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 – Hill Reclassifications – Humps

Banc y Graig (SN 699 452) – Hump reclassified to Subhump

This is the thirty sixth in a series of Hill Reclassification posts that detail hills whose status has either been altered in the listing of the Humps (HUndred Metre Prominences) through map study and / or surveys that I have instigated, or it is the recommendation that their status is altered.

Banc y Graig (SN 699 452)

Many preceding posts detailing these hill reclassifications are retrospective as they were initiated from studying the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map, or from surveying with the Trimble GeoXH 6000, or from LIDAR analysis, and for this reclassification that affected the Humps the email I posted on the RHB Yahoo Group forum in relation to this hill was dated 09.09.19.

The listing of Humps was published in book format by Lulu in 2009 and entitled More Relative Hills of Britain, its author; Mark Jackson gives credit to a number of people who contributed toward the formation of this list, these include; Eric Yeaman, Alan Dawson, Clem Clements, Rob Woodall, Bernie Hughes, Pete Ridges and others.  When the list was published in book format there were 2987 Humps listed with their criteria being any British hill that has 100m or more of drop, irrespective of their height.  Accompanying the main list is a sub category entitled Subhumps, with the criteria being any British hill that has 90m or more and below 100m of drop.

More Relative Hills of Britain by Mark Jackson

The details for the reclassification appear below:

There has been a reclassification to the listing of the Humps (HUndred Metre Prominences) instigated by study of contemporary Ordnance Survey maps conducted by Myrddyn Phillips.

The name the hill is listed by is Banc y Graig and it is adjoined to the Elenydd group of hills, and it is positioned with the A482 road to its south-west and the A483 road to its south-east, and has the town of Llanbedr Pont Steffan (Lampeter) towards the west north-west and the town of Llanymddyfri (Llandovery) towards the south-east.

Prior to this reclassification this hill was listed as a Hump with 101m of drop based on the 408m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and a bwlch height of 307m based on the spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.  This spot height is also shown on Ordnance Survey data that appears on the Magic Maps website.

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

Extract from the Magic Maps website

The details for this hill were re-assessed using a combination of various scaled Ordnance Survey maps, including the mapping on the OS Maps website.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.

Extract from the OS Maps website

Importantly the 307m spot height that appeared on the Vector Map Local and is still shown on the Magic Maps website is positioned at SN 69521 47114.  This position is not where the 5m contours on the OS Maps website indicate the critical bwlch to be positioned and a better representation of this bwlch height and position is c 309m at SN 69555 47145, and when coupled with the 408m summit height gives this hill an estimated c 99m of drop, which is insufficient for it to be reclassified as a Hump, with the summit of this hill subsequently surveyed with the Trimble GeoXH 6000.

The reclassification of this hill from Hump to SubHump status was accepted and its new classification augmented in to the listing of the Humps on the 14.09.19.

The full details for the hill are:

Name:  Banc y Graig

OS 1:50,000 map:  146

OS 1:25,000 map:  187, 199

Summit Height:  408m (spot height as listed in the Humps, with the Trimble GeoXH 6000 survey giving 408.3m)

Summit Grid Reference:  SN 69981 45212 (hand-held GPS via DoBIH as listed in the Humps, with the Trimble GeoXH 6000 survey giving SN 69992 45216)

Bwlch Height:  c 309m (interpolation)

Bwlch Grid Reference:  SN 69555 47145 (interpolation)

Drop:  c 99m (spot height summit and interpolated bwlch)

Myrddyn Phillips (February 2020)