Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

Trawsallt (SN 782 701) – Welsh Highland Sub addition 

There has been an addition to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Trawsallt (SN 782 701)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Trawsallt and it is adjoined to the Carn yr Hyrddod 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 and the B4574 road to its north, the B4343 road to its west and a minor road to its south, and has the village of Pont-rhyd-y-groes towards the north-west.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 7m of drop, based on the 564m summit spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and an estimated c 557m bwlch height, based on interpolation of 5m contouring that appeared on online mapping. 

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 Welsh Highland Sub status is due to LIDAR analysis, resulting in a 564.5m summit height and a 552.8m bwlch height, with these values giving this hill 11.7m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Carn yr Hyrddod

Name:  Trawsallt

OS 1:50,000 map:  135, 147

Summit Height:  564.5m (LIDAR)

Summit Grid Reference:  SN 78298 70193 (LIDAR)

Bwlch Height:  552.8m (LIDAR)

Bwlch Grid Reference:  SN 78147 70153 (LIDAR)   

Drop:  11.7m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (December 2023)

  

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

 

Rhos Ymryson (SN 460 499) 

There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales and Y Trechol – The Dominant 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 Rhos Ymryson (SN 460 499)

The criteria for the two listings 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

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 name the hill is listed by is Rhos Ymryson, and it 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 it is positioned with the B4338 road to its north-east, a minor road to its north-west and the A475 road to its south, and has the village of Llanwenog towards the south-east. 

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

Extract from the Ordnance Survey 1:50,000 Landranger map

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 327m summit height, based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and which is positioned at SN 459 500.  However, this height is given to the top of a covered reservoir, whilst the contemporary Ordnance Survey 1:50,000 Landranger map gives a 324m summit spot height, which conforms with the rounded up 1062ft (323.7m) height shown on the Ordnance Surveys series of Six-Inch maps. 

Extract from the Ordnance Survey series of Six-Inch maps

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 Rhos Ymryson (SN 460 499)

The summit height produced by LIDAR analysis to the highest remaining natural ground on this hill is 323.3m and is positioned at SN 46032 49996, 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 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 323.3m and this was derived from LIDAR analysis, this is 3.7m lower than the originally listed summit height of 327m, which was based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

 

The full details for the hill are: 

Group:  Mynydd Bach 

Name:  Rhos Ymryson 

OS 1:50,000 map:  146

Summit Height (New Height):  323.3m (LIDAR)                                                           

Summit Grid Reference:  SN 46032 49996 (LIDAR) 

Bwlch Height:  162.6m (LIDAR) 

Bwlch Grid Reference:  SN 61745 57992 (LIDAR) 

Drop:  160.8m (LIDAR) 

Dominance:  49.72% (LIDAR) 

 

Myrddyn Phillips (December 2023)

  

Mapping Mountains – Significant Name Changes – 200m Twmpau

Cae Cefn (SN 547 121) 

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 detail produced by Joe Nuttall in his surface analysis programme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Myrddyn Phillips. 

LIDAR image of Cae Cefn (SN 547 121)

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 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 hill is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with a minor road to its north and east, the B4310 road to its south-west and the A476 road to its south-east, and has the village of Cross Hands towards the east north-east.

The hill appeared in the original Welsh 200m P30 list on Geoff Crowder’s v-g.me website listed as a twin top, with this hill appearing under the transposed and invented name of Tumble Hill, with an accompanying note for this top stating; Name from town to the South-West.

Tumble Hill

220c

SN547121

159

178

Name from town to the South-West

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 near town and add the word Hill to it.  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 2628 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 Cefn in the apportionments, with the details on the Tithe map appearing in the parish of Llanon and in the county named as Carmarthenshire. 

