Mapping Mountains – Hill Reclassifications – Y Pedwarau – The 400m Hills of Wales

 

Allt y Moch (SO 022 849) – 400m Sub-Pedwar reclassified to Pedwar

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams, which was prompted by detail produced by Joe Nuttall’s summit analysis programme and subsequent evaluation conducted by Ronnie Bowron. 

Allt y Moch (SO 022 849)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Allt y Moch and it is adjoined to the Pegwn Mawr group of hills which are situated in Mid and West Wales (Region B, Sub-Region B1), and it is positioned with a minor dead end road to its south and the A470 road to its north-west, and has the village of Llandinam towards the north. 

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website this hill was included in the accompanying Hills to be surveyed sub list as it had been surveyed using a basic levelling staff by Myrddyn Phillips on the 18^th August 2003 as having 96½ft / 29.4m of drop. 

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

The evaluation by Ronnie Bowron of the detail produced by Joe Nuttall’s summit analysis programme prompted this hill’s details to be re-assessed via the mapping on the OS Maps website.  This is the replacement for OS Get-a-map and had contours at 5m intervals which were 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.  The bwlch contours on this mapping were between 385m – 390m, therefore if the 421m summit spot height was accurate it meant this hill had at least 30m of drop and would qualify for Pedwar status.  Because of this it was prioritised for a Trimble GeoXH 6000 survey. 

Allt y Moch was surveyed over two days; 11^th July 2020 and 18^th October 2020, with seven data sets taken at the area of its bwlch and six data sets taken at the area of its summit, resulting in the hill now being listed with 30.1m of drop. 

The Trimble GeoXH 6000 gathering data at the bwlch of Allt y Moch

The Trimble GeoXH 6000 gathering data at the summit of Allt y Moch

Therefore, the reclassification of this hill from 400m Sub-Pedwar status is due to a Trimble GeoXH 6000 survey resulting in a 419.7m summit height and a 389.6m bwlch height, with these values giving this hill 30.1m of drop, which is sufficient for it to be classified as a Pedwar. 

 

The full details for the hill are:

Group:  Pegwn Mawr 

Name:  Allt y Moch 

OS 1:50,000 map:  136

Summit Height:  419.7m (converted to OSGM15) 

Summit Grid Reference:  SO 02202 84938 

Bwlch Height:  389.6m (converted to OSGM15) 

Bwlch Grid Reference:  SO 02366 84827 

Drop:  30.1m

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (October 2020)

  

Mapping Mountains – Summit Relocations – 500m Twmpau and The Welsh Highlands – Uchafion Cymru

Foel Fawr (SH 728 392)

There has been a Summit Relocation to a hill that is listed in the 500m Twmpau and The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams on the 19^th July 2020.

Foel Fawr (SH 728 392)

The criteria for the two listings that this summit relocation applies to are:

500m Twmpau – Welsh hills at or above 500m and below 600m in height that have 30m minimum drop, with an accompanying sub category entitled the 500m Sub-Twmpau consisting of all Welsh hills at or above 500m and below 600m in height that have 20m or more and below 30m of drop.  With the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.  The list is authored by Myrddyn Phillips and is published on Mapping Mountains in Google Doc format.

The 500m Twmpau by Myrddyn Phillips

The Welsh Highlands – Uchafion Cymru – This is the revised draft title for the Welsh 500m P15s list that takes in all hills in Wales at or above 500m in height with 15m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19th June 2019.

The Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Foel Fawr and it is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with the B4391 road to its north, the A470 road to its west and the A4212 road to its south, and has the village of Trawsfynydd towards the south-west.

When the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru was first compiled, this hill was listed with an estimated c 41m of drop based on the 528m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and which is positioned at SH 726 394, and an estimated c 487m bwlch height.

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

Since first compilation of the Welsh 500m P15 list there have been a number of Ordnance Survey 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 are current and digitally updated such as the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, and it was this map that showed a 528m map heighted twin summit positioned at SH 728 392.  The two 528m spot heights are also shown on the mapping hosted on the Magic Maps website.

