Mapping Mountains – Hill Reclassifications – 30-99m Twmpau

Pen Brwsh (SM 880 396) – 30-99m Twmpau addition 

There has been confirmation of an addition to the list of 30-99m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived by LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pen Brwsh (SM 880 396)

The criteria for the list that this addition 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

The name the hill is listed by is Pen Brwsh, and it is adjoined to the Garn Fawr group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1).  As this is a tidal island it is surrounded by sea at high tide, and it is positioned with a minor road to its east and the A487 road farther to its south-east, and has the town of Abergwaun (Fishguard) towards the east south-east.

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

After the 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 42m of drop, based on an estimated c 42m summit height based on interpolation of its uppermost 40m ring contour 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 confirmation of the addition of this hill to 30-99m Twmpau status is due to LIDAR analysis, resulting in a 41.8m summit height and a 0.2m bwlch height, with these values giving this hill 41.6m of drop, which is sufficient for it to be classified as a 30-99m Twmpau. 

 

The full details for the hill are: 

Group:  Garn Fawr 

Name:  Pen Brwsh 

OS 1:50,000 map:  157

Summit Height:  41.8m (LIDAR) 

Summit Grid Reference:  SM 88067 39675 (LIDAR)               

Bwlch Height:  0.2m (LIDAR) 

Bwlch Grid Reference:  SM 88117 39673 (LIDAR) 

Drop:  41.6m (LIDAR) 

 

Myrddyn Phillips (June 2023)

 

 

 

  

Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales

 

Pigyn Shôn Nicolas (SN 667 354) – Sub-Trichant addition

There has been an addition to the list of 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 addition 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 Pigyn Shôn Nicolas, and it is adjoined to the Mynydd Mallaen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north, west and south-east, and the B4302 road to its north-west, and has the town of Llanymddyfri (Llandovery) towards the east.

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

After the 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 19m of drop, based on the 322m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map at SN 66753 35404 and SN 66689 34767 and an estimated c 303m bwlch height, based on interpolation of 10m contouring between 300m – 310m. 

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

One of the resources recently available online is 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.  Although the mapping on the OS Maps website no longer has contours at 5m intervals, such contours are represented on other mapping available online and for this hill this mapping has bwlch contouring between 300m – 305m, with interpolation placing the height of the bwlch as an estimated c 301m. 

Interactive map with 5m contouring available online

Therefore, the addition of this hill to Sub-Trichant status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 322m summit height and an estimated c 301m bwlch height, with these values giving this hill an estimated c 21m of drop, which is sufficient for it to be classified as a Sub-Trichant. 

 

The full details for the hill are: 

Group:  Mynydd Mallaen 

Name:  Pigyn Shôn Nicolas 

OS 1:50,000 map:  146

Summit Height:  322m (spot height)                                                           

Summit Grid Reference:  SN 66753 35404 & SN 66689 34767 (spot height) 

Bwlch Height:  c 301m (interpolation) 

Bwlch Grid Reference:  SN 67137 35439 (interpolation) 

Drop:  c 21m (spot height summit and interpolated bwlch) 

 

Myrddyn Phillips (June 2023)

 

 

 

 

 

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

 

Soil Hill (SE 076 313) 

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 conducted by Myrddyn Phillips. 

LIDAR image of Soil Hill (SE 076 313)

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 Soil Hill, and it is adjoined to the Pendle group of hills, which are situated in the southern Pennines, and it is positioned with the B6145 road to its north north-west, the A629 road to its west, a minor road to its south and the A644 road to its north-east, and has the town of Denholme towards the north. 

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 402m summit height, with an accompanying note stating; 402m summit height taken from the 1,320.4ft (402.46m) surface height on the OS Six-Inch map published in 1852. 

Extract from the Ordnance Survey series of Six-Inch maps

However, due to quarrying activity the height of this hill was in flux.  Therefore, 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 Soil Hill (SE 076 313)

LIDAR analysis gives the highest ground on this hill as 408.8m positioned at SE 07680 31368, 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 408.8m and this was derived from LIDAR analysis, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, and is 6.8m higher than the previously listed 402m summit height, which appeared as a 1,320.4ft (402.46m) surface height on the Ordnance Survey Six-Inch map published in 1852. 