Extract from the apportionments

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

 

The full details for the hill are:

Group:  Mynydd Sylen

Name:  Cae Cefn

Previously Listed Name:  Tumble Hill   

OS 1:50,000 map:  159

Summit Height:  226.5m (LIDAR) 

Summit Grid Reference:  SN 54711 12139 (LIDAR) 

Bwlch Height:  196.8m (LIDAR) 

Bwlch Grid Reference:  SN 54478 11503 (LIDAR) 

Drop:  29.7m (LIDAR) 

 

Myrddyn Phillips (December 2023)

 

 

 

 

 

Mapping Mountains – Significant Height Revisions – The Fours – The 400m Hills of England

Grindle (SO 430 926) 

There has been a Significant Height Revision to a hill that is listed in 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 initially conducted by Aled Williams and subsequently by Myrddyn Phillips.                                                                                                             

LIDAR image of Grindle (SO 430 926)

The criteria for the list this height revision affects 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, the 400m Sub-Four category, the 390m Sub-Four category and the 390m Double Sub-Four category.  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 Grindle, and it is adjoined to the Stiperstones group of hills, which are situated in the county of Shropshire close to the Welsh border, and it is positioned with minor roads to its north and west, and the B4577 and A49 roads to its east, and has the town of Church Stretton towards the east north-east.

When the 1^st edition of the The Fours was published by Europeaklist in December 2013, this hill was listed with an estimated c 53m of drop, with a 459m summit height positioned at SO 430 926 based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and an estimated c 406m col height, based on interpolation of 5m contouring between 405m – 410m. 

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

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 listed with a 460.2m summit height, based on a Trimble GeoXH 6000 survey.

However, it was not until LIDAR became available that the details produced by the Trimble GeoXH 6000 survey 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 Grindle (SO 430 926)

LIDAR analysis gives the highest ground on this hill as 460.5m positioned at SO 43009 92663, and this is being prioritised over the result produced by the Trimble GeoXH 6000, 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 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 460.5m and this was derived from LIDAR analysis, this position is adjacent to where the 459m spot height appears on the Ordnance Survey 1:25,000 Explorer map and is 1.5m higher than it and importantly signifies contemporary Ordnance Surveys maps are missing an uppermost 460m ring contour. 

 

The full details for the hill are:

Group:  Stiperstones

Name:  Grindle

OS 1:50,000 map:  137

Summit Height (New Height):  460.5m (LIDAR)

Summit Grid Reference:  SO 43009 92663 (LIDAR)

Col Height:  406.6m (LIDAR)

Col Grid Reference:  SO 42581 92764 (LIDAR)

Drop:  53.9m (LIDAR)

 

Myrddyn Phillips and Aled Williams (December 2023)

 

 

  

Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

Pen y Bwlch (SN 929 669) – Welsh Highland Sub deletion 

There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pen y Bwlch (SN 929 669)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Pen y Bwlch it is adjoined to the Y Garn 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 north-east and west, and the B4518 road to its south-east, and has the town of Rhaeadr Gwy towards the east north-east.

This hill was originally listed as a sub due to a basic levelling survey conducted by Myrddyn Phillips on the 17.08.05 resulting in a 47ft (14.3m) drop value, with the summit height listed as an estimated c 500m, based on interpolation of the small uppermost 500m ring contour that appears on the contemporary Ordnance Survey 1:25,000 Explorer map. 

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

When the initial P10 sub list was completed in June 2020 this hill was included as a sub with an accompanying note stating:

LIDAR 2m DSM bwlch by AW. BLS by MP on 17/08/2005 giving 47ft (14.3m). Adding the BLS drop result to the bwlch height determined via LIDAR analysis gives a summit height of 500.1m. Summit height is inconsistent on OS maps, giving a range of 499m to 500m. Partial coverage LIDAR 2m DSM by AW gives 498.1m summit-area high point at SN 92831 66910. The OS 6" Map (1888) gives a 1633ft (497.7m) summit-area high point at SN 93067 66918.

However, it was not until full LIDAR coverage 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 deletion of this hill from Welsh Highland Sub status is due to LIDAR analysis, resulting in a 499.6m summit height and a 485.6m bwlch height, with these values giving this hill 14.05m of drop, with its height being insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Y Garn

Name:  Pen y Bwlch

OS 1:50,000 map:  136, 147

Summit Height:  499.6m (LIDAR)

Summit Grid Reference:  SN 92901 66972 (LIDAR)

Bwlch Height:  485.6m (LIDAR)

Bwlch Grid Reference:  SN 92677 66989 (LIDAR)   

Drop:  14.05m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (December 2023)