (UTC)