Mapping Mountains – Summit Relocations – Y Trichant – The 300m Hills of Wales

Cwm Fron (SN 966 808) 

There has been a Summit Relocation 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 Cwm Fron (SN 966 808)

The criteria for the list that this summit relocation applies to:

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 Cwm Fron, and it is adjoined to the Hirddywel group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B2), and it is positioned with the A470 road to its north-west, a minor road to its south-west and the B4518 road to its east, and has the town of Llanidloes towards the north.

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 379m summit height, based on the spot height positioned at SN 96621 81382 that appears on the Ordnance Survey 1:25,000 Exlorer map.  With the contemporary Ordnance Survey 1:50,000 Landranger map giving a 378m spot height positioned at SN 96642 80819. 

Extract from the Ordnance Survey 1:50,000 Landranger 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 this hill it had a 379m summit spot height positioned at SN 96629 80855, this position is close to where the 379m spot height appears on the Ordnance Survey 1:50,000 Landranger map.  This resulted in the hill being listed with twin 379m summits. 

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 Cwm Fron (SN 966 808)

LIDAR analysis gives the highest ground on this hill as 377.7m positioned at SN 96629 80855, with LIDAR giving the northerly position as 377.5m positioned at SN 96704 81464, and this in relation to the originally listed summit position comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, to a different point where a number of potential summit positions are within close proximity, 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 or covered reservoir that is considered 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.

Therefore, the summit height produced by LIDAR analysis is 377.7m and this is positioned at SN 96629 80855, this position is not given a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map, and is approximately 610 metres southward from where the originally listed summit is positioned. 

 

The full details for the hill are:

Group:  Hirddywel 

Name:  Cwm Fron 

OS 1:50,000 map:  136

Summit Height:  377.7m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 96629 80855 (LIDAR) 

Bwlch Height:  318.2m (LIDAR) 

Bwlch Grid Reference:  SN 97301 81730 (LIDAR) 

Drop:  59.5m (LIDAR) 

 

Myrddyn Phillips (January 2025) 

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

Jopplety How (NY 265 163) – 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 Jopplety How (NY 265 163)

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 is a sub list entitled the Sub-Fours, the criteria for which are all English hills at or above 400m and below 500m in height that have 15m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available to download in Google Doc format from the Mapping Mountains site.

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

The name the hill is listed by is Jopplety How, and it is adjoined to the High Raise group of hills, which are situated in the English Lake District, and it is positioned with the B5289 road to its west and a minor road to its east, and has the small community of Rosthwaite towards the south south-west.

When the Introduction to the first group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published by Mapping Mountains on the 10^th September 2022, it was announced that the accompanying sub lists were being revised with the two 390m categories dispensed with and the criteria and name of the 400m Sub-Fours revised.  The one accompanying sub list is now named the Sub-Fours with its criteria being all English hills 400m and above and below 500m in height that have 15m and more and below 30m of drop.

Prior to this revision this hill was not listed, with subsequent interpolation giving it an estimated c 9m of drop, based on an estimated c 403m summit height and an estimated c 394m col height, with both heights based on interpolation of 10m contouring 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.

Therefore, the addition of this hill to Sub-Four status is due to LIDAR analysis, resulting in a 409.1m summit height and a 391.8m col height, with these values giving this hill 17.25m of drop, which is sufficient for it to be classified as a Sub-Four.

 

The full details for the hill are:

Group:  High Raise

Name:  Jopplety How

OS 1:50,000 map:  89, 90

Summit Height:  409.1m (LIDAR)

Summit Grid Reference:  NY 26554 16377 (LIDAR)

Col Height:  391.8m (LIDAR)

Col Grid Reference:  NY 26570 16431 (LIDAR)

Drop:  17.25m (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

 

Sub-Fours

 

Myrddyn Phillips and Aled Williams (January 2025)

  

Mapping Mountains – Summit Relocations – 200m Twmpau

 

Pen y Ffridd (SJ 114 112) 

There has been a Summit Relocation 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 conducted by Myrddyn Phillips. 

