Mapping Mountains – Trimble Surveys – Cefn yr Ystrad

06.06.23  Cefn y Brithdir (SO 120 043) 

LIDAR image of Cefn y Brithdir (SO 120 043)

I’m not sure what to say about this hill as we parked about 100 metres from its summit.

Cefn y Brithdir was my third Pedwar of the day and Mark’s fourth.  A minor road follows the course of its broad ridge, which is aligned north-west to south-east.  Prior to our visit I had read reports that the mountain road had recently been closed via a swing gate, which on recent visits by a number of hill baggers was locked, with fly tipping the probable reason for this.  Today, the swing gate was open and therefore we took full advantage and drove up as high as we could, eventually parking on the grass verge beside the minor road having turned around to face our route down which was ever northward.

Once out of the car Mark checked his GPS and declared that it was 83 metres to the top, just my kind of ascent!  I followed him as he strode out to conquer the summit of another Pedwar. 

LIDAR summit image of Cefn y Brithdir (SO 120 043)

Prior to visiting these hills,  I had analysed new Welsh LIDAR and noted the heights and ten figure grid references for each summit and bwlch on our mini bagging bonanza.  LIDAR gives the high point of Cefn y Brithdir about 100 metres from where its recognised summit is positioned.  However, LIDAR only gives this point as 9mm higher than the accepted summit position, with two points at the latter position of equal height and about 4 metres apart. 

Happy in the knowledge of having just conquered another Pedwar!

Once at the LIDAR summit we thought a point beside two upright telegraph poles to be slightly higher, therefore as Mark wandered off to the accepted summit position with car keys in hand I set the Trimble up to gather what proved to be the first of three summit data sets. 

Mark on his way to the accepted summit position

Gathering data at the first of three potential summit positions

The second data set was taken at the LIDAR summit position, which was beside or in a large outcrop of reed grass.  At this point Mark was already heading back to the car to laze in the front seat with a bite to eat as the proper business of hill bagging was still taking place, and that of course is the necessity to survey all potential summit positions. 

Gathering data at the second of three potential summit positions 

Once the second data set was taken I strolled over the more attractive accepted summit position which LIDAR gives as 9mm lower, and set about zeroing in to what I judged to be its high point.  This certainly looked higher and was by far the more attractive summit, although a visual comparison is never the best. 

Gathering data at the third of three potential summit positions

Once the third summit data set was taken I packed the equipment away and sauntered down the 100 metres or so back to the car and the patiently waiting Mark. 

 

Survey Result:

 

Cefn y Brithdir                          

Summit Height:  444.8m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 12037 04322 (Trimble GeoXH 6000)

Bwlch Height:  358.2m (LIDAR)

Bwlch Grid Reference:  SO 10819 06005 (LIDAR)

Drop:  86.5m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  19.46% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

  

Mapping Mountains – Trimble Surveys – Cefn yr Ystrad

 

06.06.23  Twyn yr Hyddod (SO 145 060) 

Twyn yr Hyddod (SO 145 060)

A day Pedwar bagging in the south Wales valleys with Mark, I started at a very leisurely pace with my head rested and eyes closed sitting in the front seat of my car whilst Mark visited the summit of Cadair Fawr (SN 977 123), a hill I had previously been up.  Although my eyes were closed for much of the time whilst I occasionally happily snoozed, I was still amazed at how fast cars seem to travel when passing a stationary object, they literally whizzed past on the minor road immediately in front of me as I opened an eye and stared out across a large expanse of grassland that disappeared toward the horizon with only the white flecks of a sheep or two to break the green monotony.

Once Mark was back from his first hill of the day he navigated us to the ridge above the Rhymni and Sirhywi valleys, it was here that the next two hills we planned on visiting were situated.  The first of which was Twyn yr Hyddod, which is a great bulk of a hill whose ascent is made easy if the convenience of its mountain road is taken, we took it, and I parked on the grass verge just below the high point of the road. 

