Searching for a trig point

Spencer Codford Fort trig point We have some real characters working here at Dennis Maps. We’re passionate about map printing, as you may have read in our recent interview with Keith Vranch, who’s been a printer since the 1970’s. Christian Coates is a CTP Operator and has a very unusual hobby – he’s mad about trig points! We asked him to share his trig point enthusiasm.

What is a trig point?

Trig points are fixed surveying stations that were built by Ordnance Survey to map the contours of the land. They are also known as a triangulation station or pillar, a trigonometrical station or point, a trig station or beacon…or just a trig!

They are usually a concrete or stone pyramid or obelisk. On the top is a brass plate with three arms and a central depression that was used to mount and centre a theodolite, to take angular measurements to neighbouring trig points.

Trig stations are grouped together to form a network of triangulation. They were an early form of GPS and although trig points are no longer required for surveying purposes, they remain useful to hikers as navigational aids.

The use of trig points stopped in the 1960’s as the use of satellites, planes and drones rendered them obsolete. Some have been removed by farmers and land owners.

How to spot one on a map

Ben Nevis In Winter triangulation pillarTrig points are shown on OS maps as a small blue triangle, called a triangulation pillar. There are over 6500 in the UK, and only one person is known to have done them all.

I’ve done about 30 so far, so I have a long way to go to catch that person up! Working at Dennis Maps means that I am surrounded by maps all day, so when the machine is running on a long job, I can pull a map out and search for a new trig point.

All my personal maps have circles drawn on them, showing where the trig points are. When I find a few on the map, I circle them all and plot a route. They go almost unnoticed on the map as they are so small and I quite like that – it makes them a challenge to find.

I only use paper OS maps, never apps. I have very good map reading and compass skills because my dad taught me the importance of knowing how to read a map.

How did you get started on your trig collection?

Father Hellvellyn trig pointIt was my father who got me interested in them, too. We went to Mount Helvellyn, the third highest mountain in England, and found a trig point quite by accident. After that I wanted to find more.

I always have my walking boots in the car, so I will leave work at 2pm and set off to find one or two.

They are always at high points, and typically, when I find one, I stand on it to get the best view. Some are absolutely spectacular, while others are a little disappointing as the hedges have grown over them.

Do you have a rare or ‘holy grail’ points that you would like to see?

My ‘holy grail’ trig points were the Three Peaks – Scafell Pike, the highest mountain in England, Ben Nevis, the highest mountain in Scotland, and Snowdon, the highest mountain in Wales. The next trig point I am desperate to complete is Steep Holm Island.

It’s in the Bristol Channel and lies about six miles off shore. The island is a bird sanctuary and boat trips are organised when the weather allows, so it’s definitely on my ‘to do’ list. Hopefully for this summer when the water is calm.

I mainly do trig points solo, but my children like to search for them as well. When they find one on a map, we plan a route together, so it makes it a family activity, with the bonus of getting us all outside.

Do you have any favourites so far?

Chase Cold Kitchen Hill triangulation pointI would say it’s probably Cold Kitchen Hill, near Warminster in Wiltshire. I completed this one with my son, Chase. It was amazing weather, there were gliders in the sky and the view from the top was perfect. We just had a great time.

It’s a niche hobby, and I can’t see it catching on too much. People are intrigued by trig points and by maps in general, but most people don’t have a reason to pick up a map these days, which is a shame as the detail in them is absolutely amazing. I see something different each time I look at a map.

In this age of computer games, it’s great just to be able to get outside with the children and go hunting for trig points that were used to map the land long before we were born.

Do you know what the OS map symbol is for trig points? See here for the trig point and other OS symbols.

Other posts by Christian Coates:

What’s so Great About Doing a Triathlon?

Road Cycling Maps


Please share