 

The full details for the hill are:

Group:  Pendle

Name:  Soil Hill

OS 1:50,000 map:  104

Summit Height (New Height):  408.8m (LIDAR)

Summit Grid Reference:  SE 07680 31368 (LIDAR)

Col Height:  348.6m (LIDAR)

Col Grid Reference:  SE 06547 31672 (LIDAR)

Drop:  60.2m (LIDAR)

 

Myrddyn Phillips and Aled Williams (June 2023)

 

Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

Pen y Castell (SH 724 688) – 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 a combination of an optical level survey conducted by Graham Jackson and Myrddyn Phillips, a Leica RX1250 survey conducted by Alan Dawson and LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pen y Castell (SH 724 688)

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 Myrddyn Phillips and Aled Williams

The name the hill is listed by is Pen y Castell and it is adjoined to the Carnedd Llywelyn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with a minor road to its east north-east, and the B5106 road and the A470 road farther to its east, and has the village of Llanbedrycennin towards the east.

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

The summit of this hill was surveyed by optical level from its near higher summit on the 9^th April 2010 by Graham Jackson and Myrddyn Phillips and determined to be 2.43m lower.  The higher summit positioned at SH 72187 68880 was subsequently surveyed by Alan Dawson using a Leica RX1250 on the 14^th June 2017, resulting in a 623.516m summit height.  Therefore, the lower summit relative to the higher is 621.086m in height.

However, it was not until LIDAR became available that the bwlch 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 an optical level survey, a Leica RX1250 survey and LIDAR analysis, resulting in a 621.1m summit height and a 611.0m bwlch height, with these values giving this hill 10.0m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

                                                                                                                                      

The full details for the hill are: 

Group:  Carnedd Llywelyn

Name:  Pen y Castell

OS 1:50,000 map:  115

Summit Height:  621.1m (relative to optical level survey [2.43m lower] from 623.5m higher summit)

Summit Grid Reference:  SH 72434 68874 (LIDAR)

Bwlch Height:  611.0m (LIDAR)

Bwlch Grid Reference:  SH 72374 68895 (LIDAR)   

Drop:  10.0m (relative to optical level survey [2.43m lower] from 623.5m higher summit and LIDAR bwlch) 

 

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 (June 2023)

 

 

 

  

Mapping Mountains – Significant Name Changes – 100m Twmpau

Pt. 102.2m (SM 886 395) 

There has been a Significant Name Change to a hill that is listed in the 100m 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 Pt. 102.2m (SM 886 395)

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

100m Twmpau – Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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 100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Garn Fawr group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with the coast to its north, west and south, and minor roads to its east and south-east, with the A487 road farther to its south-east, and has the town of Abergwaun (Fishguard) towards the east south-east.

The hill appeared in the original Welsh 100m P30 list on Geoff Crowder’s v-g.me website, under the invented and transposed name of Banc-y-Pant-y-beudy, with an accompanying note stating; Name from buildings to the East.

Banc-y-Pant-y-beudy

103m

SM887395

157

35

Name from buildings to the East

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 farm and add the words Banc-y- 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

However, on occasion even when research is conducted an appropriate name for the hill may not be found, and on such occasions the listing protocol is to use the point (Pt. 102.2m) notation, and for this hill this is such an example.

Therefore, the name this hill is now listed by in the 100m Twmpau is Pt. 102.2m, and this is being used as the author has not found an appropriate name for the hill either through historic research and/or local enquiry. 

 

The full details for the hill are:

Group:  Garn Fawr

Name:  Pt. 102.2m

Previously Listed Name:  Banc-y-Pant-y-beudy   

OS 1:50,000 map:  157

Summit Height:  102.2m (LIDAR) 

Summit Grid Reference:  SM 88697 39503 (LIDAR) 

Bwlch Height:  71.4m (LIDAR) 

Bwlch Grid Reference:  SM 88963 39549 (LIDAR) 

Drop:  30.8m (LIDAR) 

 

Myrddyn Phillips (June 2023)