{"id":384,"date":"2024-09-17T18:16:00","date_gmt":"2024-09-17T16:16:00","guid":{"rendered":"https:\/\/marseilleavantapres.fr\/?p=384"},"modified":"2025-01-21T10:45:03","modified_gmt":"2025-01-21T09:45:03","slug":"le-maregraphe","status":"publish","type":"post","link":"https:\/\/marseilleavantapres.fr\/index.php\/2024\/09\/17\/le-maregraphe\/","title":{"rendered":"Le Mar\u00e9graphe"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"384\" class=\"elementor elementor-384\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-60aa69f e-flex e-con-boxed e-con e-parent\" data-id=\"60aa69f\" data-element_type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-c3dd427 elementor-widget elementor-widget-image\" data-id=\"c3dd427\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"580\" height=\"414\" src=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/00_Maregraphe-photomontage.jpg\" class=\"attachment-large size-large wp-image-385\" alt=\"\" srcset=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/00_Maregraphe-photomontage.jpg 910w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/00_Maregraphe-photomontage-300x214.jpg 300w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/00_Maregraphe-photomontage-768x549.jpg 768w\" sizes=\"(max-width: 580px) 100vw, 580px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d18bd28 elementor-widget elementor-widget-text-editor\" data-id=\"d18bd28\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>\u267e\ufe0f Le mar\u00e9graphe de Marseille.<\/p><p>\ud83d\udccf Le mot \u201cmar\u00e9graphe\u201d d\u00e9signe \u00e0 la fois un appareil d\u2019enregistrement du niveau de la mer, et les b\u00e2timents qui abritent ce type d\u2019instrument. Le mar\u00e9graphe de Marseille a \u00e9t\u00e9 con\u00e7u pour fixer l\u2019origine des altitudes fran\u00e7aises continentales, soit l\u2019altitude 0. L\u2019altitude est mesur\u00e9e par \u201cnivellement de pr\u00e9cision\u201c.<\/p><p>\ud83c\udfd7\ufe0f Aux environs de 1860, un premier r\u00e9seau de nivellement national est cr\u00e9\u00e9 et son origine, \u201cle z\u00e9ro Bourdalou\u00eb\u201d, est choisi comme \u00e9tant le niveau moyen de la mer mesur\u00e9 \u00e0 Marseille pr\u00e8s du fort Saint-Jean. Ce niveau moyen un peu empirique est choisi car les mesures de l\u2019\u00e9poque indiquent qu\u2019il est le plus bas de tous ceux des ports fran\u00e7ais.<\/p><p>\ud83e\uddfe Une vingtaine d\u2019ann\u00e9es plus tard, dans le cadre d\u2019un plan de grands travaux, la Commission centrale du nivellement g\u00e9n\u00e9ral de la France a besoin d\u2019\u00e9tablir plus scientifiquement cette origine. Pour cela, elle d\u00e9cide de la construction du mar\u00e9graphe de Marseille. Il entre en service en 1885. Il est constitu\u00e9 d\u2019un b\u00e2timent pour abriter les appareils de mesure et d\u2019une maison pour son gardien.<\/p><p>\ud83c\udf0a \ud83c\udf0aLe mar\u00e9graphe rev\u00eat un int\u00e9r\u00eat scientifique majeur en contribuant au suivi, \u00e0 la compr\u00e9hension et \u00e0 la pr\u00e9vision de l\u2019acc\u00e9l\u00e9ration continue de l\u2019\u00e9l\u00e9vation du niveau de la mer, dont la cause est le changement climatique. L\u2019association Les Amis du Mar\u00e9graphe de Marseille a \u00e9t\u00e9 cr\u00e9\u00e9e pour faire conna\u00eetre l\u2019int\u00e9r\u00eat sp\u00e9cifique et remarquable de ce tr\u00e9sor scientifique. L\u2019un de ses objectifs en 2024 est d\u2019ouvrir plus largement le site au public, notamment aux scolaires. <a href=\"https:\/\/amis-maregraphe-marseille.fr\/\" target=\"_blank\" rel=\"noopener\">D\u00e9couvrez l&rsquo;histoire du lieu et son actualit\u00e9 sur le site internet de l&rsquo;association<\/a>.<\/p><p>\ud83d\udcf8 Source du texte et des images : Les Amis du Mar\u00e9graphe de Marseille.<\/p><p>\ud83d\udd8b Initialement publi\u00e9 sur Instagram le 27 f\u00e9vrier 2024<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-4213bd2 e-flex e-con-boxed e-con e-parent\" data-id=\"4213bd2\" data-element_type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-699d037 elementor-widget elementor-widget-qi_addons_for_elementor_before_after\" data-id=\"699d037\" data-element_type=\"widget\" data-widget_type=\"qi_addons_for_elementor_before_after.