Mapping Mountains – Trimble Surveys – Mynydd Epynt

18.05.25  Pen y Crug (SO 029 303) 

Pen y Crug (SO 029 303)

Hill celebrations are always wonderful occasions.  They are culminations of what for many people are years of ticking off hills in a list.  They are also occasions when old and new friends meet, and if combined with beautiful weather, as today was, they can be a shear joy to experience.

Today was the finish of Mark Trengove’s Welsh Hump completion.  For the uninitiated, a Hump is a 100m prominence hill.  There are 368 qualifying Welsh hills that meet this criterion and the one Mark had singled out for his last was Pen y Crug, which connects with the Mynydd Epynt group of hills.  Although much of this hill range is out of bounds due to a military training area, Pen y Crug is positioned on the southern periphery and well away from any out of bounds land.

I had been up the hill once before, in September 2017, when Lou and I ascended from the south-east on a good track that turned to a friendly green path leading up through the autumnal colour to the trig pillar that sits atop the summit.  On this day the tops of the higher Beacons were just skimmed with cloud, otherwise the hill gave excellent views.  Today the sky was an unadulterated blue with skylarks singing above and a welcome slight breeze cooling proceedings.  It was a perfect day for a hill celebration.

Mark drove from Mold to Welshpool, from where I then drove south to the car park at the base of the hill to its north.  This was close to its bwlch and gave me a chance to experience the hill from a different perspective and approach, which I always enjoy.

Our meeting time was midday and we arrived with 20 minutes to spare.  Soon cars started to appear, Rick and Jenny, Brent Lynam, Alex Cameron and Tony Jenkins soon arrived, followed by Barry Smith, Chris Bienkowski, Adrian Rayner and Keith Anderson.  It was good to see all, many who I had not seen for quite sometime.

I made an excuse to wander off to take a few photos of the hill, and asked Mark to keep everyone at bay for a few minutes; this gave me opportunity to head in to an adjacent field to get a few photographs, but also gave opportunity to gain a few minutes on everyone else and sneak away for a leisurely plod up the path leading to the open hillside above.

It felt good to be out in the sunshine, slowly wandering taking in the surrounds with skylarks singing, bees buzzing and bluebells and greenery all around, and all with the backdrop of the blue sky.  The path led up with greened hedgerows either side and manicured grazed fields beyond.  The enclosed path gave views directly toward the higher hill, which loomed above in a gently curved profile.

The path led to a gate which gave access to the open upper hill, from where an earthen dried path contoured up giving extended views past hillsides of bluebells to the light grayed ridges of the Black Mountains away to the east. 

The view east toward the Black Mountains

My pace was leisurely and all too soon I was caught by the throng of people following.  We soon crested the ridge that affords views south toward the higher Beacons.  Beyond the greened path led toward the ancient embankment and ditches that encircle the upper hill. 

I was soon caught up

Arriving at the summit we waited for Mark, who sauntered up behind us.  As he approached the high point there was a guard of honour waiting for him, with raised walking poles leading him over the summit of the hill toward the trig pillar.  He’d completed the Welsh Humps.  

Mark approaching the summit of Pen y Crug

All hill lists can take you on a journey to places that otherwise you would not visit; this is part of their appeal.  There is of course the small bonus that hills can afford tremendous experience and I’m sure the Welsh Humps have given Mark some excellent days on the hill. 

The guard of honour leading Mark to the summit

The next hour was one of those special occasions on the hill, with lots of conversation small glasses of Welsh whiskey, cake, strawberries and lots of nibbles and photos. 

Mark celebrating his completion of the Welsh Humps

During our time on the summit someone mentioned that Pen y Crug was also Adrian’s 7,000 Tump.  Another remarkable achievement and soon Adrian was beside the trig pillar kindly posing for a few photos.  He had kept this quiet, allowing for Mark’s celebration. 

Adrian at the summit of his 7,000th Tump

After we had finished off much of the celebratory food and drink things started to be packed away and as we waved Rick and Jen off down the hill, the rest of us followed ten minutes or so afterward. 

A nice touch brought by Mark for cake adornment

Leaving the summit we headed north down the upper part of the hill until connecting with the earthen ramparts, and then followed these around the hill, before connecting with our inward route and following this back down through the heat of the afternoon to the awaiting cars below. 

At the summit of Pen y Crug, from left to right we have; Bryher, Rick, Jenny, Barry, Alex, Keith, Adrian, Tony, Brent, Chris and Mark

It had been an excellent time on the hill and was rounded off with a visit to a pub on the outskirts of Brecon for a good meal and more interesting conversation. 