Looking back toward the parking spot with the man-made hills of Twyn y Waun in the background on right

From the parking spot it was only a relatively short walk over copious amounts of bilberry up to the broad upper southerly ridge and then across to its crowning triangulation pillar.  However, before getting to the top I looked back beyond my car to the rows of terraced houses that make up the small community of Abertysswg, whose narrow road we had just driven on, on our way up the hill.  Beyond in the valley below were the houses of Rhymni and on the opposing side were the man-made hills of Twyn y Waun, which would be our last objective of the day. 

Approaching the summit of Twyn yr Hyddod

It was decidedly chilly on the ascent, so much so that when we reached the top Mark headed back down, leaving me to position the Trimble atop my rucksack and do all necessary things, such as noting the measurement offset between its internal antenna and the ground at its base and creating the file in the Trimble once the minimum of five satellites were logged on to.  All that remained was to wait until the 0.1m accuracy level was attained before data should be logged and then to stand back so as not to interfere with satellite reception whilst the allotted five minutes of data were gathered and stored.  During which I scribbled all necessary details in my surveying notebook. 

Gathering data at the summit of Twyn yr Hyddod

Once data were stored, I closed the equipment down, took a few photographs and packed it away and headed down, overshooting the direct descent which meant a slight double-back and a wander down the mountain road back to the car and the patiently waiting Mark, who was shielded from the chilled breeze whilst enjoying a bite to eat.  Twyn yr Hyddod proved a fine hill to start the day on. 

 

Survey Result:

 

Twyn yr Hyddod                       

Summit Height:  485.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 14515 06012 (Trimble GeoXH 6000)

Bwlch Height:  369.4m (LIDAR)

Bwlch Grid Reference:  SO 11880 10171 (LIDAR)

Drop:  116.2m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  23.93% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

Mapping Mountains – Trimble Surveys – Moel y Gamelin

16.09.21  Pt. 395.9m (SJ 215 543) 

Pt. 395.9m (SJ 215 543)

This hill is positioned in the Red Grouse Country Park and forms land associated with the Lake Hill Fishery with Llyn Cyfynwy providing the fishing.  The bulk of the hill consists of heather moor; however access is relatively easy, either from the convenience of the car park adjoined to the fishery café which is positioned just to the east of the summit or from a minor road to its north.  I chose the latter approach. 

Prior to visiting this hill I had a number of things to do in Oswestry and therefore my usual early morning start was delayed somewhat.  I drove north as morning cloud started to break and with a settled forecast for afternoon sunshine and light winds it was ideal for visiting hills and surveying. 

Driving through the small community of Rhydtalog, I then connected with the minor road heading westward to the north of this hill and parked close to a gate that gave access across two fields toward the heather moor. 

The summit cone of the hill rose heathered in the near distance, a dark silhouette when I approached toward the lake as late morning sun flickered behind cloud.  A second gate gave access to the good vehicle track, come path that circles the waters of Llyn Cyfynwy. 

Llyn Cyfynwy with the 395.9m heighted hill in the background

I wanted to walk around the lake and call at the fishery/café after visiting the summit to make place-name enquiries and therefore opted for the path on the westerly side of the lake for my ascent.  The path is good and took me to within easy striking distance of the hill’s high point which is crowned by a triangulation pillar. 

During the walk a continuous tata-tat-tat was emanating from the shooting range to the south of this hill.  The shooting range is adjoined to a 385m map heighted hill which I wanted to visit afterward and which is situated just to the south of the A5104 road which makes its way between these two hills. 

Approaching the summit

The last few metres to the summit was steeper than any on the approach and has a knotted rope in place, secured around the base of the trig for those wanting an aid to the high point.  As I stood beside the trig the firing range was in view, it was obviously popular as there were many cars parked there and any approach to the 385m map heighted hill from that direction would be off limits and potentially hazardous. 

