Before the days of global positioning satellites, the Ordnance Survey used triangulation stations to aid in mapping the UK. Surprisingly there are active groups of trig spotters who visit as many of these as they can and tick them off. A quick search on the internet throws up several of their websites. A curious pastime I suppose but nevertheless a healthy one since getting to these concrete pillars keeps a person reasonably fit. For me they’re the culmination of a (mostly) enjoyable walk up a hill as well as a handy waist-height flattish surface for the cheese rolls, hot water flask and mug of cuppasoup!
Barely visible from the moor road over to Penicuik from West Linton, this trig point below on Auchencorth Moss is in danger of being lost as the peat extraction works expand.