Mapping Mountains – Significant Height Revisions – Y Trichant – The 300m Hills of Wales

Cefn Isaf (SN 800 486) 

There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cefn Isaf (SN 800 486)

The criteria for the list that this height revision applies to are:

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Cefn Isaf, and it is adjoined to the Drygarn Fawr group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its south-east and the A483 road farther to its south-east, and has the town of Llanwrtyd (Llanwrtyd Wells) towards the east 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 summit height of 388m, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

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 summit image of Cefn Isaf (SN 800 486)

LIDAR analysis gives the summit height of this hill as 386.0m and this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated summit height and Ordnance Survey or Harvey map summit spot height, has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR.  Also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 386.0m and this was derived from LIDAR analysis, this is 2.0m lower than the previously listed summit height of 388m which appears as a spot height on the Ordnance Survey 1:25,000 Explorer map. 

 

The full details for the hill are: 

Group:  Drygarn Fawr 

Name:  Cefn Isaf 

OS 1:50,000 map:  147

Summit Height (New Height):  386.0m (LIDAR)                                                           

Summit Grid Reference:  SN 80031 48623 (LIDAR) 

Bwlch Height:  345.5m (LIDAR) 

Bwlch Grid Reference:  SN 80361 48591 (LIDAR) 

Drop:  40.5m (LIDAR) 

 

Myrddyn Phillips (February 2023)

 

 

 

 

  

Mapping Mountains – Hill Reclassifications – The Fours – The 400m Hills of England

Eastgate Quarry (NY 945 371) – 400m Sub-Four addition

There has been an addition to the listing of the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Eastgate Quarry (NY 945 371)

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

The Fours – The 400m Hills of England.  English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are three categories of sub hills, with this hill being included in the 400m Sub-Four category, the criteria for which are all English hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and the 2^nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24^th April 2018.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Eastgate Quarry and it is adjoined to the Burnhope Seat group of hills (Region 35, Section 35A: The Northern Pennines), and it is positioned with the A689 road to its north, and has the town of Stanhope towards the east north-east.

When the 2^nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, this hill was not included in the accompanying sub list, as it was considered not to meet the criteria used for this sub category, based on the hill being a part of a quarry and therefore contemporary Ordnance Survey maps do not show any meaningful contours. 

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

Since the original publication of this list there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current and digitally updated such as the interactive mapping on the WalkLakes and DataMapWales websites.

One of the mapping resources now available online is the WalkLakes website which hosts an interactive map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available maps and although no spot heights are given for this hill, its contours show the hill exists. 

Extract from the interactive mapping on the WalkLakes website

Another resource now available online is the interactive mapping hosted on the Welsh Government website and entitled the DataMapWales.  This mapping has 5m contours and its detail matches that produced from the OS Terrain 5 product, which compliments much of that produced from LIDAR.  It is this mapping that has a 408m summit height and col contouring between 385m – 390m. 

Extract from the interactive DataMapWales

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.

Therefore, the addition of this hill to 400m Sub-Four status is due to LIDAR analysis, resulting in a 407.5m summit height and a 384.9m col height, with these values giving this hill 22.6m of drop, which is sufficient for it to be classified as a 400m Sub-Four. 

 

The full details for the hill are:

Group:  Burnhope Seat

Name:  Eastgate Quarry

OS 1:50,000 map:  91, 92

Summit Height:  407.5m (LIDAR)

Summit Grid Reference:  NY 94599 37106 (LIDAR)

Col Height:  384.9m (LIDAR)

Col Grid Reference:  NY 94622 36938 (LIDAR)

Drop:  22.6m (LIDAR)

 

For the additions, deletions and reclassifications to The Fours – The 400m Hills of England reported on Mapping Mountains since the December 2013 publication of the 1^st edition of this list by Europeaklist please consult the following Change Registers:

 

The Fours

 

The Fours – 400m Sub-Four

 

The Fours – 390m Sub-Four

 

The Fours – 390m Double Sub-Four

 

Myrddyn Phillips and Aled Williams (February 2023) 

Mapping Mountains – Significant Name Changes – 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales

Ynys Aberteifi (SN 158 514) 

There has been a Significant Name Change to a hill that is listed in the 30-99m Twmpau and 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 conducted by Myrddyn Phillips. 

