Hello! Thanks for sharing your idea.

I considered this when I was building the site but ultimately decided against it because I thought that it would clutter-up the guide with too many icons. (i.e. if there's an icon for mountain, should there also be one for gaps/notches/valleys or monuments or famous trees?) My approach then became: the feature types available should be the ones which are practical or will effect how someone plans their hike. So, for mountains, gaps, etc, I've always tagged those as either 'other' or 'view' (if there's a good view).