Monthly Synopsis

 

Synopsis of all major changes detailed on Mapping Mountains during the last calendar month.  These can include new, confirmation and retrospective changes

 

Hill Reclassifications: 

Creigiau Cochion (SH 756 835) - 100m Sub-Twmpau addition

Cae War y Coed (SN 927 456) - 200m Sub-Twmpau addition

Fallw (SH 785 792) - 100m Sub-Twmpau reclassified to 30-99m Sub-Twmpau

Carreg Rhoson (SM 672 256) - Dominant deletion

Craig Rofft (SH 776 831) - 100m Sub-Twmpau deletion

Pt. 181.4m (SN 731 303) - Welsh Sub-P15 reclassified to Welsh P15

Pen y Dinas (SH 779 829) - 100m Sub-Twmpau deletion

Allt y Geifr (SN 762 284) - Welsh P15 reclassified to Welsh Sub-P15

Mynydd Trallwng (SN 965 311) - Sub-Trichant deletion

Safle Claddu Nant y Caws (SN 468 174) & (SN 469 174) and Cae Mawr (SN 462 175) - Lesser Dominant reclassified to Dual Summit Lesser Dominant

Pt. 112.3m (SH 807 793) - 100m Sub-Twmpau deletion

 

 

Significant Height Revisions: 

Cefn Gwrhyd (SN 737 096) - The Welsh P15s

Bryn (SH 782 798) - 30-99m Twmpau

Allt y Geifr (SN 762 284) - The Welsh P15s

 

 

Summit Relocations: 

Pt. 364.9m (SN 901 346) - Y Trichant - The 300m Hills of Wales

Mynydd Bwlch y Groes (SN 868 356) - Y Pedwarau - The 400m Hills of Wales

Cefn Gwrhyd (SN 737 096) - The Welsh P15s

Cae Twyn Pellaf (SN 935 497) - 200m Twmpau

 

Significant Name Changes: 

Creigiau Cochion (SH 756 835) - 100m Twmpau

Cae War y Coed (SN 927 456) - 200m Twmpau

Pt. 364.9m (SN 901 346) - Y Trichant - The 300m Hills of Wales

Fallw (SH 785 792) - 30-99m Twmpau

Great Trefgarn Mountain (SM 944 243) - 100m Twmpau and Y Trechol - The Dominant Hills of Wales

Gwar Alltyfron (SN 998 494) - Y Trichant - The 300m Hills of Wales

Penllwyngwyn Mawr (SN 549 007) - 30-99m Twmpau and Y Trechol - The Dominant Hills of Wales

Cae Twyn Pellaf (SN 935 497) - 200m Twmpau

Bryn (SH 782 798) - 30-99m Twmpau

Prysiau Fawr (SN 914 481) - 200m Twmpau

Mapping Mountains – Significant Name Changes – 200m Twmpau

Prysiau Fawr (SN 914 481) 

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 LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Prysiau Fawr (SN 914 481)

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. 

200m Twmpau by Myrddyn Phillips

The hill is adjoined to the Drygarn Fawr 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 and south-east, and the A483 road to its north-east and west, and has the town of Llanwrtyd towards the west south-west.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill appeared under the invented and transposed name of Bryn Prysiau, with an accompanying note stating; Name from buildings to the North-West.

Bryn Prysiau

240m

SN914481

147

188

Name from buildings to the North-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.  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 384 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 a part of Prysiau Fawr farm in the apportionments, with the details on the Tithe map appearing in the parish of Llangamarch, and in the county named as Brecon. 

Extract from the apportionments

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

 

The full details for the hill are:

Group:  Drygarn Fawr

Name:  Prysiau Fawr

Previously Listed Name:  Bryn Prysiau   

OS 1:50,000 map:  147

Summit Height:  239.5m (LIDAR) 

Summit Grid Reference:  SN 91406 48141 (LIDAR) 

Bwlch Height:  214.8m (LIDAR) 

Bwlch Grid Reference:  SN 91321 48369 (LIDAR) 

Drop:  24.7m (LIDAR) 

 

Myrddyn Phillips (June 2024)

 

 

 

 

 

  

Mapping Mountains – Significant Height Revisions – The Welsh P15s

Allt y Geifr (SN 762 284) 

There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, 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 Allt y Geifr (SN 762 284)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is listed by is Allt y Geifr, and it is adjoined to the Mynydd Du group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned encircled by minor roads with the A4069 road farther to its north-west and south-west, and has the village of Llangadog towards the west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with an estimated c 16m of drop, based on the 174m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated c 158m bwlch height, based on interpolation of 5m contouring between 155m – 160m that appeared on the OS Maps website. 

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 Allt y Geifr (SN 762 284)

The summit height produced by LIDAR analysis is 171.1m and when compared to detail on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, 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 171.1m and this was derived from LIDAR analysis.  This is 2.9m lower than the 174m spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage. 

 ills of Wales, and are reproduced below@

The full details for the hill are: 

Group:  Mynydd Du 

Name:  Allt y Geifr 

OS 1:50,000 map:  146, 160

Summit Height (New Height):  171.1m (LIDAR)                                                           

Summit Grid Reference:  SN 76221 28491 (LIDAR) 

Bwlch Height:  156.9m (LIDAR) 

Bwlch Grid Reference:  SN 76558 28873 (LIDAR) 

Drop:  14.2m (LIDAR) 

 

Myrddyn Phillips (June 2024)

 

 

  

Mapping Mountains – Hill Reclassifications – 100m Twmpau

 

Pt. 112.3m (SH 807 793) – 100m Sub-Twmpau deletion

There has been a deletion from the list of 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. 112.3m (SH 807 793)

The criteria for the list that this deletion 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. 

