1.0OS Maps Discoverhttps://osmaps.com/discoverrich600338<blockquote class="wp-embedded-content" data-secret="Zj6ikQ8RB3"><a href="https://osmaps.com/discover/guides/advanced-contours-and-relief/">Advanced guide to reading contours and relief</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://osmaps.com/discover/guides/advanced-contours-and-relief/embed/#?secret=Zj6ikQ8RB3" width="600" height="338" title="“Advanced guide to reading contours and relief” — OS Maps Discover" data-secret="Zj6ikQ8RB3" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://osmaps.com/discover/wp-includes/js/wp-embed.min.js </script> https://getoutside-8ed4dca473-gkb9acgdcpe2fjhy.a01.azurefd.net/blobgetoutside5db8a681d3/wp-content/uploads/2024/03/advanced20contours20hero2.d635ad0f1f03d16ac80ae9884a3c9df0.jpg1920585Understanding contour lines and relief on a map is essential for safe planning and navigation across the varied terrain you may encounter on your outdoor adventures. This guide explain all you need to know about contours and help you read valley and ridge contour lines, slopes and spurs on an OS Map map.