{"id":1755,"date":"2016-09-18T00:00:32","date_gmt":"2016-09-17T22:00:32","guid":{"rendered":"https:\/\/fabsk.eu\/blog\/?p=1755"},"modified":"2023-08-06T10:28:11","modified_gmt":"2023-08-06T08:28:11","slug":"pourquoi-laltitude-du-gps-semble-fausse-sur-android","status":"publish","type":"post","link":"https:\/\/fabsk.eu\/blog\/2016\/09\/18\/pourquoi-laltitude-du-gps-semble-fausse-sur-android\/","title":{"rendered":"Pourquoi l&rsquo;altitude du GPS semble fausse sur Android"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"344\" src=\"https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air-1024x344.jpg\" alt=\"Peinture de J\u00e9sus en l\u00e9vitation sur un fond de nuages et de collines rocailleuses.\" class=\"wp-image-2874\" srcset=\"https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air-1024x344.jpg 1024w, https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air-300x101.jpg 300w, https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air-768x258.jpg 768w, https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air-1536x516.jpg 1536w, https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air-624x210.jpg 624w, https:\/\/fabsk.eu\/blog\/wp-content\/uploads\/2023\/07\/jesus-marche-air.jpg 1904w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption class=\"wp-element-caption\">J\u00e9sus lui aussi avait un probl\u00e8me d&rsquo;altitude GPS.<\/figcaption><\/figure>\n\n\n\n<p>Bizarrement, plusieurs de mes programmes Android (SatStat, Firefox) rapportent une altitude fausse (50m de plus). Par contre GPS Test retourne une altitude qui me semble plus correcte. Je supputait que cette diff\u00e9rence \u00e9tait due au fait que le calcul \u00e9tait fait par les programmes (d&rsquo;apr\u00e8s les donn\u00e9es GPS brutes). En fait, l&rsquo;API&nbsp;Android fournit l&rsquo;altitude, mais celle-ci est relative au <a href=\"https:\/\/fr.wikipedia.org\/wiki\/WGS_84\">syst\u00e8me g\u00e9od\u00e9sique WGS 84<\/a> qui est diff\u00e9rent du niveau moyen de la mer. Une conversion est donc requise, ce que fait GPS Test. Information sur <a href=\"https:\/\/stackoverflow.com\/questions\/9249193\/how-to-calculate-the-altitude-above-from-mean-sea-level\">Stackoverflow<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Bizarrement, plusieurs de mes programmes Android (SatStat, Firefox) rapportent une altitude fausse (50m de plus). Par contre GPS Test retourne une altitude qui me semble plus correcte. Je supputait que cette diff\u00e9rence \u00e9tait due au fait que le calcul \u00e9tait fait par les programmes (d&rsquo;apr\u00e8s les donn\u00e9es GPS brutes). En fait, l&rsquo;API&nbsp;Android fournit l&rsquo;altitude, mais [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[27,31,6],"tags":[],"class_list":["post-1755","post","type-post","status-publish","format-standard","hentry","category-android","category-firefox","category-informatique"],"_links":{"self":[{"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/posts\/1755","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/comments?post=1755"}],"version-history":[{"count":4,"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/posts\/1755\/revisions"}],"predecessor-version":[{"id":2951,"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/posts\/1755\/revisions\/2951"}],"wp:attachment":[{"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/media?parent=1755"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/categories?post=1755"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fabsk.eu\/blog\/wp-json\/wp\/v2\/tags?post=1755"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}