{"id":155687,"date":"2026-04-06T09:17:18","date_gmt":"2026-04-06T16:17:18","guid":{"rendered":"https:\/\/www.geocaching.com\/blog\/?p=155687"},"modified":"2026-04-07T07:52:38","modified_gmt":"2026-04-07T14:52:38","slug":"gladys-west-et-la-revolution-du-gps-blue-switch-day-2026","status":"publish","type":"post","link":"https:\/\/www.geocaching.com\/blog\/2026\/04\/gladys-west-et-la-revolution-du-gps-blue-switch-day-2026\/","title":{"rendered":"Gladys West et la r\u00e9volution du GPS : Blue Switch Day 2026"},"content":{"rendered":"<p>Lorsque les g\u00e9ocacheurs sortent avec un GPS, ils b\u00e9n\u00e9ficient de d\u00e9cennies de recherches scientifiques et math\u00e9matiques de pointe qui ont permis de d\u00e9finir ces coordonn\u00e9es. Derri\u00e8re chaque d\u00e9couverte majeure se cache une math\u00e9maticienne de g\u00e9nie dont les travaux ont contribu\u00e9 \u00e0 rendre possible le GPS moderne : <strong><a href=\"https:\/\/en.wikipedia.org\/wiki\/Gladys_West\">le Dr Gladys West<\/a><\/strong>.<\/p>\n<figure id=\"attachment_155536\" aria-describedby=\"caption-attachment-155536\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-155536\" src=\"https:\/\/www.geocaching.com\/blog\/wp-content\/uploads\/2026\/03\/Gladys-West.jpg\" alt=\"\" width=\"300\" height=\"390\" srcset=\"https:\/\/d3mo08i005h0zn.cloudfront.net\/blog\/uploads\/2026\/03\/Gladys-West.jpg 675w, https:\/\/d3mo08i005h0zn.cloudfront.net\/blog\/uploads\/2026\/03\/Gladys-West-300x390.jpg 300w, https:\/\/d3mo08i005h0zn.cloudfront.net\/blog\/uploads\/2026\/03\/Gladys-West-656x853.jpg 656w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-155536\" class=\"wp-caption-text\">1930 &#8211; 2026<br \/>Image du New York Times.<\/figcaption><\/figure>\n<p><!--more--><\/p>\n<p>Les travaux novateurs de Gladys West visaient \u00e0 r\u00e9soudre un probl\u00e8me d&#8217;une complexit\u00e9 trompeuse : d\u00e9terminer la forme exacte de la Terre.<\/p>\n<p>Dans les ann\u00e9es 1960 et 1970, West a contribu\u00e9 au traitement d&#8217;\u00e9normes quantit\u00e9s de donn\u00e9es satellitaires afin de mod\u00e9liser le <a href=\"https:\/\/en.wikipedia.org\/wiki\/Geoid\">g\u00e9o\u00efde<\/a> terrestre. Comme les satellites gravitent en suivant le champ gravitationnel tout autour de la Terre, il \u00e9tait essentiel de bien comprendre cette forme pour calculer avec pr\u00e9cision les positions \u00e0 la surface de la plan\u00e8te. West a programm\u00e9 les premiers superordinateurs pour analyser des donn\u00e9es oc\u00e9anographiques et satellitaires, produisant ainsi des mod\u00e8les de plus en plus pr\u00e9cis qui ont servi de base au d\u00e9veloppement du <a href=\"https:\/\/en.wikipedia.org\/wiki\/Global_Positioning_System\">syst\u00e8me de positionnement global (GPS)<\/a>. Lorsque les satellites GPS ont \u00e9t\u00e9 mis en service par la suite, ils se sont appuy\u00e9s sur ces mod\u00e8les terrestres pr\u00e9cis pour convertir les signaux satellitaires en coordonn\u00e9es exactes que nous utilisons aujourd\u2019hui pour la navigation, la cartographie et les technologies de localisation.<\/p>\n<p>Le geocaching repose sur un principe d&#8217;une magnifique simplicit\u00e9 : utiliser des coordonn\u00e9es GPS pour trouver des tr\u00e9sors cach\u00e9s aux quatre coins du monde. Mais la magie qui se cache derri\u00e8re ces coordonn\u00e9es repose sur un syst\u00e8me incroyablement sophistiqu\u00e9 de satellites, de signaux de synchronisation et de mod\u00e8les terrestres.<\/p>\n<p>Merci, Gladys West, d&#8217;avoir fait progresser la <a href=\"https:\/\/en.wikipedia.org\/wiki\/Geodesy\">g\u00e9od\u00e9sie<\/a> et la mod\u00e9lisation par satellite, rendant ainsi possible la pr\u00e9cision du geocaching !