Mapping Mountains – Significant Name Changes – 200m Twmpau

 

Cae Pen y Maen (SN 656 694) 

There has been a Significant Name Change to a hill that is listed in the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

LIDAR image of Cae Pen y Maen (SN 656 694)

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

200m Twmpau - Welsh hills at or above 200m and below 300m in height with 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 200m Twmpau by Myrddyn Phillips

The hill is adjoined to the Carn yr Hyrddod group of hills which are situated in the north-western part of the South Wales Region (Region B, Sub-Region B1), and it is positioned with the A485 road to its west, the B4575 road farther to its north, the B4340 road to its east and a minor road to its immediate north, and has the village of Lledrod towards the north-west. 

The hill appeared in the original Welsh 200m P30 list on Geoff Crowder’s v-g.me website under the transposed name of Comins Pen-y-banc, which is a prominent name positioned to the south-east of this hill’s summit on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps.  As this name implies this refers to named common land that is now indicated by its open access designation and which does not take in the summit of this hill.

Comins Pen-y-banc

297m

SN656694

135

199/213

Trig pillar at 295m to the North

 

During my early hill listing I paid little regard to name placement on the map, or the meaning of names and to what feature the name was appropriately applied to.  Therefore, I prioritised names for listing purposes that I now understand are either inappropriate or where another name is viewed as being more appropriate. 

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

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales. 

Extract from the Tithe map

The enclosed land where the summit of this hill is situated is given the number 143 on the Tithe map, this can be cross referenced against the apportionments; it is these apportionments that give the name of the owner or occupier of the land as well as the name of the land.  The land where the summit of this hill is situated is named as Cae Pen y Maen, with the details on the Tithe map appearing in the parish of Lledrod and in the county named as Cardigan. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the 200m Twmpau is Cae Pen y Maen and this was derived from the Tithe map. 

 

The full details for the hill are:

Group:  Carn yr Hyrddod

Name:  Cae Pen y Maen

Previously Listed Name:  Comins Pen-y-banc   

OS 1:50,000 map:  135

Summit Height:  296.6m (converted to OSGM15) 

Summit Grid Reference:  SN 65690 69496 

Bwlch Height:  268.8m (converted to OSGM15) 

Bwlch Grid Reference:  SN 66401 68910 

Drop:  27.9m 

 

Myrddyn Phillips (May 2021)

 

 

Mapping Mountains – Hill Reclassifications – 200m Twmpau

 

Cae Pen y Maen (SN 656 694) – 200m Twmpau reclassified to 200m Sub-Twmpau

There has been confirmation of a reclassification to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

LIDAR image of Cae Pen y Maen (SN 656 694)

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

200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 200m Twmpau by Myrddyn Phillips

The name the hill is listed by is Cae Pen y Maen and this was derived from the Tithe map, and it is adjoined to the Carn yr Hyrddod group of hills which are situated in the north-western part of the South Wales Region (Region B, Sub-Region B1), and it is positioned with the A485 road to its west, the B4575 road farther to its north, the B4340 road to its east and a minor road to its immediate north, and has the village of Lledrod towards the north-west. 

When the original 200m 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 summit height of 297m. 

When the accompanying sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 90m of drop, based on the 297m summit spot height and an estimated c 207m bwlch height, based on interpolation of 10m contouring between 200m – 210m that appear on the Ordnance Survey 1:25,000 Explorer map.  With an adjacent hill now listed as Banc y Maen Rochorlem (SN 675 691) given an estimated c 28m of drop, based on an estimated c 296m summit height and an estimated c 268m bwlch height, with both heights based on interpolation of 10m contouring that appear on the Ordnance Survey 1:25,000 Explorer map. 

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

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps and for Banc y Maen Rochorlem a 299m spot height was given on the area of its summit and as this is higher than the 297m spot height given Cae Pen y Maen the bylchau were swapped and each hill was reclassified. 

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. 

LIDAR analysis confirmed Banc y Maen Rochorlem as the higher summit and gives Cae Pen y Maen a summit height of 296.6m, and as the summit has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes. 

The Trimble GeoXH 6000 gathering data at the bwlch of Cae Pen y Maen

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

Prior to the Trimble GeoXH 6000 summit survey of this hill, the summit of Banc y Maen Rochorlem had also been surveyed and each result is given below: 

 

Banc y Maen Rochorlem:  299.3m at SN 67513 69184 

Cae Pen y Maen:  296.6m at SN 65690 69496 

 

Therefore, the confirmation of the reclassification of this hill to 200m Sub-Twmpau status is due to LIDAR analysis and a subsequent Trimble GeoXH 6000 survey, resulting in a 296.6m summit height and a 268.8m bwlch height, with these values giving this hill 27.9m of drop, which is insufficient for it to be classified as a 200m Twmpau. 

