Mapping Mountains – Hill Reclassifications – The Welsh P15s

 

Pt. 357.3m (SN 995 612) – Welsh P15 reclassified to Welsh Sub-P15 

There has been a reclassification to the list of The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pt. 357.3m (SN 995 612)

The criteria for the list that this reclassification applies to are:

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The hill is being listed by the point (Pt. 357.3m) notation as an appropriate name for it either through local enquiry and/or historic research has not been found by the author, and it is adjoined to the Drygarn Fawr group of hills, which are situated in the central part of the South Wales Region (Region B, Sub-Region B1), and it is positioned with a minor road to its immediate west and the A470 road to its north-east, and has the town of Llandrindod Wells towards the east.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with 15m of drop, based on the 358m summit spot height and the 343m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the reclassification of this hill to Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 357.3m summit height and a 342.9m bwlch height, with these values giving this hill 14.4m of drop, which is insufficient for it to be included in the main list of The Welsh P15s. 

 

The full details for the hill are: 

Group:  Drygarn Fawr 

Name:  Pt. 357.3m 

OS 1:50,000 map:  147

Summit Height:  357.3m (LIDAR)                                                           

Summit Grid Reference:  SN 99517 61281 (LIDAR) 

Bwlch Height:  342.9m (LIDAR) 

Bwlch Grid Reference:  SN 99418 61379 (LIDAR) 

Drop:  14.4m (LIDAR) 

 

Myrddyn Phillips (January 2023)

 

 

 

 

Mapping Mountains – Trimble Surveys – Drygarn Fawr

 

27.11.22  Pt. 357.3m (SN 995 612) 

November days are to be treasured.  The first frosts linger in chilled mornings with mist enshrouded valleys heralding the near onset of winter.  But November days also give dulled grey skies with misted hill tops.  Usually the latter have hardly a breath of breeze adding a quiet tranquillity to an otherwise dulled scene.  It was such a day today, with the land quiet and autumnal colour still clinging on. 

A grey November day

A walk was planned, more a meeting of good friends with a small hill as accompaniment.  We had an added bonus to find, but this post will concentrate on the hill, which although only having a small amount of prominence gave a good ascent when approaching from its south-east.

I was out with Darrin and Lisa, and Eryl and Rita; as it was Lisa’s birthday celebratory nibbles were also had during the walk.  We met in Trefeglwys before continuing to Llanidloes and then driving southward toward Newbridge on Wye, followed by the minor roads leading to our designated parking spot. 

Heading eastward toward the old house

Although the skies were leaden and dull looking as if they were going to be awash with rain, the forecast gave for dry and brightening conditions.  Even though we were in no rush, the walk only took two hours; leaving the cars for a leisurely stroll across a steep field heading eastward.  This would take us on a circuitous route around the upper part of our small prominence hill before striking upward toward its summit.

Prior to visiting this hill I had examined its numerical data via LIDAR.  Therefore, although tempted to bring the Trimble to at least take a summit data set, I decided to leave this at home and be reliant upon the highly accurate LIDAR summit and bwlch data for its height and position. 

LIDAR image of Pt. 357.3m (SN 995 612)

We had two stops before the summit, one at an old house and the other sitting on rocks in the adjacent field to the summit for chats and nibbles.  Before joining the group at this latter spot I sauntered over to a small pool that was probably only there because of recent rain.  From here I spent a number of minutes admiring the reflection of old trees in the water whilst my friends opened the nibbles. 

Reflected view before celebratory nibbles

After our stop it was only a short distance to the summit, with increasingly good views in all directions, with the bulk of Drum Ddu ahead and the river valley below.  Between the two were moorland ridges and more hills.  It felt good to be out. 

Heading toward the summit of the low prominence hill

Leaving the summit we made our way down to the minor road and from here it was only a short walk back to the cars, with two highly enjoyably leisurely hours on the hill, an excellent way to spend a day. 

 

Survey Result:

 

Pt. 357.3m

Summit Height:  357.3m (LIDAR)

Summit Grid Reference:  SN 99517 61281 (LIDAR)

Bwlch Height:  342.9m (LIDAR)

Bwlch Grid Reference:  SN 99418 61379 LIDAR)

Drop:  14.4m (LIDAR) (Welsh P15 reclassified to Welsh Sub-P15)

Dominance:  4.02% (LIDAR)

 

 

For further details please consult the Trimble Survey Spreadsheet