The high point of my first hill of the day was easy to identify and consists of an embedded rock near the base of the trig pillar.  I secured the Trimble in place with the aid of its bag which I placed under one side of it, by doing so its internal antenna was aligned to the highest part of the summit rock and it was now neatly sitting in place, instead of at an angle. 

Gathering data at the summit of Pt. 395.9m

During data collection I kneeled behind the trig and scribbled all necessary detail in my surveying notebook.  After five minutes of data were gathered and stored I closed the equipment down, packed it away, took a few photographs and reversed my inward route back toward the lake and then headed on the path toward the fishery. 

Pt. 395.9m from near the shore of Llyn Cyfynwy

At the cabin close to the café I called out my ‘hello’s’ and the owner then emerged.  We talked for five minutes or so, he told me he just refers to the hill as trig point and didn’t know of a name for it.  I thanked him for his time and continued on the path around the eastern side of the lake.  It was only a short distance back to my car.  This hill was an ideal first walk of the day, and I hoped to do another two or three before heading home before a section of the A483 road was closed off in the evening. 

 

Survey Result:

 

Pt. 395.9m (significant name change)

Summit Height:  395.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 21508 54329 (Trimble GeoXH 6000)

Bwlch Height:  c 341m (interpolation)

Bwlch Grid Reference:  SJ 22252 54249 (interpolation)

Drop:  c 55m (Trimble GeoXH 6000 summit and interpolated bwlch)

Dominance:  13.87% (Trimble GeoXH 6000 summit and interpolated bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

  

Mapping Mountains – Trimble Surveys – Mynydd Mallaen

 

04.09.21  Mynydd Mallaen (SN 722 455) 

Mynydd Mallaen (SN 722 455)

Many years ago when compiling the original Welsh P30s I remember looking at the two dimensional map profile of Mynydd Mallaen and being amazed at the vast bulk of the hill.  To its south other P30s connect to it and one or two rogue P20s make an appearance on its plateau, but in the main its land mass just comprises one significant hill. 

This hill is complex in nature with a southerly and south-easterly broad ridge descending from its highest point, which is marked by two substantial Bronze Age barrows and an Ordnance Survey triangulation pillar.  These two broad ridges have many undulations, with the Afon Gwenlais forming the central heartland comprising many streams forming its catchment area. 

The whole hill forms the southern extremity of what I know as the Elenydd.  To its north is extensive wilderness with many hills of similar height, broken by conifer plantations, bog and streams.  To its south the land gradually descends to friendlier climes. 

The hill is enclosed by steep sides with its highest point relatively close to its connecting bwlch; which is named Bwlch-y-rhiw.  It was from this bwlch that we headed for the summit. 

Prior to the ascent we had stopped at the bwlch on our way to Aber Bronddu farm and our visit to Banc y Graig (SN 699 452) and Cnepyn Cerrig (SN 706 460), and asked permission to park adjacent to farm buildings comprising large barns.  The permission was duly granted and a detailed route to the summit given us, this matched a route Aled had spotted from aerial maps. 

Leaving the car I followed Aled on a good green quad bike track aiming for a gate and its continuation beside a fence.  The afternoon heat was building but cloud cover gave a semblance of respite.  Across the valley the steep western side of Cnepyn Cerrig stared back at us, this is covered in oak and must be a beautiful sight on a sun drenched autumnal day with colour a plenty. 

As height was gained my energy levels began to plummet, which is starting to get a concern, but I generally know my body and how to pace a taxing walk, but still, this ascent was proving tiring. 

Approaching the plateau

Eventually we left the main quad bike track and veered leftward and continued up following another track on the moor, this crested the plateau near to a rock outcrop.  Here I lay on the ground and ate a banana, rested and tried to enjoy the fact of being on this marvellous hill. 