Ynys Aberteifi (SN 158 514)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m 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 30-99m Twmpau by Myrddyn Phillips

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 hill is adjoined to the Mynydd Bach group of hills, which are situated in the western part of South Wales (Region B, Sub-Region B1), and as its name implies; it is an island positioned off the west coast of Wales, and has town of Aerteifi (Cardigan) towards the south south-east.

Cardigan Island

52m

SN158515

145

35/198

The hill appeared in the original Welsh 30-99m P30 list on Geoff Crowder’s v-g.me website, under the transposed name of Cardigan Island, which is the name that appears for the island 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

The intricacies of language and prioritising one in favour of another for listing a hill is fraught with complication, with originating Cymraeg names being anglicised and also originating English names being cymricised, examples such as these are more common in border country and especially so for anglicised forms.  There is no steadfast rule that fits all, but as a standard a name that has its origins in the Welsh language and where this is substantiated by either historic documentation and/or contemporary usage should be prioritised in favour of a contemporary anglicised or English version of the name.  Likewise, if a name exists where an element of it is in English and if this name applies to a hill that is situated in a Welsh speaking part of Wales it is standard practice to use a full Welsh term for the name.  It is also standard practice to use a Welsh name for a hill if another name exists that has originated in a different language.

Therefore, the name this hill is now listed by in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales is Ynys Aberteifi, with the Welsh name for this hill prioritised over its English counterpart of Cardigan Island, which for listing purposes is standard practice.

 

The full details for the hill are:

Group:  Mynydd Bach

Name:  Ynys Aberteifi

Previously Listed Name:  Cardigan Island 

OS 1:50,000 map:  145

Summit Height:  52.5m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SN 15812 51487 (Trimble GeoXH 6000) 

Bwlch Height:  not applicable, sea level 

Bwlch Grid Reference:  not applicable, sea level 

Drop:  52.5m (Trimble GeoXH 6000)

Dominance:  100.00% (Trimble GeoXH 6000) 

 

Myrddyn Phillips (February 2023)

 

 

  

Mapping Mountains – Significant Name Changes – Y Trichant – The 300m Hills of Wales

Hen Gefn (SN 928 532) 

There has been a Significant Name Change to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Hen Gefn (SN 928 532)

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

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Drygarn Fawr group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its west and north-east, and the B4358 road to its south-east, and has the village of Beulah towards the south south-west.

The hill appeared in the original 300m height band of Welsh P30 hills published on Geoff Crowder’s v-g.me website, under the transposed name of Ysgubor y Cefn, which is a prominent name that appears to the west of this hill on the Ordnance Survey 1:25,000 Explorer map.

Ysgubor y Cefn

328m

SN929533

147

200

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 transpose the name of a building and presume it that 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 historic documents, through this form of research an appropriate name for the hill can usually be found.

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 81 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 Hen Gefn in the apportionments, with the details on the Tithe map appearing in the parish of Llanafan Fawr and in the county named as Brecon. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Hen Gefn and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Drygarn Fawr 

Name:  Hen Gefn 

Previously Listed Name:  Ysgubor y Cefn 

OS 1:50,000 map:  147

Summit Height:  327.3m (LIDAR)                                                           

Summit Grid Reference:  SN 92851 53245 (LIDAR) 

Bwlch Height:  271.8m (LIDAR) 

Bwlch Grid Reference:  SN 92229 53525 (LIDAR) 

Drop:  55.5m (LIDAR) 

 

Myrddyn Phillips (February 2023)

 

 

 

  

Mapping Mountains – Trimble Surveys – Moelwyn Mawr

21.01.23  Craig Stwlan (SH 667 446), Craig Ysgafn (SH 659 443) and Pt. 524.3m (SH 661 457) 

I drove up the narrow road to Tanygrisiau with trepidation, but thankfully the gritters had kept it in good condition.  In front of me were snow-covered peaks, cliffs and boulders; while behind me were the distant profiles of other snow-clad mountains commanded by the bulk of Arenig Fawr in full winter splendour.  Having parked the car, the rigid frames of winter boots were reluctantly fitted to cold feet, with crampons and a walking axe strapped to my bag in preparation for any icy ground. 