<\/p>\n<p>C\u00e9l\u00e9brez le Blue Switch Day 2026 en posant une g\u00e9ocache et gagnez votre souvenir du poseur du Blue Switch Day 2026.<\/p>\n<p><strong>Poseur du Blue Switch Day 2026 :<\/strong><\/p>\n<ul>\n<li>Pour gagner ce souvenir, les g\u00e9ocacheurs doivent publier une cache (\u00e0 l&#8217;exception des Events) entre le 1er et le 31 mai 2026.\n<ul>\n<li>N&#8217;importe quelle cache qui ne soit pas un Event (et pas non plus une Adventure Lab\u00ae) compte, \u00e0 condition qu&#8217;elle soit publi\u00e9e entre le 1er et le 31 mai.<\/li>\n<li>N&#8217;oubliez pas que le d\u00e9lai de r\u00e9vision est susceptible de varier ! G\u00e9n\u00e9ralement, un b\u00e9n\u00e9vole de la communaut\u00e9 geocaching commence \u00e0 examiner votre g\u00e9ocache dans les 7 jours. Nous vous recommandons de soumettre votre cache \u00e0 la publication au moins une semaine avant la date limite. Pour en savoir plus sur la proc\u00e9dure de r\u00e9vision des caches, consultez notre <a href=\"https:\/\/www.geocaching.com\/help\/index.php?pg=kb.chapter&amp;id=97&amp;pgid=74\">centre d&#8217;aide<\/a>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>Comment c\u00e9l\u00e9brerez-vous le Blue Switch Day cette ann\u00e9e ?<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Lorsque les g\u00e9ocacheurs sortent avec un GPS, ils b\u00e9n\u00e9ficient de d\u00e9cennies de recherches scientifiques et math\u00e9matiques de pointe qui ont permis de d\u00e9finir ces coordonn\u00e9es. Derri\u00e8re chaque d\u00e9couverte majeure se cache une math\u00e9maticienne de g\u00e9nie dont les travaux ont contribu\u00e9 \u00e0 rendre possible le GPS moderne : le Dr Gladys West.<\/p>\n","protected":false},"author":133,"featured_media":155545,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"episode_type":"audio","audio_file":"","cover_image":"","cover_image_id":"","duration":"","filesize":"","date_recorded":"","explicit":"","block":"","filesize_raw":"","footnotes":""},"categories":[138,131],"tags":[],"series":[],"class_list":["post-155687","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-france","category-local"],"episode_featured_image":"https:\/\/d3mo08i005h0zn.cloudfront.net\/blog\/uploads\/2026\/03\/BBS_2026_SocialSuite_Final_Hider_Blog_800x450.jpg","episode_player_image":"https:\/\/www.geocaching.com\/blog\/wp-content\/plugins\/seriously-simple-podcasting\/assets\/images\/no-album-art.png","download_link":"","player_link":"","audio_player":false,"episode_data":{"playerMode":"dark","subscribeUrls":{"apple_podcasts":{"key":"apple_podcasts","url":"","label":"Apple Podcasts","class":"apple_podcasts","icon":"apple-podcasts.png"},"google_podcasts":{"key":"google_podcasts","url":"","label":"Google Podcasts","class":"google_podcasts","icon":"google-podcasts.png"},"spotify":{"key":"spotify","url":"","label":"Spotify","class":"spotify","icon":"spotify.png"},"stitcher":{"key":"stitcher","url":"","label":"Stitcher","class":"stitcher","icon":"stitcher.png"}},"rssFeedUrl":"https:\/\/www.geocaching.com\/blog\/feed\/podcast\/inside-geocaching-hq-podcast","embedCode":"<blockquote class=\"wp-embedded-content\" data-secret=\"fU7DyHvqnJ\"><a href=\"https:\/\/www.geocaching.com\/blog\/2026\/04\/gladys-west-et-la-revolution-du-gps-blue-switch-day-2026\/\">Gladys West et la r\u00e9volution du GPS : Blue Switch Day 2026<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/www.geocaching.com\/blog\/2026\/04\/gladys-west-et-la-revolution-du-gps-blue-switch-day-2026\/embed\/#?secret=fU7DyHvqnJ\" width=\"500\" height=\"350\" title=\"&#8220;Gladys West et la r\u00e9volution du GPS : Blue Switch Day 2026&#8221; &#8212; Official Blog\" data-secret=\"fU7DyHvqnJ\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script type=\"text\/javascript\">\n\/* <![CDATA[ *\/\n\/*! 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