Extract from the Magic Maps website

However, it was not until the survey with the Trimble GeoXH 6000 that the details for this hill could be accurately re-assessed.  The height and position for each summit is given below:

South-easterly summit:  528.611m at SH 72872 39284

North-westerly summit:  527.542m at SH 72621 39476

The above detail compared to the prioritised summit previously given comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the hill’s high point is found to be positioned; in a different field, to a different feature such as in a conifer plantation, placed within a different map contour, to a different point where a number of potential summit positions are within close proximity, or when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Gathering data at the higher of the Foel Fawr summits

Gathering data at the lower of the Foel Fawr summits

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 528.6m and this is positioned at SH 72872 39284, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, but is given a 528m spot height on the mapping hosted on the Magic Maps website, and is approximately 260 metres south-eastward from where the previously prioritised listed summit is positioned.

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Arenig

Name:  Foel Fawr

OS 1:50,000 map:  124

Summit Height:  528.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference (new position):  SH 72872 39284 (Trimble GeoXH 6000)

  

Bwlch Height:  485.5m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 73074 39525 (Trimble GeoXH 6000)

Drop:  43.1m (Trimble GeoXH 6000 summit and bwlch)

Myrddyn Phillips and Aled Williams (October 2020)

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

Coed y Fedw (SJ 201 613)

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 detail on contemporary maps produced from Ordnance Survey data.

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 Mountainson the 13th May 2017.

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

The hill is adjoined to the Moel y Gamelin group of hills, which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A494 road to its north-west and minor roads to its south and east, and has the village of Gwernymynydd towards the north-east.

When the original 300m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website this hill was not included in the Hills to be surveyed sub list that accompanied the main P30 list, as it was considered not to meet the criteria then used for this sub category. 

After the P30 lists were standardised, and interpolated heights and drop values also included, and the lists updated, this hill was listed with an estimated c 24m of drop based on an estimated c 317m summit height and an estimated c 293m bwlch height, and it was subsequently listed under the point (Pt. c 317m) notation.

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

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey 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 are current and digitally updated such as the mapping on the WalkLakes website, and it is this mapping that gives this hill a 318m summit spot height.

Extract from the WalkLakes website

The details for this hill were also re-assessed against the mapping on the OS Maps website.  This is the replacement for OS Get-a-map and until recent times had contours at 5m intervals which were proving consistently more accurate compared to the 5m contours that sometimes appear on the Ordnance Survey 1:25,000 Explorer map and used to appear on the online Vector Map Local.  This resulted in its bwlch height being listed as c 294m based on interpolation of 5m contouring between 290m – 295m.

These re-assessments resulted in the 318m spot height on the WalkLakes website taken as that for the summit, and as this mapping indicates this position to be in woodland adjoined to the larger Coed y Fedw it is appropriate to use this name for listing purposes.

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Coed y Fedw, and this was derived from the Ordnance Survey 1:25,000 Explorer map and the mapping on the WalkLakes website.

The full details for the hill are:

Group:  Moel y Gamelin

Name:  Coed y Fedw

Previously Listed Name:  Pt. c 317m

OS 1:50,000 map:  117

Summit Height:  318m (spot height)

                                                           

Summit Grid Reference:  SJ 20180 61372 (spot height)

Bwlch Height:  c 294m (interpolation)

Bwlch Grid Reference:  SJ 20367 61266 (interpolation)

Drop:  c 24m (spot height summit and interpolated bwlch)

Myrddyn Phillips (October 2020)

Mapping Mountains – Hill Reclassifications – Y Pedwarau – The 400m Hills of Wales

Bryn Catel (SN 697 506) – 400m Sub-Pedwar addition

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data.

Bryn Catel (SN 697 506)

This was initiated by Joe Nuttall who produced a summit analysis programme that used LIDAR with an alternative height map (DEM) allowing identification of summits and bylchau and thereby drops.  The resulting spreadsheet that Joe produced contains over 29,600 hills.

This spreadsheet is being evaluated by a number of people, including Ronnie Bowron, who passed the details of this hill to us.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Bryn Catel, and it is adjoined to the Esgair Wen group of hills, which are situated in the central part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with minor roads to its north, west and south and farther afield it has the B4343 road to its west, and the village of Llanddewibrefi towards the north-west.