LIDAR image of Pen y Ffridd (SJ 114 112)

The criteria for the list that this summit relocation 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.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The name the hill is listed by is Pen y Ffridd, and it is adjoined to the Esgeiriau Gwynion group of hills, which are situated in the southern part of North Wales (Region A, Sub-Region A3), and it is positioned with minor roads to its north-east and west, and the A495 road to its south-east, and has the village of Meifod towards the north-east.

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 218m summit height, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map.

After the accompanying sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 41m of drop, based on the 218m summit spot height positioned at SJ 11499 11222 and an estimated c 177m bwlch height, based on interpolation of 10m contouring between 170m - 180m. 

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 analysis gives the highest ground on this hill as 219.8m positioned at SJ 11495 11219 and SJ 11488 11217.  However, this is a part of a raised field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Pen y Ffridd (SJ 114 112)

The height produced by LIDAR analysis to the highest remaining natural ground on this hill is 219.6m and this is positioned at SJ 11492 11221, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, to a different point where a number of potential summit positions are within close proximity, 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 or covered reservoir that is considered 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.

Therefore, the summit height produced by LIDAR analysis is 219.6m and this is positioned at SJ 11492 11221, this position is relatively close to where the spot height appears on the Ordnance Survey 1:25,000 Explorer map, and is approximately 3 metres north-westward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Esgeiriau Gwynion 

Name:  Pen y Ffridd 

OS 1:50,000 map:  125

Summit Height:  219.6m (LIDAR) 

Summit Grid Reference (New Position):  SJ 11492 11221 (LIDAR) 

Bwlch Height:  173.0m (LIDAR) 

Bwlch Grid Reference:  SJ 10462 11208 (LIDAR) 

Drop:  46.65m (LIDAR) 

 

Myrddyn Phillips (January 2025)

 

 

Mapping Mountains – 2024 Retrospective

 

Many years ago a good hill walking friend advised me that once the lists I had originated were put in spreadsheet form they would never be complete, as there would always be things that required updating.  This same philosophy is applicable to the Mapping Mountains site; however that doesn’t stop me from tinkering in the background and through updates making the various headings more accessible.  Therefore, the last year has been one of consolidation with a variety of headings either being updated or fully revamped, so let us now look at 2024 and the Mapping Mountains year in review:

 

January:

On the 10^th January the latest group of hills for The Fours – The 400m Hills of England was published.  This list now includes P15 subs and started publication on the 10^th September 2022, with the last group of hills scheduled for publication on the 10^th July 2024.

 

 

January: 

On the 27^th January the last post instigated by Aled Williams’ LIDAR analysis of all Welsh hills at and above 500m was published on Mapping Mountains.  These hills comprise the listing of The Welsh Highlands – Uchafion Cymru and the LIDAR analysis took Aled many months to complete and entailed hundreds of hills, with the last post detailing a hill reclassification for Clipiau Duon. 

 

 

March:

I wanted to revamp the listing of Y Trechol – The Dominant Hills of Wales for a long time.  This list originated in 2009 and its publication on Mapping Mountains started in December 2015.  The list is available in its entirety in Google Doc format and a part of its revamp has been to alter the columns within the list with the Regions and Sub-Regions now dispensed with and the remaining columns amended to match those used in the latest version of The Fours – The 400m Hills of England list.  This revamp started in earnest during March and is ongoing.  The list will take a long time to fully update, however one thing that is complete is that all interpolated summit heights have now been LIDAR’ed.

 

 

April:

During the month of April the last post generated by the update of The Fours – The 400m Hills of England list was published on Mapping Mountains.  The updated version of this list started publication in group format in September 2022, with the last group and therefore the fully updated list published later in the year in July.  These posts detail all major alterations to the list, including status, height revision, summit relocation and name change. 

 

 

April:

The extended LIDAR coverage for Wales has enabled a multitude of hills to be accurately reassessed.  It has also enabled a number of headings on the Mapping Mountains site to be updated with more accurate numerical data.  During April this process was extended to the Change Register for the Welsh Marilyns.  This was originally published in March 2020 and all relevant detail has now been updated with the latest available LIDAR. 

