Trig points 99 (Intro)

Tuesday 16th August 2022

A new project:

Visiting all 22 trig points on Sheet 99: Ordnance Survey 1:50 Landranger 99 (Northallerton and Ripon.)

For any readers from abroad not familiar with UK mapping see footnote below.

I have previously visited all trigs on OS Sheets: 91 96 97 98 and 103. The next sheet that is the least drive from home, is 99.The furthest east trigs will involve a two hour drive, but those  are mostly easily accessible and I can probably mop up three or four in one visit. As I move back west the terrain looks more interesting and I may take more time by incorporating each trig within a decent walk if that can be engineered from surrounding paths and tracks. There are only 22 on this sheet compared with 76 for example on Sheet 103 so this should be a more modest project.

Identifying the trigs is tedious. I enlarge the map on my computer screen so the kilometre squares are about 10cm across and then traverse west to east and back east to west examining each square and placing a mark.

Here is a typical trig as shown within the context of a kilometre square:

The green triangle is my marker. Each trig shows its height above sea level in metres. In the field I use the larger scale 1:25 map that shows field boundaries and more access information.

The green triangles are from my original survey. The reds were a tracking system to make sure I had them all on the spreadsheet which serves as my master tick list - see below.

At the moment there are no ascents but as they occur I put a number 1 in the column indicated and the number remaining is automatically calculated at the bottom. It's all a bit nerdy eh?

The attraction is to give me a focus and a project to keep my aged frame and my mind as agile as possible in my declining years, whilst providing a possible adventure as one heads into unfamiliar territory with a purpose, hopefully making interesting discoveries and finding possible problem solving challenges when one encounters trigs located on private or difficult to access land. I can also choose to make quick forays for easy ones close to roads or please myself by incorporating them in longer walks. There are around 6,500 trig points covering the UK so there is no way I am going to visit them all, so no pressure. Has anybody visited them all? CLICK (recommended.)

Here are two good ones from the Yorkshire Dales (OS Sheet 98 - Wensleydale and Upper Wharfedale)

The Three Peaks from Rye Loaf Hill

Littondale from Cosh trig

******************************

Trig point = triangulation point.

To make a map: draw an accurate measured baseline (say 10 miles) - not easy. Stick a trig point at each end. Identify a high point several miles away and stick another trig point on it. Then measure the  two sets of angles horizontal and perpendicular from each end trig to the new one. Draw the connecting lines and calculate the lengths of the other two sides of your triangle and then continue from that triangle to its neighbours using their sides as each new baseline. In the UK the trig points are usually standard concrete pillars about four feet high with a mounting plate for the measuring instruments embedded in the top. and their location is marked on each map. For more entertaining information visit THIS.  (recommended)

OS divide their mapping into convenient local sheets

************************************************************

Katie's art update

I am told she used mixed acrylic and poster paint - mmm?