{"action":"created","issue":{"url":"https://api.github.com/repos/judgej/Proj4/issues/6","repository_url":"https://api.github.com/repos/judgej/Proj4","labels_url":"https://api.github.com/repos/judgej/Proj4/issues/6/labels{/name}","comments_url":"https://api.github.com/repos/judgej/Proj4/issues/6/comments","events_url":"https://api.github.com/repos/judgej/Proj4/issues/6/events","html_url":"https://github.com/judgej/Proj4/issues/6","id":113148072,"number":6,"title":"UTM - is the zone part of the coordiate or not?","user":{"login":"judgej","id":395934,"avatar_url":"https://avatars.githubusercontent.com/u/395934?v=3","gravatar_id":"","url":"https://api.github.com/users/judgej","html_url":"https://github.com/judgej","followers_url":"https://api.github.com/users/judgej/followers","following_url":"https://api.github.com/users/judgej/following{/other_user}","gists_url":"https://api.github.com/users/judgej/gists{/gist_id}","starred_url":"https://api.github.com/users/judgej/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/judgej/subscriptions","organizations_url":"https://api.github.com/users/judgej/orgs","repos_url":"https://api.github.com/users/judgej/repos","events_url":"https://api.github.com/users/judgej/events{/privacy}","received_events_url":"https://api.github.com/users/judgej/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-10-24T09:45:17Z","updated_at":"2016-03-30T21:47:07Z","closed_at":null,"body":"This one has me scratching my head a little.\r\n\r\nInherited from Proj.4 and all its successors to this point, a UTM zone is a part of the projection and NOT a part of the coordinate, This means you set up the projection for a single zone, then run all your conversions through that. That is kind of okay when you are going from UTM to another coordinate system, but not the other way around, since you don't know the zone of a longitude until you pass it to the projection to work it out (okay, you can work it out, but the point is, you should not have to do a part of the projection's work to find it out what parameters it needs for a coordinate before you can even create the projection - it seems back-to-front).\r\n\r\nSo my approach will be to allow you to set the zone for a projection if you ave a bunch of coordinates to transform, but allow the coordinate to define the zone and that takes precedence. An x/y coordinate from a UTM projected map is of no use without knowing this additional information (i.e. which hemisphere and/or MGRS latitude zone, and which longitude zone the x/y is bound to)."},"comment":{"url":"https://api.github.com/repos/judgej/Proj4/issues/comments/203648659","html_url":"https://github.com/judgej/Proj4/issues/6#issuecomment-203648659","issue_url":"https://api.github.com/repos/judgej/Proj4/issues/6","id":203648659,"user":{"login":"judgej","id":395934,"avatar_url":"https://avatars.githubusercontent.com/u/395934?v=3","gravatar_id":"","url":"https://api.github.com/users/judgej","html_url":"https://github.com/judgej","followers_url":"https://api.github.com/users/judgej/followers","following_url":"https://api.github.com/users/judgej/following{/other_user}","gists_url":"https://api.github.com/users/judgej/gists{/gist_id}","starred_url":"https://api.github.com/users/judgej/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/judgej/subscriptions","organizations_url":"https://api.github.com/users/judgej/orgs","repos_url":"https://api.github.com/users/judgej/repos","events_url":"https://api.github.com/users/judgej/events{/privacy}","received_events_url":"https://api.github.com/users/judgej/received_events","type":"User","site_admin":false},"created_at":"2016-03-30T21:47:07Z","updated_at":"2016-03-30T21:47:07Z","body":"I suspect the zone is a part of the projection, but the projection instance MUST be a part of a UTM projection point."}}