 

 

May:

Another addition to the posts on Mapping Mountains has been the Monthly Synopsis.  These detail all major changes, both new, confirmation and retrospective that have appeared on Mapping Mountains during the preceding calendar month, with the first of these published on the 31st May 2024. 

 

 

July:

On the 10^th July the final group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published on Mapping Mountains.  It had taken 23 months to complete the revised list since the first group of hills were published on the 10^th September 2022.  The Mapping Mountains publication was soon followed by the updated and revised listing appearing on the Haroldstreet website and an article being published on the UKHillwalking website. 

 

 

August                 

Photo: Aled Williams

Two surveys of note were conducted with the Trimble GeoXH 6000 during the year; both of which by Aled Williams.  The first of these was in August with the heighting of Craig Cwrwgl (SH 615 615).  This is an upthrust of rock adjoining the north-easterly face of Elidir Fawr in the Glyderau.  To attain the summit requires a rock climb.  Aled surveyed both the summit and connecting bwlch for Welsh Highland P15 status.  The pillar eventually topped out with 14.5m of drop, so although it is not a P15, it is confirmed in the ranks of our Welsh Highland Subs. 

 

 

September:         

Part of the joy of having the Mapping Mountains site is that it can be used to either make statements or to delve in to the intricacies of terms associated with hill lists.  During September an article was published with the snappy little title of Terms applied to Hill Status alteration.  Where four main terms previously existed; addition, reclassification, deletion and reinstatement, there is now a fifth and even a sixth; Exclusion and Rejection.  Is this the proverbial eureka moment or a sign of a misplaced adulthood! 

 

 

October:              

Photo: Aled Williams

The second survey of note was Crib Goch (SH 624 551).  This hill was long sought after to be Trimbled and it was done so by Aled Williams.  This survey now completes the surveying via GNSS receiver of the 3,000ft’ers adjoined to the Yr Wyddfa group of hills.  All that now remains in Wales are a batch of hills in the Carneddau and one in the Glyderau.  Once these are complete we will have accurate heights for all the Welsh 3,000ft’ers. 

 

 

November:          

At the beginning of November I added another column to the Trimble Survey Spreadsheet.  This document catalogues all necessary detail relating to surveying with the Trimble GeoXH 6000.  The new column details the raw unprocessed height data documented by the Trimble.  Some of these heights are relatively close to the processed data result; others are not, with a multitude of heights between.  Not surprisingly the conclusion in comparison between unprocessed and processed data is that the former should never be used to quote any accurate height. 

 

 

November:       

Late on the 19^th November I had a phone call telling me I had just been mentioned on QI on BBC2.  It was towards the end of the programme and involved things that have changed size; London buses were mentioned as indeed was an Olympic swimming pool, this led on to the Wales/England border and how a mountain surveyor from Mapping Mountains named……. (yes they mentioned me by name with good pronunciation by Sandi Toksvig) had found that the border between these two countries was incorrectly placed resulting in Wales being too big.  It was all rather surreal.

 

December:        

On the evening of 24^th December I had an early Christmas present as the site views for Mapping Mountains exceeded 1,000,000.  This proved an excellent way to end the 2024 retrospective.

 

Year’s End: 

During 2024 another grand sweep for the year was achieved, as a separate post has been uploaded to Mapping Mountains on each and every day of the year. 

 

 

The Year Ahead: 

And what is in store for Mapping Mountains during 2025; the simple answer is, I don’t know.  Nothing major is planned.  However, I’m sure that the year ahead will bring one or two surprises with more hills surveyed and LIDAR’ed, and more tinkering and updating with the Mapping Mountains site. 

Lastly, I would like to thank all those who visit Mapping Mountains for their continued support and I hope the year ahead brings lots of happiness and fun-filled days on the hill. 

 

Myrddyn Phillips (1^st January 2025)