{"action":"created","issue":{"url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/issues/32","repository_url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson","labels_url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/issues/32/labels{/name}","comments_url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/issues/32/comments","events_url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/issues/32/events","html_url":"https://github.com/Reading-eScience-Centre/coveragejson/issues/32","id":117104657,"number":32,"title":"Curvilinear grids / coordinate parameters","user":{"login":"neothemachine","id":530988,"avatar_url":"https://avatars.githubusercontent.com/u/530988?v=3","gravatar_id":"","url":"https://api.github.com/users/neothemachine","html_url":"https://github.com/neothemachine","followers_url":"https://api.github.com/users/neothemachine/followers","following_url":"https://api.github.com/users/neothemachine/following{/other_user}","gists_url":"https://api.github.com/users/neothemachine/gists{/gist_id}","starred_url":"https://api.github.com/users/neothemachine/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/neothemachine/subscriptions","organizations_url":"https://api.github.com/users/neothemachine/orgs","repos_url":"https://api.github.com/users/neothemachine/repos","events_url":"https://api.github.com/users/neothemachine/events{/privacy}","received_events_url":"https://api.github.com/users/neothemachine/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/labels/needs%20discussion","name":"needs discussion","color":"207de5"}],"state":"open","locked":false,"assignee":null,"milestone":{"url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/milestones/2","html_url":"https://github.com/Reading-eScience-Centre/coveragejson/milestones/future","labels_url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/milestones/2/labels","id":1521811,"number":2,"title":"future","description":"","creator":{"login":"neothemachine","id":530988,"avatar_url":"https://avatars.githubusercontent.com/u/530988?v=3","gravatar_id":"","url":"https://api.github.com/users/neothemachine","html_url":"https://github.com/neothemachine","followers_url":"https://api.github.com/users/neothemachine/followers","following_url":"https://api.github.com/users/neothemachine/following{/other_user}","gists_url":"https://api.github.com/users/neothemachine/gists{/gist_id}","starred_url":"https://api.github.com/users/neothemachine/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/neothemachine/subscriptions","organizations_url":"https://api.github.com/users/neothemachine/orgs","repos_url":"https://api.github.com/users/neothemachine/repos","events_url":"https://api.github.com/users/neothemachine/events{/privacy}","received_events_url":"https://api.github.com/users/neothemachine/received_events","type":"User","site_admin":false},"open_issues":6,"closed_issues":0,"state":"open","created_at":"2016-01-20T10:08:05Z","updated_at":"2016-04-19T08:40:28Z","due_on":null,"closed_at":null},"comments":29,"created_at":"2015-11-16T11:28:44Z","updated_at":"2016-05-03T15:03:51Z","closed_at":null,"body":"Continuing from https://github.com/Reading-eScience-Centre/coveragejson/issues/24#issuecomment-151551355\r\n\r\n- curvilinear grids -> lat/lon are best exposed as ranges (as \"coordinate\" parameter) and not inside the domain\r\n- having \"coordinate parameters\" makes sense, e.g. for DEMs where the domain is just x and y, and the range is z\r\n- CRS definition for coordinate parameters should be similar to how it's done in the domain -> problem: how to specify CRS for single axis like \"latitude\"? maybe use parameter groups for that?"},"comment":{"url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/issues/comments/216557400","html_url":"https://github.com/Reading-eScience-Centre/coveragejson/issues/32#issuecomment-216557400","issue_url":"https://api.github.com/repos/Reading-eScience-Centre/coveragejson/issues/32","id":216557400,"user":{"login":"jonblower","id":6309993,"avatar_url":"https://avatars.githubusercontent.com/u/6309993?v=3","gravatar_id":"","url":"https://api.github.com/users/jonblower","html_url":"https://github.com/jonblower","followers_url":"https://api.github.com/users/jonblower/followers","following_url":"https://api.github.com/users/jonblower/following{/other_user}","gists_url":"https://api.github.com/users/jonblower/gists{/gist_id}","starred_url":"https://api.github.com/users/jonblower/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jonblower/subscriptions","organizations_url":"https://api.github.com/users/jonblower/orgs","repos_url":"https://api.github.com/users/jonblower/repos","events_url":"https://api.github.com/users/jonblower/events{/privacy}","received_events_url":"https://api.github.com/users/jonblower/received_events","type":"User","site_admin":false},"created_at":"2016-05-03T15:03:51Z","updated_at":"2016-05-03T15:03:51Z","body":"> Should ReferencingByCoordinates also work for composite axes like in a trajectory?\r\n\r\nMaybe, but I don't know why you would do this, rather than just specifying the coordinates directly in the trajectory?\r\n\r\n> In which case would a client want to have the 2D curvilinear grid coordinates instead of a resampled grid in another projection or lon/lat?\r\n\r\nA resampled (rasterized) grid would lose the shape of the grid cells, which might be important when zoomed in a long way. Sometimes there is a large difference in size between the smallest and largest grid cells, meaning that you'd have to pick a very small grid cell size to accurately record the grid. Also, sometimes the rasterized grid would have large empty regions.\r\n\r\n> Including 2D coordinates for a curvilinear grid precautionally is only a solution for a small number of advanced clients I think, since it is way harder to process, render etc.\r\n\r\nI dunno - for many clients I think it would be easier to read WGS84 lat-lon coordinates than figure out how to do a projection. Also, sometimes curvilinear coordinates is all you have - there isn't always a native projection at all (e.g. ocean model).\r\n\r\n> How far do curvilinear grids overlap with the MultiPolygon domain type?\r\n\r\nGood question. MultiPolygon might do the job, except that it does not record the grid cell centres, which might be important. (And these are not necessarily the centroids of the grid cells, I don't think.)\r\n\r\n> It would be good to have some very specific use cases in the web context before we start thinking about how to implement it.\r\n\r\nA use case would be a coastal-ocean model that follows the coastline, estuaries etc. A bit like the \"unstructured\" grids, but with a quadrilateral geometry instead of triangular. Maybe a single mechanism could be used for polygons of any shape (like in VTK).\r\n\r\n\r\n\r\n\r\n"}}