Approaching the small rock outcrop

Nearing the small rock outcrop

From here it was only a relatively short walk to the first of the two Bronze Age cairns.  This cairn is impressive and can be seen from many a mile away.  When originally built it was 25 metres in diameter and between 4 – 5m in height.  Nowadays it has been refashioned with a modern-day cairn built of its rock to signify its high point and a channel cut through on its western side which some report to be observational in nature toward the near triangulation pillar.  The size of the cairn is similar to its original construction. 

Approaching the summit of Mynydd Mallaen

When faced by such a construction it is always difficult to choose a point to survey as the natural summit could be under the cairn and ground on its periphery would then be lower than the hill’s natural height.  We decided upon two positions to survey, the first on the highest part of the ancient cairn that was solid and stable and had grass growing on it, the second at what was deemed to be the highest part of natural ground on the periphery of the cairn.  The latter was covered in grass and bilberry, but even this was seemingly atop part of the rock forming the lower part of the cairn. 

The first of two data sets gathered at the summit of Mynydd Mallaen

During data collection Aled headed off to investigate the other large cairn which has now been hollowed out to incorporate a wind shelter.  We stayed on top for about 20 minutes collecting the two data sets, and sitting at the base of the southerly cairn, resting, eating and talking.  By the time we set off back down the hill a cloud bank had pushed in from the south giving greying skies, although these broke again as we descended. 

The second of two data sets gathered at the summit of Mynydd Mallaen

On our descent we opted for a shortened route and cut across partly rough ground to connect back with the quad bike track.  This saved quite a distance and we then followed the track back to the awaiting car. 

All that remained was to survey the bwlch, this we judged to be positioned close to where the car was parked and was at or close to one of three gates leading from the narrow lane across the near fields and past a large barn. 

Gathering data at the bwlch of Mynydd Mallaen

I set the Trimble up to gather bwlch data and wandered back to the car to change and pack my gear away.  For me it had been a tiring day on the hill, but one that was extremely rewarding both in the hills visited and surveys conducted, but also in the meeting of Irwel and Eirwyn Jones at Aber Bronddu farm.  Just the drive home remained. 

 

Survey Result: 

 

Mynydd Mallaen (significant name change)

Summit Height:  460.9m (converted to OSGM15)

Summit Grid Reference:  SN 72217 45534

Bwlch Height:  259.2m (converted to OSGM15)

Bwlch Grid Reference:  SN 72372 46231

Drop:  201.7m

Dominance:  43.76%

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

 

 

 

 

Mapping Mountains – Trimble Surveys – Esgair Wen

04.09.21  Banc y Graig (SN 699 452) and Cnepyn Cerrig (SN 706 460) 

Cnepyn Cerrig (SN 706 460) 

When the initial compilation of the list that is now known as the Y Pedwarau – The 400m Hills of Wales was completed in November 2002 and sent to Rob Woodall who installed it on the RHB database, Cnepyn Cerrig (listed as Cefn Branddu, with the change favouring the local prioritised name) was included as a Pedwar based on the small uppermost 400m ring contour that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.  Subsequently, this hill remained listed as a Pedwar when the list was submitted for publication on Geoff Crowder’s v-g.me website in October 2004. 

This hill changed status from a Pedwar to a 390m Sub-Pedwar in May 2013 when the Y Pedwarau was published by Europeaklist.  This change was based on a 1,311ft (399.6m) Ordnance Survey height that appears at or near to the summit of this hill on the 1:10,560 map.  It has remained outside of the main Pedwar category ever since. 

Cnepyn Cerrig had been prioritised for an accurate survey since getting my Trimble GeoXH 6000, but as is the way of things, life and other stuff always seemed to get in the way.  However, the hill was finally visited today with six potential summit positions surveyed.  This will give a good spread for the height at its summit area and we’ll have to await post processing to find out if this hill breaks through the benchmark height of 400m. 