 

The full details for the hill are: 

Group:  Carn yr Hyrddod

Name:  Cae Pen y Maen 

OS 1:50,000 map:  135

Summit Height:  296.6m (converted to OSGM15) 

Summit Grid Reference:  SN 65690 69496 

Bwlch Height:  268.8m (converted to OSGM15) 

Bwlch Grid Reference:  SN 66401 68910 

Drop:  27.9m 

 

Myrddyn Phillips (May 2021)

 

 

 

Mapping Mountains – Trimble Surveys – Carn yr Hyrddod

15.10.20  Cae Pen y Maen (SN 656 694) 

LIDR image of Cae Pen y Maen (SN 656 694)

Cae Pen y Maen used to be listed as a 200m Twmpau and also a Subhump, with the latter list previously giving the hill 95m of drop, based on a 297m summit and 202m bwlch height.  Its P30 and Subhump status was subsequently relocated to its adjacent hill, which is listed as Banc y Maen Rochorlem (SN 675 691) in the 200m Twmpau list.  Its relocation was due to a 299m summit spot height that appeared on the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive coverage Map. 

Just over two weeks ago I’d visited the summit of Banc y Maen Rochorlem and surveyed it, and even though Cae Pen y Maen was relatively close the lack of time and daylight hours meant that I bi-passed it.  Today the opportunity to visit and survey this summit could not be missed and it had been pencilled in as one of nine hills to visit during the day with Charles Everett. 

By the time we parked just below the summit late afternoon light was casting long shadows on the narrow lane leading up toward the gate that gives access to the uppermost field of the hill.  This hill was the penultimate one of our mini-bagging bonanza and as with many others; it proved a delight to visit. 

Heading up the lane toward the gate to access the summit field

As Charles sat on the small plinth at the base of the trig pillar which is placed about 100 metres from the summit of the hill, I used the Trimble as a hand-held device to zero in on the ten figure grid reference that LIDAR analysis gives for the summit. 

The Trimble was soon set up gathering data, and I then stood back writing all necessary details in my note book.  During data collection a number of cows slowly crept toward the equipment, from the vantage point of the trig pillar Charles shouted over that they were still below it, therefore not interfering with satellite reception, which reassured me. 

The Trimble set-up position at the summit of Cae Pen y Maen

Once the allotted data were gathered and stored I closed the equipment down, packed it away and joined Charles by the trig.  A few minutes later we were back at the car, it had taken 25 minutes to visit and survey the hill; however I now wanted to get to grips with its connecting bwlch which looked as if it was positioned in a large bog. 

Even though I encouraged Charles to join me in the bwlch bog survey he politely and very wisely declined.  The bwlch of Cae Pen y Maen is positioned a short distance on the continuation of the narrow lane from where we had parked for the summit.  A few minutes later and I was parked beside the bwlch, it looked rather daunting and uninviting.  Thankfully I had brought my wellies. 

The bwlch of Cae Pen y Maen

Leaving Charles to relax in the car I headed off to its watery realm, firstly following a fence line adjacent to the bog which gave a semblance of dry ground and then I went for it.  The bog consisted of a multitude of tussocks and the further I ventured in to it, not surprisingly the more watery it became. 

I’d come with a ten figure grid reference for its interpolated position from the old 5m contouring on the OS Maps website.  It took me an inordinate amount of time to stumble through the tussocks zeroing in to this position, but eventually I arrived at it. 

Late afternoon light on an old ruined farm house

By the time I set the Trimble up to gather its allotted data the sun was low in the sky giving beautiful colour that illuminated the reed grass at the bwlch.  The wellies had proved a necessity and as the Trimble quietly beeped away I stood back and wondered how many people had ventured in to this place of bog and methane gas which rose as I stumbled my way through its tussocky depths. 

Gathering data at the bwlch of Cae Pen y Maen

Once I packed the Trimble away I had options to get out of the bog, I could retrace my inward route, or head over the bog to a gate and relatively safer ground on its other side, or head straight for the car, which looked back at me like a tempting beacon.  I chose the latter and proceeded to wade through all manner of unsavoury undergrowth. 

During data collection a large van pulled up beside my car and when I emerged out of the bog it proved to be the local farmer, who was wondering with an inquisitive smile on his face what on earth someone was doing immersed in his bog.  Charles had already explained that we were eccentrics and I added an in depth explanation of the Trimble and how critical a critical bwlch actually is, and a few moments later Charles and I were away heading for our last hill of the day. 

 

Survey Result: 

 

Cae Pen y Maen (significant name change)  

Summit Height:  296.6m (converted to OSGM15)

Summit Grid Reference:  SN 65690 69496 

Bwlch Height:  268.8m (converted to OSGM15)

Bwlch Grid Reference:  SN 66401 68910

Drop:  27.9m (200m Twmpau reclassified to 200m Sub-Twmpau)

Dominance:  9.40%

 

 

For further details please consult the Trimble Survey Spreadsheet