{"id":639,"date":"2024-07-03T10:24:59","date_gmt":"2024-07-03T10:24:59","guid":{"rendered":"https:\/\/study.madeeasy.in\/?p=639"},"modified":"2025-07-16T14:54:13","modified_gmt":"2025-07-16T09:24:13","slug":"magnetic-declination","status":"publish","type":"post","link":"https:\/\/www.madeeasy.in\/study\/ce\/surveying\/magnetic-declination","title":{"rendered":"MAGNETIC DECLINATION"},"content":{"rendered":"\r\n<ul>\r\n<li>It is quite a common phenomenon that the magnetic meridian and the true meridian at a place generally do not coincide.<\/li>\r\n<li>The horizontal angle which the magnetic meridian makes with the true meridian is called as magnetic declination (also sometimes referred to as declination).<\/li>\r\n<\/ul>\r\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-387 aligncenter\" src=\"http:\/\/study.madeeasy.in\/wp-content\/uploads\/2024\/07\/magnetic-declination.jpg\" alt=\"Magnetic declination\" width=\"497\" height=\"205\" \/><\/p>\r\n<ul>\r\n<li><strong>Negative declination:<\/strong> When magnetic north lies towards the west of true north, then the declination is said to be negative.<\/li>\r\n<li><strong>Positive declination:<\/strong> If the magnetic north lies towards the east of true north, then declination is said to be positive.<\/li>\r\n<li>The magnetic declination at a place can be measured in the field by establishing the true meridian by astronomical observations followed by determination of magnetic bearing of the line.<\/li>\r\n<\/ul>\r\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_79_1 ez-toc-wrap-left counter-hierarchy ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.madeeasy.in\/study\/ce\/surveying\/magnetic-declination\/#Isogonic-lines\" >Isogonic lines<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.madeeasy.in\/study\/ce\/surveying\/magnetic-declination\/#Agonic-lines\" >Agonic lines<\/a><\/li><\/ul><\/nav><\/div>\n<h3><span class=\"ez-toc-section\" id=\"Isogonic-lines\"><\/span>Isogonic lines<span class=\"ez-toc-section-end\"><\/span><\/h3>\r\n<p style=\"text-align: justify;\">Declination varies from place to place and also from time to time at the same place. This variation of declination at different places is studied with the help of isogonic lines which are the lines passing through the points on earth\u2019s surface having the same declination at a particular time. Now the earth\u2019s magnetic field is not uniform and thus isogonic lines do not form the complete great circles. These lines radiate from the north and south poles of the earth and then follow irregular paths.<\/p>\r\n<h3><span class=\"ez-toc-section\" id=\"Agonic-lines\"><\/span>Agonic lines<span class=\"ez-toc-section-end\"><\/span><\/h3>\r\n<p style=\"text-align: justify;\">A special case of isogonic lines are the agonic lines which represents the isogonic lines with zero declination. Thus at all the points on agonic lines, the true meridian and the magnetic meridian coincide.<\/p>\r\n\r\n\r\n\r\n<p style=\"text-align: center;\"><a class=\"btn btn-danger\" role=\"button\" href=\"https:\/\/study.madeeasy.in\/ce\/surveying\/fore-bearing-and-back-bearing\/\" target=\"_blank\" rel=\"noopener\">&lt;&lt; Previous<\/a> | <a class=\"btn btn-success\" role=\"button\" href=\"https:\/\/study.madeeasy.in\/ce\/surveying\/true-bearing-from-the-magnetic-bearing\/\" target=\"_blank\" rel=\"noopener\"> Next &gt;&gt;<\/a> <br \/><strong> Must Read: <\/strong> <a href=\"https:\/\/study.madeeasy.in\/subjects\/what-is-surveying\/\" target=\"_blank\" rel=\"noopener\"><strong>What is Surveying?<\/strong><\/a><\/p>\r\n<p>&nbsp;<\/p>\r\n","protected":false},"excerpt":{"rendered":"<p>It is quite a common phenomenon that the magnetic meridian and the true meridian at a place generally do not<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[203,2],"tags":[217,218,219],"class_list":["post-639","post","type-post","status-publish","format-standard","hentry","category-surveying","category-ce","tag-agonic-lines","tag-isogonic-lines","tag-positive-declination"],"_links":{"self":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts\/639","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/comments?post=639"}],"version-history":[{"count":0,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts\/639\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/media?parent=639"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/categories?post=639"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/tags?post=639"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}