Trig Point Bagging

Ever considered trig point bagging? There are 6557 trig points in the UK, or at least there were orginally, some no longer exist. Many people enjoy bagging trigs, but 6557 is rather a lot of trig points to bag, so why not shorten the list to something more manageable? There are a number of ways to do this, Here are a few suggestions.

Summit Trigs

It’s important to be aware that many trigs don’t mark summits. Although many were placed directly on summits, their purpose was not to mark the highest point, but instead to create a network of visible points to use as a basis for mapping the country. Therefore visibility from other trigs was the most important thing. Very often the highest point was visible from other points, but often it wasn’t, particularly if it needed to be seen from lower down, in which case trigs would be placed on crests instead (often near to the top, but not directly on it).

So if you were to filter the list of 6557 trigs to include only the ones that actually mark summits, you’d end up with a much shorter list. Does anyone know if such a list has ever been produced?

Of course, there is a grey area, depending how strictly you interpret the meaning of a “summit trig”. If by “summit” you mean the actual highest point, many trigs don’t qualify since they are not exactly on the top. A lot of summits are marked by cairns for example, and the trig is placed a few metres away. Garreg Lwyd is a good example of this.  In other cases the trig may appear to mark the summit on the map, but when you get there it turns out that it doesn’t. Arenig Fach for example has a trig and a cairn, and neither mark the summit, but you can’t tell that from the map. Most people probably assume that the trig does mark the summit though. Another trig commonly assumed to mark the top is on Waun Fach, yet there’s a higher point some distance away which is unmarked.

So if you want to be really strict about it, this would weed out a lot of apparent “summit” trigs, but if you’re not that strict you could include them, provided they are pretty close to the top. I guess you’d have to decide how close they’d need to be to qualify. For example, I’d probably include trigs that are fairly close to the summit, like Garreg Lwyd and Arenig Fawr, but I wouldn’t include the trig on Drygarn Fawr, which is 65m away from the summit cairn and is 4m lower. The trig on Fan Fawr definitely wouldn’t qualify, being 665m away from the summit!

Altitude Limits

A simpler way of shortening the list would be to set an altitude limit, like say 300m (1000ft) for example, and only bagging trigs above this altitude. This would weed out all the low level trigs and give you a much shorter and more practical list. If you set a limit of say 500m or 600m, you’d stay within the realm of high level hill walking, so you wouldn’t have to bother with all those farmland trigs.

Here’s a list of the number of trigs over certain altitudes:

Over 1000m - 37 trigs
Over 900m - 72 trigs
Over 800m - 137 trigs
Over 700m - 239 trigs
Over 600m - 392 trigs
Over 500m - 676 trigs
Over 400m - 1160 trigs
Over 300m - 1813 trigs

As you can see, the numbers of high altitude trigs are quite manageable.

Area Divisions

Another easy way to reduce the number of trigs is to limit yourself to certain geographical areas. So you could bag all the trigs in Wales or England, or just Snowdonia or the Lake District, or even specific counties.

Wild Trigs

An idea I quite like is only to bag trigs that are located on open ground (i.e. non-farmland, forestry or urban). Compiling such a list would take quite a bit of study. Studying aerial photographs would probably be the easiest way to do that. This would avoid access problems and ensure that all the trigs you visited were “wild”. Doing it this way would mean you wouldn’t need an altitude limit, yet you could still avoid farmland, forestry and urban areas.

Combinations

Finally, you could use any combination of the above suggestions. For example you could bag all Summit trigs in England over 300m. Or the idea I like best, all Wild trigs in Wales! Maybe I’ll complile such a list one day…

So as you can see, there are plenty of ways to cut the list down to a manageable size and still provide yourself with a decent challenge.

There are a number of websites devoted to trig bagging, I think the most popular one is {TrigpointingUK}.

You can also download official {Ordnance Survey lists of all the trigpoints} from this website, compiled by John Davis. Note that the lists are avilable in two formats, OSGB and WGS84. OSGB is for use with maps, but the WGS84 list should be used with a GPS. There will be errors if you input the OSGB grid refs directly into a GPS.

Although these lists are in text format, they were produced with {GPS Utility}, so it’s best to use that in conjunction with a GPS. There’s a fully useable demo version availabe from the website, which can handle a limited number of waypoints.

This post was adapted from one I wrote earlier today on uk.rec.walking, in response to a question asked by Chris Fishwick.

Originally posted on my weblog on June 1, 2007

Comments

  1. {johnhee} | 3 June, 2007 at 5:59 pm

another trig point lover!

It will be a sad loss if these ever crumble away

  2. {Paul Saunders} | 5 June, 2007 at 10:36 pm

Well the word “lover” may be going a little too far, but I admit, they do make useful objectives for a walk, and they do have the advantage of having very precise grid refs available for them, which is great for testing the accuracy of GPS, a modern technology which is close to my heart!

At the end of the day, any walk needs an objective, and a trig point is as good as any! :-)