Mapping Mountains – Significant Name Changes – 100m Twmpau and Y Trechol - The Dominant Hills of Wales

Coed Pant y Glo (SH 767 014)

There has been a Significant Name Change to a hill that is listed in the 100m Twmpau and Y Trechol - The Dominant Hills of Wales, with the hill’s summit height and drop being confirmed by a survey with the Trimble GeoXH 6000 which took place on the 29^th October 2017 and subsequent LIDAR analysis conducted by Myrddyn Phillips.

The criteria for the two lists that this name change applies to are:

100m Twmpau – All Welsh hills at and above 100m and below 200m in height that have 30m minimum drop, with the word Twmpau being an acronym for ‘thirty welsh metre prominences and upward’.

Y Trechol – The Dominant Hills of Wales – All Welsh P30 hills whose prominence equal or exceed half that of their absolute height.

The hill is adjoined to the Pumlumon range, this group of hills are situated in the north-western part of Mid and West Wales (Region B, Sub-Region B2), and the hill is positioned overlooking the A 489 road to its south and the Afon Dyfi to its north, with the town of Machynlleth towards the west. 

Coed Pant y Glo (SH 767 014)

The hill appeared in the 100m P30 list on Geoff Crowder’s v-g.me website under the name of Bryntudor, with an accompanying note stating; Name from buildings to the North-East.  During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them or as in this instance, just use the name of a house situated close to the summit of the hill.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historical documents, through this form of research an appropriate name for the hill can usually be found, and in the case of this hill an appropriate name for it appears on contemporary as well as historical Ordnance Survey maps.

Bryntudor

141m

SH768014

135

23/215

Name from buildings to the North-East

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey maps made available online, some of these are historical such as the series of Six-Inch maps on the National Library of Scotland website, whilst others are current and digitally updated such as the enlarged map on the Geograph website, and it is the series of Six-Inch maps that give the name of the wood where the summit of this hill is situated as Coed Pant y Glo.  This name also appears on the contemporary Ordnance Survey 1:25,000 Explorer map.

Extract from the Ordnance Survey Six-Inch map

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

Therefore, the name this hill is now listed by is Coed Pant y Glo and this was derived from the series of Ordnance Survey Six-Inch maps as well as the contemporary 1:25,000 Explorer map.

The full details for the hill are:

Group:  Pumlumon

Name:  Coed Pant y Glo

Previously Listed Name:  Bryntudor 

OS 1:50,000 map:  135

Summit Height:  140.7m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 76776 01435 (Trimble GeoXH 6000) 

 

Bwlch Height:  49.05m (LIDAR)

Bwlch Grid Reference:  SH 77889 01169 (LIDAR)

Drop:  91.7m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  65.15% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For details on the survey of Coed Pant y Glo

Myrddyn Phillips (January 2018)

Mapping Mountains – Trimble Surveys – Pumlumon

29.10.17  Coed Pant y Glo (SH 767 014)

Coed Pant y Glo (SH 767 014)

Coed Pant y Glo nestles in to its landscape; almost forgotten it overlooks the flat bedded land of the Dyffryn Dyfi to its north and the A 489 road leading toward Machynlleth to its south.  Its summit is just within the wood where the hill takes its name from, with a number of near and attractive tops outside of this wood and all of which are lower.

I approached from the south-east following a public footpath beyond the grounds of Gallt-y-llan; a substantial house at the end of the paved road.  As I clambered up beside a garage and over a rusted low gate the afternoon’s sunshine added warmth to proceedings.

The gate gave access to a steep brackened field where two further gates led toward the summit area of the hill.  Across the valley the summits of Copa Shon and Pen y Graig Fawr dominated, I’d just visited each and it felt good to look out toward them from a different perspective.

Before heading in to the deciduous wood I assessed the high point of land outside of the wood, deciding that the survey of this point could wait I ventured across to the boundary fence, stretched over it and stood on the high point of the hill.  The summit of this hill is easily found and consists of land a metre from the boundary fence, beyond which the ground drops steeply to the south.

I set the Trimble up on top of my rucksack to give it elevation above its immediate surrounds and measured the offset between its internal antenna and the summit of the hill at the base of the rucksack, once the file was created in the Trimble I stood back and hoped I would not have to wait long before the 0.1m accuracy level was attained before data should be logged.

Gathering data at the summit of Coed Pant y Glo

During this waiting process I savoured the wood and its trees and its moss and its peacefulness; nothing seemed to stir except for the occasional flutter of a bird.  Eventually I activated the Trimble and again stood back amongst the trees and waited until the allocated datum points were collected and stored, once this was done I closed the equipment down, took a few photos and headed back to the high point of ground outside of the wood.

Moss on tree

This outside of the wood high point was on a grassed mound, similar in nature to a number that sprang up on the summit area, I placed the Trimble on the ground and waited for 300 datum points to be collected and stored before closing the equipment down.

Gathering data at the high point of land outside of the wood, with the wooded summit in the background of this photo

Leaving the summit area of Coed Pant y Glo it was only a short walk back on my inward route toward my car, I then headed toward Gallt y Gog; a lower forested P30 directly above Machynlleth.  Afterward I surveyed the bwlch of each hill.

The bwlch of Coed Pant y Glo is positioned in a field beside a drainage ditch which has a land bridge spanning the ditch leading down from an access gate.  I parked a short distance away down the road at the entrance to a caravan park and soon found myself standing beside a stunted tree hedge next to a bungalow, having set the Trimble up at what I deemed to be the high point on the valley to valley traverse and which was beside the drainage ditch.

Gathering data at the first Trimble set-up position at the bwlch of Coed Pant y Glo

I spent the next five minutes standing beside the hedge waiting for the Trimble to gather its allotted data.  On the other side of the hedge were a greenhouse and the back garden of the bungalow. 

Before heading back to my car I took another data set from the land bridge that spans the small wet ditch, this I decided would be the critical bwlch of the hill.  As I did so I watched the lowering sun cast colour across the opposing land, I was now in shade which only enhanced the illuminated colour on show.

Gathering data at the second Trimble set-up position at the bwlch of Coed Pant y Glo

I’d taken eleven data sets during the day on three separate walks and had visited five P30s and been out surveying for eight hours, it had been another good day. 

   

   

Survey Result:

Coed Pant y Glo (significant name change)

Summit Height:  140.7m (converted to OSGM15, Trimble GeoXH 6000)  

Summit Grid Reference:  SH 76776 01435 (Trimble GeoXH 6000)

Bwlch Height:  49.05m (LIDAR)

Bwlch Grid Reference:  SH 77889 01169 (LIDAR)

Drop:  91.7m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  65.15% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble Survey Spreadsheet