Prior to visiting I phoned Irwel Jones, the farmer from Aber Branddu to ask permission to park and use the track from his farm to visit these two hills.  The farm is positioned to the south of, and at the base of Cnepyn Cerrig.  He was a lovely person to speak with and during the conversation referred to the hill we had our main surveying aims concentrated on, as Cnepyn Cerrig.  He had no problem with this request and said he hoped to see us when we visited.  I was visiting these hills with Aled, and we hoped to meet Irwel when at the farm to make further place-name enquiries for the land he puts out sheep to graze, which includes Cnepyn Cerrig as well as Mynydd Mallaen. 

We were parked in the Aber Branddu farmyard at 9.40am, having met in Caersŵs at just before 8.00am.  It had been a good journey down with any lingering clag on the Mid Walian hills giving way to brightening conditions as I drove on the narrow minor lanes leading to Irwel’s farm. 

Before heading up the track we spoke with Irwel’s wife, who told us that he was working down valley, but would be back at lunchtime for the remainder of the day.  Thanking her, we then headed up the track. 

The track rises above Aber Branddu farm and heads for the bwlch between Cnepyn Cerrig and its higher and adjacent hill of Banc y Graig.  Conditions were warming up with broken cloud giving direct sunlight, which was pleasant but thankfully never overbearing.  The track headed on the eastern side of a steep stream laden cwm, on its western side red berried rowans stood out against the greened slopes of ferned bracken. 

The north-easterly slopes of Banc y Graig

We continued on a left hand branch of the track and crossed the steam, opting to visit the higher Banc y Graig first.  Beyond the stream the track soon petered out and continued as a vehicle track on rising ground.  This led to a fence, beyond which was the summit field. 

Arriving at the summit of Banc y Graig we both assessed the lay of land and judged ground away from another fence to be where the summit of the hill was positioned.  The Trimble was soon set up gathering data.  During data collection Aled walked down to admire the view back up valley and across to the imposing bulk of Mynydd Mallaen.  Whilst I walked a short distance to the north-west of the equipment and looked back to where it was set up, my initial intention was to gather a second data set beside the fence, however its position looked good and we judged a second data set was not necessary. 

Gathering data at the summit of Banc y Graig

Once the Trimble was closed down and packed away we headed down across fields to the connecting bwlch with Cnepyn Cerrig.  This was relatively easy to pinpoint and again, the Trimble was soon set up and quietly beeping away gathering individual datum points.  During data collection a Red Kite circled overhead, where once this would have been an extraordinary sight, nowadays it is common, and thankfully so.  These birds portray a grace of flight, seemingly effortless with their distinctive forked tails and streamlined bodies always a welcome sight. 

Gathering data at the bwlch of Cnepyn Cerrig

Leaving the bwlch we walked across the continuation of the closely cropped grazing field toward a gate giving access to the upper part of Cnepyn Cerrig, whose summit cairn now dominated the view ahead.  This cairn is relatively large for a hill of such height, with a number of rocks on and buried around its periphery. 

Banc y Graig (SN 699 452)

Aled nearing the summit cairn on Cnepyn Cerrig

When on the summit we set to work and debated how many surveys were required and importantly from what positions data should be gathered.  Ground to the north of the cairn looked as if it slightly rose from the base of the jumble of rock, whereas ground at the immediate south of the cairn was leading slightly downhill. 

Gathering one of the six data sets from the summit area of Cnepyn Cerrig

In all, six positions were surveyed, we could have taken more, but our aim was to determine whether this hill is over 400m in height and these data sets will give a good indication toward this. 

Gathering one of the six data sets from the summit area of Cnepyn Cerrig

Having spent an hour on the summit the Trimble was finally packed away and we descended toward the upper part of the track.  This gave good views over the steep sided river valley enclosing the Afon Cothi toward the bulk of Mynydd Mallaen, a hill we now wanted to visit. 