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website this hill was not included in the main P30 list or in the Hills to be surveyed sub list that accompanied it, as it was considered not to meet the criteria then used for either category. 

After the P30 lists were standardised, and interpolated heights and drop values also included, the hill was still not included, and neither was it when the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013; it had been completely missed.

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

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey 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 are current and digitally updated such as the mapping on the WalkLakes website, and it is this mapping that gives this hill a 426m summit spot height.

Extract from the WalkLakes website

The details for this hill were also re-assessed against the mapping on the OS Maps website.  This is the replacement for OS Get-a-map and until recent times had contours at 5m intervals which were proving consistently more accurate compared to the 5m contours that sometimes appear on the Ordnance Survey 1:25,000 Explorer map and used to appear on the online Vector Map Local.  This resulted in its bwlch height being listed as an estimated c 402m based on interpolation of 5m contouring between 400m – 405m.

Extract from the OS Maps website

Therefore, the confirmation of the addition of this hill to 400m Sub-Pedwar status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 426m summit height and a c 402m bwlch height, with these values giving this hill c 24m of drop which is sufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Esgair Wen

 

Name:  Bryn Catel

OS 1:50,000 map:  146

Summit Height:  426m (spot height)

Summit Grid Reference:  SN 69703 50643 (spot height)

Bwlch Height:  c 402m (interpolation)

Bwlch Grid Reference:  SN 69786 50962 (interpolation)

Drop:  c 24m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (October 2020)

Mapping Mountains – Trimble Surveys – Arenig

19.07.20  Foel Fawr (SH 728 392), Foel Fawr (SH 726 394), Pt. 501.4m (SH 730 397) and Pt. 499.9m (SH 731 395)  

Foel Fawr (SH 728 392)

Between Llyn Trawsfynydd to the west and Llyn Conglog Mawr to the east lie a compact group of hills with Graig Wen (SH 739 394) the highest.  These hills are open with few fences and are bounded on the north by an invasive conifer plantation.  The summits overlook many small lakes and pools, each adding depth of variety and perspective to the landscape.  These hills seldom draw me back, but on the times I’ve visited they never disappoint.

Today I met Aled for our first walk together since earlier this year in January.  Covid-19 and its affects have altered many things and one was the travelling restriction which impacted greatly upon visiting the hills.  With this restriction now lifted it was good to be out again with a number of surveys planned.

We met close to Llyn Trawsfynydd and soon had our cars parked at the beginning of the track leading to Llyn yr Oerfel.  Behind the lake our first hill of the day; Foel Fawr, rose in a great bulk of steepening grass.  The continuation of the track led to the Braich-ddu Quarry with a vehicle track on the near moor leading us higher toward the southern ridge of Foel Fawr, and the first of its two 528m twin map heighted summits.

The two Foel Fawr summits with the old prioritised summit position on the left and the new higher summit on the right

This summit has a marvellous backdrop with the higher Eryli peaks lined one after another with the Moelwynion prominent and the distinctive profile of Moelwyn Mawr and Moelwyn Bach rising directly behind the large cairn atop the second and more northerly of the hill’s twin map heighted summits.  Once data were gathered and stored from the first summit and the connecting bwlch we were soon beside the cairn with the Trimble again gathering its allotted data.

The lower cairned summit of Foel Fawr with Moelwyn Bach and Moelwyn Mawr as backdrop

Gathering data from the summit of Foel Fawr

The main objective of the walk was to visit and hopefully survey a forested hill that is given a small 500m ring contour on the Ordnance Survey 1:25,000 Explorer map and a 504m spot height on Magic Maps and on the mapping on the WalkLakes website.  Its connecting bwlch is placed in a rather unsavoury and daunting looking bog.  We had come prepared with a series of ten figure grid references and hoped to take data from each point.

As the Trimble gathered data from the first position, which like all others was in a watery realm, Aled headed in to the conifers armed with an axe.  I then spent the next ten minutes listening to the quiet beep emanating from the survey equipment as each data point was collected and the ever distant crack of branches as Aled carved a way uphill toward the summit.  As he emerged back close to the bwlch he reported that the lower slopes were relatively easy but the higher slopes leading toward the summit were a mess, with numerous wind-blown trees now felled at all angles across the ground.

