{"action":"closed","issue":{"url":"https://api.github.com/repos/paparazzi/paparazzi/issues/1006","labels_url":"https://api.github.com/repos/paparazzi/paparazzi/issues/1006/labels{/name}","comments_url":"https://api.github.com/repos/paparazzi/paparazzi/issues/1006/comments","events_url":"https://api.github.com/repos/paparazzi/paparazzi/issues/1006/events","html_url":"https://github.com/paparazzi/paparazzi/issues/1006","id":51032921,"number":1006,"title":"cleanup/document altitude definitions: ellipsoid vs. geoid (msl)","user":{"login":"flixr","id":104257,"avatar_url":"https://avatars.githubusercontent.com/u/104257?v=3","gravatar_id":"","url":"https://api.github.com/users/flixr","html_url":"https://github.com/flixr","followers_url":"https://api.github.com/users/flixr/followers","following_url":"https://api.github.com/users/flixr/following{/other_user}","gists_url":"https://api.github.com/users/flixr/gists{/gist_id}","starred_url":"https://api.github.com/users/flixr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/flixr/subscriptions","organizations_url":"https://api.github.com/users/flixr/orgs","repos_url":"https://api.github.com/users/flixr/repos","events_url":"https://api.github.com/users/flixr/events{/privacy}","received_events_url":"https://api.github.com/users/flixr/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/paparazzi/paparazzi/labels/Airborne","name":"Airborne","color":"37b6d6"},{"url":"https://api.github.com/repos/paparazzi/paparazzi/labels/Documentation","name":"Documentation","color":"e102d8"},{"url":"https://api.github.com/repos/paparazzi/paparazzi/labels/Refactoring","name":"Refactoring","color":"bfe5bf"}],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":11,"created_at":"2014-12-04T21:40:54Z","updated_at":"2015-11-04T13:42:07Z","closed_at":"2015-11-04T13:42:07Z","body":"Currently we are mixing up different altitude definitions in some cases/messages which clearly needs to be consolidated, cleaned up and documented.\r\n\r\nWe usually have global altitude as either\r\n- alt above WGS84 reference ellipsoid\r\n- Height above Mean Sea Level (hmsl), so altitude above geoid)\r\n\r\nSee also differences explained at https://wiki.paparazziuav.org/wiki/Altitude_definitions\r\n\r\nSome things to check/fix/consolidate/document:\r\n- fixedwing waypoint altitude seems to be passed as hmsl\r\n- LLA coordinates usually have alt above ellipsoid (gps datum)\r\n- in UtmCoor_f struct we say that alt is above ellipsoid (and assume that in conversion functions), but seems it is filled with hmsl in some cases\r\n- etc...\r\n\r\n[LtpDef] (http://docs.paparazziuav.org/v5.2/structLtpDef__f.html) has alt above ellipsoid in LLA coordinates and an addtional hmsl field\r\n\r\n<bountysource-plugin>\r\n---\r\nWant to back this issue? **[Post a bounty on it!](https://www.bountysource.com/issues/6777996-cleanup-document-altitude-definitions-ellipsoid-vs-geoid-msl?utm_campaign=plugin&utm_content=tracker%2F10895&utm_medium=issues&utm_source=github)** We accept bounties via [Bountysource](https://www.bountysource.com/?utm_campaign=plugin&utm_content=tracker%2F10895&utm_medium=issues&utm_source=github).\r\n</bountysource-plugin>"}}