The track led back to Aber Bronddu farm where Irwel and his father; Eirwyn, joined us.  Aled unfolded the 1:25,000 map and the next 20 minutes was another one of those wonderful experiences where a farmer imparts the knowledge of their local land.  Much of this was done in Welsh; I understood some of the names given, but sadly not the detail of conversation.  This didn’t make it any less enjoyable as Welsh as a spoken language has a gentle feel to it and Irwel’s father was now pointing toward various streams, cymoedd and standing stones, giving many names that don’t appear on contemporary Ordnance Survey maps. 

Irwel and Eirwyn Jones of Aber Branddu farm

It was a delight to meet these two farmers; father and son and listen to them talk about the land they know well and work.  This also gave time to rest, as the early afternoon was now warming and we still had the ascent of Mynydd Mallaen ahead of us, so thanking Irwel and his father for their time I drove the short distance back up the narrowing valley to Bwlch-y-rhiw, where earlier in the morning we had asked permission to park.  Mynydd Mallaen looked daunting from this perspective, but a good green quad bike track led the majority of the way up it.  It still proved a slog to get to its high point though! 

 

Survey Result: 

 

Banc y Graig

Summit Height:  408.3m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 69992 45216 (Trimble GeoXH 6000)

Bwlch Height:  c 309m (interpolation)

Bwlch Grid Reference:  SN 69555 47145 (interpolation)

Drop:  c 99m (Trimble GeoXH 6000 summit and interpolated bwlch) (Hump reclassified to Subhump)

Dominance:  24.33% (Trimble GeoXH 6000 summit and interpolated bwlch)

 

 

 

Cnepyn Cerrig (significant name change)

Summit Height:  399.3m (converted to OSGM15)

Summit Grid Reference:  SN 70687 46081

Bwlch Height:  353.6m (converted to OSGM15)

Bwlch Grid Reference:  SN 70185 46118

Drop:  45.7m

Dominance:  11.45%

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

  

Mapping Mountains – Trimble Surveys – Beacon Hill

 

28.08.21  Stonewall Hill (SO 318 696) 

Stonewall Hill (SO 318 696)

Stonewall Hill had previously been surveyed on the 17^th July, just over five weeks later and Aled and I were again back on its summit.  We parked on the high narrow lane that skirts the border with England and headed back to its high point for more summit data.  The reason for doing so was that the higher of two previous summit surveys came to 399.97m, just 3cm below 400m. 

Stonewall Hill is one of two hills that are listed under the newly created status of National Top, each are now included in the Y Pedwarau – The 400m Hills of Wales list, the other being Hergest Ridge (SO 246 557).  The concept of National Tops is explained in a separate post and for the lists co-authored with Aled Williams, this status affects just these two hills. 

The summit of Stonewall Hill consists of a mound; its highest part has slight undulations but only comprises a small area.  We debated whether three or five further surveys were sufficient.  Four are documented and combined with the two previous surveys give six in all. 

Once on the summit Aled prodded around and we quickly decided the approximate position for each survey.  We then spent about 50 minutes hunkered below the survey equipment as it gathered one data set closely followed by another. 

Gathering data at the summit of Stonewall Hill

We debated whether this was the most unusual Trimble survey to have taken place, as the hill is now a National Top, which is a new concept, this was a re-survey, it is positioned within a couple of minutes’ walk from a road and the summit is on top of a mound of unknown origin. 

However, it is a good little top and has extensive views out toward the Clee Hills.  Once all data sets were gathered and stored we headed back to the car.  The processed result will tell us whether this hill makes it to the 400m height barrier! 

 

Survey Result: 

 

Stonewall Hill

Summit Height:  400.1m (converted to OSGM15) (400m Sub-Pedwar addition under National Top status) (significant height revision)

Summit Grid Reference:  SO 31823 69655  

Bwlch Height:  376.4m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Bwlch Grid Reference:  SO 31273 70279 (from previous Trimble GeoXH 6000 survey)

Drop:  23.8m

Dominance:  5.95%

 

 

For details on the 1^st summit survey of Stonewall Hill

 

For further details please consult the Trimble Survey Spreadsheet