http://stravaiger.com/blog/tags/index-contours/ Recent content in Index Contours on eBothy Blog Hugo en-us Sun, 06 Dec 2009 00:00:00 +0000 http://stravaiger.com/blog/2009/12/06/working-out-the-slope-angle-the-hard-way/ Sun, 06 Dec 2009 00:00:00 +0000 http://stravaiger.com/blog/2009/12/06/working-out-the-slope-angle-the-hard-way/ <p>I was idly browsing January&rsquo;s <a title="TGO" href="http://www.tgomagazine.co.uk/">TGO</a>, yes it&rsquo;s only December but the mag is a month ahead and alongside the usual excellent content, there was an article on winter navigation. Now, as I&rsquo;m heading for Winter ML assessment next winter (consolidation this winter), I took note of some points, especially the bit where it said that 6 index contours in 1cm on a 1:50,000 map is a slope angle of 30deg. That&rsquo;s the most common angle for big avalanches, so it helps to be able to spot one on the map when you&rsquo;re planning your day out in the winter mountains. Where does that number come from though? Well, with the rain lashing the windows and the gale rattling the slates (bit wild at the eBothy today), I thought I&rsquo;d brush up some ancient maths skills to find out.</p> <p><a href="http://stravaiger.com/blog/images/posts/working_out_the_slope_angle_the_hard_way/working_out_the_slope_angle-4163231760.jpg" title="Working out the slope angle"><img src="http://stravaiger.com/blog/images/posts/working_out_the_slope_angle_the_hard_way/working_out_the_slope_angle-4163231760-800px.jpg" alt="Working out the slope angle"></a></p>