Gathering data at the first bog survey

Following Aled in to the confines we veered to the right and kept below the wind-blown trees which proved an easier route than the one Aled had investigated on his preliminary foray.  Just before the felled trees were encountered we came upon an unexpected crag, which is quite substantial and now left immersed in the confines of regimented conifers.

The crag leading toward the summit of the new forested Uchaf

The assault course now started, it was never too difficult and soon we had clambered our way over, under and through numerous trees and found the summit just beyond a small area that had direct sunlight breaking through the forest and a view of the sky which gave hope for data collection.  The high point consisted of a flat rock and we quickly devised a system to measure the offset between it and the Trimble placement with it sitting atop my rucksack which was on a conveniently felled tree giving it elevation above its surrounds.  Considering where we were it achieved its 0.1m accuracy level before data should be logged relatively quickly and we sat and chatted as it gathered its allotted data.  Reversing our inward route through the wind-blown felled trees we emerged in to the upright mature forest and contoured around the lower part of the plantation aiming for our next survey in the watery bog.  By keeping in the forest we avoided the impossibility of bog walking which may have proved hazardous!

Aled at the summit with the Trimble

Gathering data on the summit area of the new forested Uchaf

The ten figure grid reference Aled produced for the next survey which was listed as the connecting bwlch for the forested hill, was in the centre of a pool, which made me smile when I pinpointed it on the mapping on the OS Maps website.  As we emerged out of the conifer plantation we were back in the bog, thankfully a semblance of dryish ground led around its reed infested quagmire toward the pool.  I proceeded to set the Trimble up atop my rucksack on a large sponged grass tussock, measured the offset between its internal antenna and the ground at its base and as it beeped away collecting data, I lay across two tussocks close by, and considering the surrounding conditions I remained remarkably dry.

Gathering data beside the small pool

The next point to survey was a 499m map heighted top and Aled encouraged its bwlch to also be surveyed.  This proved to be beside a series of pools glinting blue in the late afternoon sunshine.  Once bwlch data were gathered and stored we headed for the last summit and sat in the warming conditions as another five minutes of data were gathered.

Beside the small lake heading toward the bwlch that connects with Pt. 499.9m

All that remained was another investigation of the bog to our immediate east which connects with Foel Fawr.  We’d already taken two data sets from its waters and with an elevated view we now decided to take two more, one from between the two main large pools which are connected via smaller channels and the last from the edge of the southerly pool.  Considering how horrendous this looked it proved relatively easy to accomplish.

The penultimate bog survey

The route back to the awaiting cars

All that remained was the walk out following a track-bed contouring around the southern ridge of Foel Fawr, which in time connected with our inward route and led back to the track leading to Llyn yr Oerfel.

Survey Result:

Foel Fawr

  

Summit Height:  528.6m (converted to OSGM15) (confirmed as higher than the top positioned at SH 72621 39476)

Summit Grid Reference:  SH 72872 39284 (summit relocation confirmed)

Bwlch Height:  485.5m (converted to OSGM15)

Bwlch Grid Reference:  SH 73074 39525

Drop:  43.1m

Dominance:  8.15%

Foel Fawr 

 

Summit Height:  527.5m (converted to OSGM15) (confirmed as lower than the top positioned at SH 72872 39284)

Summit Grid Reference:  SH 72621 39476

Bwlch Height:  515.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 72815 39394

Drop:  12.6m

Dominance:  2.38% 

Pt. 501.4m 

 

Summit Height:  501.4m (converted to OSGM15)

Summit Grid Reference:  SH 73011 39784

Bwlch Height:  485.5m (Trimble GeoXH 6000 data set spread)

Bwlch Grid Reference:  SH 73105 39632 (from aerial map comparisons)

Drop:  15.9m (Uchaf addition confirmed)

Dominance:  3.17%

Pt. 499.9m 

 

Summit Height:  499.9m (converted to OSGM15)

Summit Grid Reference:  SH 73187 39525

Bwlch Height:  489.6m (converted to OSGM15)

Bwlch Grid Reference:  SH 73419 39616

Drop:  10.3m

Dominance:  2.07%

For further details please consult the Trimble Survey Spreadsheet