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<div class=\"qodef-shortcode qodef-m  qodef-qi-before-after qodef--horizontal\">\n\t<div class=\"qodef-before-after-image-holder qodef-m-image\" data-offset=\"50\">\n\t\t<img decoding=\"async\" width=\"910\" height=\"650\" src=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/01_Maregraphe-avant.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/01_Maregraphe-avant.jpg 910w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/01_Maregraphe-avant-300x214.jpg 300w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/01_Maregraphe-avant-768x549.jpg 768w\" sizes=\"(max-width: 910px) 100vw, 910px\" \/><img decoding=\"async\" width=\"910\" height=\"650\" src=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/02_Maregraphe-apres.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/02_Maregraphe-apres.jpg 910w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/02_Maregraphe-apres-300x214.jpg 300w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/02_Maregraphe-apres-768x549.jpg 768w\" sizes=\"(max-width: 910px) 100vw, 910px\" \/>\t<\/div>\n\t\t\t<div class=\"qodef-handle-text\">\n\t\t\tGlisser\t\t<\/div>\n\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-eba189d e-flex e-con-boxed e-con e-parent\" data-id=\"eba189d\" data-element_type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-f4852c9 elementor-widget elementor-widget-qi_addons_for_elementor_before_after\" data-id=\"f4852c9\" data-element_type=\"widget\" data-widget_type=\"qi_addons_for_elementor_before_after.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<div class=\"qodef-shortcode qodef-m  qodef-qi-before-after qodef--horizontal\">\n\t<div class=\"qodef-before-after-image-holder qodef-m-image\" data-offset=\"50\">\n\t\t<img loading=\"lazy\" decoding=\"async\" width=\"910\" height=\"650\" src=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/03_Maregraphe-avant.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/03_Maregraphe-avant.jpg 910w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/03_Maregraphe-avant-300x214.jpg 300w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/03_Maregraphe-avant-768x549.jpg 768w\" sizes=\"(max-width: 910px) 100vw, 910px\" \/><img loading=\"lazy\" decoding=\"async\" width=\"910\" height=\"650\" src=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/04_Maregraphe-apres.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/04_Maregraphe-apres.jpg 910w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/04_Maregraphe-apres-300x214.jpg 300w, https:\/\/marseilleavantapres.fr\/wp-content\/uploads\/2024\/09\/04_Maregraphe-apres-768x549.jpg 768w\" sizes=\"(max-width: 910px) 100vw, 910px\" \/>\t<\/div>\n\t\t\t<div class=\"qodef-handle-text\">\n\t\t\tGlisser\t\t<\/div>\n\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>\u267e\ufe0f Le mar\u00e9graphe de Marseille. \ud83d\udccf Le mot \u201cmar\u00e9graphe\u201d d\u00e9signe \u00e0 la fois un appareil d\u2019enregistrement du niveau de la mer, et les b\u00e2timents qui abritent ce type d\u2019instrument. Le mar\u00e9graphe de Marseille a \u00e9t\u00e9 con\u00e7u pour fixer l\u2019origine des altitudes fran\u00e7aises continentales, soit l\u2019altitude 0. L\u2019altitude est mesur\u00e9e par \u201cnivellement de pr\u00e9cision\u201c. \ud83c\udfd7\ufe0f Aux [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":385,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[5],"class_list":["post-384","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-avant-apres","tag-avant-apres"],"_links":{"self":[{"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/posts\/384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/comments?post=384"}],"version-history":[{"count":13,"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/posts\/384\/revisions"}],"predecessor-version":[{"id":450,"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/posts\/384\/revisions\/450"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/media\/385"}],"wp:attachment":[{"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/media?parent=384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/categories?post=384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/marseilleavantapres.fr\/index.php\/wp-json\/wp\/v2\/tags?post=384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}