100m Twmpau by Myrddyn Phillips

The hill is being listed by the point (Pt. 112.3m) notation as an appropriate name for it either through local enquiry and/or historic research has not been found by the author, and it is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned encircled by minor roads, with the A470 road farther to its west and the A55 road farther to its south-east, and has the town of Llandudno towards the north-west.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the Hills to be surveyed sub list with a non-interpolated c 120m summit height.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 25m of drop, based on an estimated c 123m summit height and an estimated c 98m bwlch height, with the summit height based on interpolation of the uppermost 120m ring contour that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website 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 that was 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 Magic Maps and WalkLakes 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 for this hill it has a 112m summit spot height. 

Extract from the interactive mapping hosted on the WalkLakes website

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 deletion of this hill from 100m Sub-Twmpau status is due to LIDAR analysis, resulting in a 112.3m summit height and a 98.6m bwlch height, with these values giving this hill 13.8m of drop, which is insufficient for it to be classified as a 100m Sub-Twmpau. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Pt. 112.3m 

OS 1:50,000 map:  116

Summit Height:  112.3m (LIDAR) 

Summit Grid Reference:  SH 80726 79335 (LIDAR) 

Bwlch Height:  98.6m (LIDAR) 

Bwlch Grid Reference:  SH 80692 79102 (LIDAR) 

Drop:  13.8m (LIDAR) 

 

Myrddyn Phillips (June 2024)

 

 

Mapping Mountains – Hill Reclassifications – Y Trechol – The Dominant Hills of Wales

Safle Claddu Nant y Caws (SN 468 174) & (SN 469 174) and Cae Mawr (SN 462 175) – Lesser Dominant reclassified to Dual Summit Lesser Dominant

There has been confirmation of a reclassification to the list of the 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 LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Cae Mawr (SN 462 175) and Safle Claddu Nant y Caws (SN 468 174 & SN 469 174)

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

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

Dual Summit hills:

A hill classified as a Dual Summit is defined as one which has an extant natural summit coupled with that of a higher artificial summit, with the latter that can be described as stable in character.  In the main, these recent man-made constructions are the result of quarrying activities producing spoil tips, or as in this instance a landfill.  These recent man-made constructions are treated differently to ancient man-made constructions such as hill forts and tumuli, as if the latter are deemed stable and of an earthen character their age dictates that they can be viewed as being permanent in nature and are now effectively a part of the hill.  For those bagging Dual Summit hills, a visit to either the natural high point or the elevated man-made high point is sufficient to claim an ascent of the hill.  With the Dual Summit classification being a relatively new category and fist instigated in January 2018 for a Dual Summit Pedwar. 

The name the hill is now listed by is Safle Claddu Nant y Caws for the higher man-made summit and Cae Mawr for the lower natural summit, and it 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 the two summits are positioned with the A48 road to their north and a minor road to their south-west, and has the town of Caerfyrddin (Carmarthen) towards the north-west. 

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, the natural summit was included in the main P30 list with a 155m summit height, based on the spot height adjoined to a triangulation pillar positioned at SN 46405 17608 that appears 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

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 then separated in to its two component parts, with the man-made summit listed with an estimated c 59m of drop, based on an estimated c 156m summit height and an estimated c 97m bwlch height, with both heights based on interpolation of 5m contouring that appeared on the interactive mapping hosted on the OS Maps website.  With the lower natural summit listed with a 155 summit height and the bwlch between these two summits estimated as c 138m, which if separating these hills would give an estimated c 17m of drop.

However, it was not until LIDAR became available that the details for these summits 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 reclassification of this hill to Dual Summit Lesser Dominant status is due to LIDAR analysis, resulting in a 163.8m summit height for the man-made summit and a 155.1m summit height for the natural summit, and a 98.5m bwlch height, with these values giving the man-made summit 65.3m of drop and 39.89% dominance and the natural summit 56.6m of drop and 36.50% dominance, which is sufficient for Dual Summit Lesser Dominant status, with the details for the higher summit prioritised within the list. 

 

The full details for the hill are:

Group:  Mynydd Sylen

Name:  Safle Claddu Nant y Caws (artificial Dual Summit) and Cae Mawr (natural Dual Summit)

OS 1:50,000 map:  159

Summit Height:  163.8m (artificial Dual Summit) and 155.1m (natural Dual Summit) (LIDAR)

Summit Grid Reference:  SN 46899 17416 & SN 46900 17411 (artificial Dual Summit) and SN 46268 17566 (natural Dual Summit) (LIDAR)

Bwlch Height:  98.5m (LIDAR)

Bwlch Grid Reference:  SN 39491 11374 & SN 39493 11375 (LIDAR)

Drop:  65.3m (artificial Dual Summit) and 56.6m (natural Dual Summit) (LIDAR)

Dominance:  39.89% (artificial Dual Summit) and 36.50% (natural Dual Summit) (LIDAR)

 

Myrddyn Phillips (June 2024)