 

Survey Result:

 

Pen y Crug 

Summit Height:  331.2m (converted to OSGM15) (previous Trimble GeoXH 6000 survey)  

Summit Grid Reference:  SO 02927 30312 (previous Trimble GeoXH 6000 survey)

Bwlch Height:  219.9m (LIDAR)

Bwlch Grid Reference:  SO 02162 30880 (LIDAR) 

Drop:  111.4m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  33.62% (Trimble GeoXH 6000 summit and LIDAR bwlch) (Lesser Dominant addition)

 

 

For details on the summit survey of Pen y Crug

For further details please consult the Trimble Survey Spreadsheet 

Mapping Mountains – Hill Reclassifications – Y Trechol – The Dominant Hills of Wales

Pen y Crug (SO 029 303) – Lesser Dominant addition

There has been an addition to the list of the Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from a Trimble GeoXH 6000 survey and LIDAR analysis conducted by Myrddyn Phillips. 

Pen y Crug (SO 029 303)

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

Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence  equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Pen y Crug, and it is adjoined to the Mynydd Epynt group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north and south-west, the B4520 road to its north-east and the A40 road farther to its south, and has the town of Aberhonddu (Brecon) towards the south-east.

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 331m summit height, based on the spot height adjoined to a triangulation pillar that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 108m of drop, based on the 331m summit spot height and an estimated c 223m bwlch height, based on interpolation of 10m contouring between 220m – 230m, resulting in a dominance value of 32.63%, which was insufficient for Lesser Dominant status. 

The Trimble GeoXH 6000 gathering data at the summit of Pen y Crug

The summit of the hill was subsequently surveyed with the Trimble GeoXH 6000, resulting in a 331.2m height, which when combined with the amended bwlch height of an estimated c 222m, based on interpolation of 5m contouring then available on the OS Maps website, gave an estimated c 109m drop and 32.97% dominance value, which was still too low for Lesser Dominant status. 

LIDAR image of Pen y Crug (SO 029 303)

However, it was not until LIDAR became available that the bwlch 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. 

LIDAR bwlch image of Pen y Crug

Therefore, the addition of this hill to Lesser Dominant status is due to a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis, resulting in a 331.2m summit height and a 219.9m bwlch height, with these values giving this hill 111.4m of drop and 33.62% dominance, which is sufficient for Lesser Dominant status. 

 

The full details for the hill are:

Group:  Mynydd Epynt

Name:  Pen y Crug

OS 1:50,000 map:  160

Summit Height:  331.2m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 02927 30312 (Trimble GeoXH 6000)

Bwlch Height:  219.9m (LIDAR)

Bwlch Grid Reference:  SO 02162 30880 (LIDAR)

Drop:  111.4m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  33.62% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

Myrddyn Phillips (March 2024)

 

  

Mapping Mountains – Trimble Surveys – Mynydd Epynt

23.09.17  Pen y Crug (SO 029 303)

Pen y Crug (SO 029 303)

Pen y Crug overlooks Aberhonddu (Brecon) with the town nestling against the Afon Wysg (River Usk) as it ebbs forever eastward.  The hill is crowned by a triangulation pillar and the remains of an impressive Iron Age hill fort and gives expansive views to the higher southward hills.

Although passing close to Aberhonddu on many an occasion I’d never stopped to visit Pen-y-crug, and with a planned lunchtime meal and wander round Hay, Lou and I thought taking in a small hill ideal to add to the day’s activities.

We approached from the south-east following a bridleway consisting in part of tarmac and concrete as it headed up beside enclosed hedgerows toward the last inhabited house or two before open hillside gave access to the upper part of the hill.

Heading up the path toward Pen y Crug

Driving west from Worcester the weather had proved a murky combination of grey low mist and persistent drizzle, not an ideal combination for a hill walk, but a slight brightness pervaded the land further west and as we walked up the bridleway the cloud base had risen and the rain had thankfully stopped.

The enclosed nature of the lower part of the walk was in contrast to the upper part of the hill as a greened path led beside coloured autumnal bracken through the hill’s old defensive ditches toward the summit.

The view south-east down the path we'd just come up

Glimmers of brightness slowly showed as we approached the trig pillar, whilst Lou headed off to admire the view I set the Trimble atop my rucksack and activated it to gather the allotted 300 datum points and five minutes of data.

Lou with Aberhonddu (Brecon) nestled in the valley below

The summit consists of closely cropped grass that wouldn’t be out of place on the putting green of a golf course, with the high point about five metres from the base of the trig pillar which is enclosed in stone with its upper part painted white and festooned in a red dragon motif.

Gathering data at the summit of Pen y Crug

Once data were stored and the Trimble closed off and packed away we retraced our inward route back down the hill where sunshine and warmth greeted us.

Survey Result:

Pen y Crug 

Summit Height:  331.2m (converted to OSGM15) (Trimble GeoXH 6000)   

Summit Grid Reference:  SO 02927 30312 (Trimble GeoXH 6000)

Bwlch Height:  219.9m (LIDAR)

Bwlch Grid Reference:  SO 02162 30880 (LIDAR)

Drop:  111.4m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  33.62% (Trimble GeoXH 6000 summit and LIDAR bwlch) 

(Lesser Dominant addition)

For details on the 2nd visit to Pen y Crug

For further details please consult the Trimble Survey Spreadsheet