Arenig Fawr (Photo: Aled Williams)

The plan was to visit the series of rocky tops to the east of Llyn Stwlan, before contouring around the lake to Bwlch Stwlan, whereupon a traverse of Craig Ysgafn would take me to the summit of Moelwyn Mawr.  Three surveys were fitted into the walk and the absence of a companion indicated that I would have my hands full when conducting these. 

View ahead from Clogwyn yr Oen (Photo: Aled Williams)

Having scrambled up to the summit of Clogwyn yr Oen, the view ahead looked beautiful but daunting.  The powder snow was deep in places and made progress difficult as I broke trail towards Ceseiliau Moelwyn.  The Welsh Highlands Sub-Top of Clogwyn y Bustach was visited, but not surveyed given that its status within the list is secure.  Ahead stood Craig Stwlan, which I had noted as a marginal P20, as such, I knew Myrddyn Phillips would appreciate having the hill surveyed, given that it was a candidate for his 500m Sub-Twmpau list.

Clogwyn y Bustach (Photo: Aled Williams)

The summit of Craig Stwlan was first to be surveyed.  This went quickly and efficiently, no doubt benefitting from the experience of recent surveys.  The views were stunning and I could discern the path that I would take to reach Bwlch Stwlan.  The bwlch of Craig Stwlan took a bit longer to locate.  This is often dictated by the flat topography of low points, but the winter conditions doubled the challenge of the task.  Once data had been collected, I ploughed onwards through the snow, thankfully joining a set of tracks that greatly eased progress. 

Trimble atop Craig Stwlan (Photo: Aled Williams)

I then joined the path known locally as Llwybr Gaseg.  This was spectacular in the conditions, perched above the freezing waters of Llyn Stwlan and the snow plastered slopes and gullies of Moelwyn Mawr and Craig Ysgafn above.  Care was needed in places, but no ice was met.  Upon reaching Bwlch Stwlan, a splendid view of Traeth Mawr and Porthmadog opened out. 

Along Llwybr Gaseg (Photo: Aled Williams)

Bwlch Stwlan (Photo: Aled Williams)

Craig Ysgafn looked imposing from Bwlch Stwlan, but the scarcity of ice made it an easier endeavour.  The south top was visited, another Sub-Top in the Welsh Highlands list, followed by the highest summit of the ridge.  However, the focus was the northern top, which classified a marginal P10 stood a chance of being promoted to the sub-list of The Welsh Highlands list that I co-author with Myrddyn Phillips. 

Craig Ysgafn (Photo: Aled Williams)

Summit of Craig Ysgafn looking toward Moelwyn Mawr (Photo: Aled Williams)

The bwlch of the north top was found to be a snug notch in the ridge, with an airy view down a gully that led straight down to the depths of Llyn Stwlan.  The survey was completed quickly and a short climb led to the summit of the north top.  A number of rocky protuberances competed for the highest point and so the Abney level was used to identify the correct outcrop.  Three men bypassed the summit as data collected, looking a little perplexed at the beeping noises emanating from the Trimble! 

Bwlch of the north top of Craig Ysgafn (Photo: Aled Williams)

Surveying the bwlch of the north top of Craig Ysgafn (Photo: Aled Williams)

Having collected data I made my way to the base of the upper slope of Moelwyn Mawr.  A determined plod progressively took me up to the steep slope, where a surprising amount of deep snow had settled. 

Climbing Moelwyn Mawr (Photo: Aled Williams)

Summit ridge of Moelwyn Mawr (Photo: Aled Williams)

The summit ridge of Moelwyn Mawr looked airy and alpine-like, with Yr Wyddfa and its neighbouring Eryri peaks looking majestic to the north.  Below was Llyn Croesor and Bwlch Rhosydd, between which was a hillock that I had recently identified as a potential Sub-Top for the Welsh Highlands list and as such, was the third surveying objective of the day. 

Summit of Moelwyn Mawr (Photo: Aled Williams)

Yr Wyddfa (Photo: Aled Williams)

The steep descent from the summit of Moelwyn Mawr was undertaken slowly and carefully.  I had been warned from a Blaenau Ffestiniog local whom I had met on the way up Moelwyn Mawr that the snow above Rhosydd was deep.  This warning was confirmed by the appearance of a partially buried stile and fence!  However, I was yet again fortunate to follow in the footsteps of others and so quick progress was made to the shores of Llyn Croesor. 

Deep snow (Photo: Aled Williams)

The final surveying objective (Photo: Aled Williams)

On the other side of the lake stood the craggy hillock that was to be surveyed, a short but enjoyable climb led to the summit, whereupon the Trimble was placed on the highest point of outcropping rock.  The scenery was breath-taking and I felt fortunate to be out in such a wild place.  However, the serenity would soon be broken by hard surveying work! 

Surveying the summit (Photo: Aled Williams)

The bwlch of the hill was unexpectedly complex.  I quickly realised that the gap had been plugged by a dam that formerly held the north side of Llyn Croesor when operating at reservoir capacity.  Furthermore, an outflow leat consisting of earth and large slabs of rock had been built on the northern side of the dam. 

The bwlch (Photo: Aled Williams)

The dam wall (Photo: Aled Williams)

Ironically, the ice axe strapped to my bag was finally unclipped and brought into use, with the adze helping to displace snow so that a better assessment of the terraformed bwlch could be made.  Two sets of data were gathered with the Trimble; one at the bottom of the dam wall and one above the leat at the spot where remaining natural ground was identified.  However, post survey, further analysis work revealed that the natural bwlch may well be extant to the north of the wall within the leat. 

The leat (Photo: Aled Williams)

Looking back at the final hill (Photo: Aled Williams)

Once the surveying equipment was packed away, a set of snow tracks sing-posted the way to Bwlch Rhosydd and ultimately the way back to civilisation.  Before I set off, a quick glance behind my shoulder revealed beautiful cloud formations above Moelwyn Mawr, brought in from the east and heralding a change in the weather.  It had been a great day out and one no doubt to be remembered for years to come.

Clouds above Moelwyn Mawr (Photo: Aled Williams)

Walkers ascending Moelwyn Mawr (Photo: Aled Williams)

 

Moelwyn Mawr clouds (Photo: Aled Williams)

Aled Williams (January 2023)

 

Survey Result: 

 

Craig Stwlan

Summit Height:  568.4m (converted to OSGM15)

Summit Grid Reference:  SH 66736 44654

Bwlch Height:  548.3m (converted to OSGM15)

Bwlch Grid Reference:  SH 66693 44717

Drop:  20.1m (500m Sub-Twmpau addition)

Dominance:  3.53%

Craig Ysgafn

Summit Height:  688.3m (converted to OSGM15)

Summit Grid Reference:  SH 65973 44394

Bwlch Height:  678.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 65960 44382

Drop:  10.3m (Welsh Highland Sub addition)

Dominance:  1.49%

Pt. 524.3m

Summit Height:  524.3m (converted to OSGM15)

Summit Grid Reference:  SH 66117 45783

Bwlch Height:  513.5m (converted to OSGM15)

Bwlch Grid Reference:  SH 66131 45774

Drop:  10.7m (Welsh Highland Sub addition)

Dominance:  2.05%

 

For further details please consult the Trimble Survey Spreadsheet