Mapping Mountains – Significant Height Revisions – 100m Twmpau

 

Coed Uchaf (SJ 232 683) 

There has been a Significant Height Revision 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 detail produced by JoeNuttall in his surface analysis programme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Myrddyn Phillips. 

LIDAR image of Coed Uchaf (SJ 232 683)

The criteria for the list that this height revision 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 name the hill is now listed by is Coed Uchaf, and it 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 encircled by minor roads, with the A55 road farther to its north, the B5123 road farther to its west, the A541 road farther to its south and the A5119 road farther to its east, and has the town of Y Fflint (Flint) towards the north.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a summit height of c 160m positioned at SJ 232 686, based on the uppermost non-interpolated ring contour that appears on the contemporary Ordnance Survey 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.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated against the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.  This mapping had many spot heights not on other publicly available maps and for this hill it had a 162m summit spot height positioned at SJ 23209 68591.

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 Coed Uchaf (SJ 232 683)

The height produced by LIDAR analysis to the summit of this hill is 161.7m positioned at SJ 23205 68344 as opposed to the 160.5m LIDAR height positioned at SJ 23205 68597.  This relocated summit position is not given an uppermost 160m ring contour on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and this height 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 161.7m and this was derived from LIDAR analysis, this is 1.7m higher than the originally listed summit height of a non-interpolated c 160m and 0.3m lower than the 162m spot height that was positioned at SJ 23209 68591 on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Moel y Gamelin 

Name:  Coed Uchaf 

OS 1:50,000 map:  117

Summit Height (New Height):  161.7m (LIDAR) 

Summit Grid Reference:  SJ 23205 68344 (LIDAR) 

Bwlch Height:  132.6m (LIDAR) 

Bwlch Grid Reference:  SJ 23101 68383 (LIDAR) 

Drop:  29.1m (LIDAR) 

 

Myrddyn Phillips (January 2024)

Mapping Mountains – Summit Relocations – The Fours – The 400m Hills of England

 

Wood Barrow (SS 716 425) 

There has been a Summit Relocation 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 Wood Barrow (SS 716 425)

The criteria for the list that this summit relocation 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 are three categories of sub hills, with this hill being included in the 400m Sub-Four category, the criteria for which are all English 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 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 Wood Barrow, and it is adjoined to the Dunkery Beacon group of hills, which are situated in the counties of Somerset and Devon, and it is positioned with the A39 road to its north-west and the B3358 road to its south, and has the small community of Parracombe towards the west north-west.

When the 1^st edition of the The Fours was published by Europeaklist in December 2013, the qualifying 400m Sub-Four hill was listed as Wood Barrow (SS 716 425) with 22m of drop, based on the 480m summit spot height that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 458m col spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating:

Although Chapman Barrows at SS 700 434 has a 480m map height, it is not listed as a twin Sub-Four as its 480.093m flush bracket height means ground at the base of the trig pillar will be below 480m. 

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 image of Chapman Barrows (SS 700 434) and Wood Barrow (SS 716 425)

The height produced by initial LIDAR analysis to the high point of Chapman Barrows is 479.8m positioned at SS 70003 43472 and to the high point of Wood Barrow is 479.7m positioned at SS 71627 42506, resulting in the summit of the qualifying 400m Sub-Four being relocated from Wood Barrow to Chapman Barrows. 

LIDAR summit image of Wood Barrow (SS 716 425)

However, the latest available LIDAR analysis gives the high point of Chapman Barrows as 479.8m positioned at SS 70003 43471 and the high point of Wood Barrow as 480.0m positioned at SS 71627 42505, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit 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 height produced by the latest available LIDAR analysis to the summit of Wood Barrow is 480.0m and this is positioned at SS 71627 42505.  This position is adjacent to where the 480m spot height appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and is approximately 1.8km south-eastward from the summit of Chapman Barrows which LIDAR gives as 0.2m lower.

 

The full details for the hill are:

Group:  Dunkery Beacon

Name:  Wood Barrow

OS 1:50,000 map:  180

Summit Height:  480.0m (LIDAR)

Summit Grid Reference (New Position):  SS 71627 42505 (LIDAR)

Col Height:  457.7m (LIDAR)

Col Grid Reference:  SS 72621 42582 (LIDAR)

Drop:  22.3m (LIDAR)

 

Myrddyn Phillips and Aled Williams (January 2024)

 

 

 

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

Pt. 395.2m (SN 847 436) 

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 LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pt. 395.2m (SN 847 436)

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 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 hill is adjoined to the Mynydd Epynt group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with the A483 road to its immediate north-west, and has the town of Llanwrtyd towards the north-east.

The hill appeared in the original 300m height band of Welsh P30 hills published on Geoff Crowder’s v-g.me website, under the invented and transposed name of Moel Bylchau, with an accompanying note stating; Name from buildings to the West.

Moel Bylchau

396m

SN847436

147/160

187

Clem/Yeaman. Name from buildings to the 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

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. 395.2) notation, and for this hill this is such an example.

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Pt. 395.2m, 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:  Mynydd Epynt 

Name:  Pt. 395.2m 

Previously Listed Name:  Moel Bylchau 

OS 1:50,000 map:  147, 160

Summit Height:  395.2m (LIDAR)                                                           

Summit Grid Reference:  SN 84736 43625 & SN 84737 43623 (LIDAR) 

Bwlch Height:  281.85m (LIDAR) 

Bwlch Grid Reference:  SN 86057 40451 (LIDAR) 

Drop:  113.4m (LIDAR) 

 

Myrddyn Phillips (January 2024)

 

  

Mapping Mountains – Hill Reclassifications – 100m Twmpau

Coed Uchaf (SJ 232 683) – 100m Twmpau reclassified to 100m Sub-Twmpau

There has been a reclassification to the list of 100m 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 Coed Uchaf (SJ 232 683)

The criteria for the list that this reclassification 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 name the hill is now listed by is Coed Uchaf, and it 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 encircled by minor roads, with the A55 road farther to its north, the B5123 road farther to its west, the A541 road farther to its south and the A5119 road farther to its east, and has the town of Y Fflint (Flint) towards the north.

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, as it was considered not to meet the criteria then used for the main P30 category. 

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.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated against the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.  This mapping had many spot heights not on other publicly available maps and for this hill it had a 162m summit spot height positioned at SJ 23209 68591 and with an estimated c 132m bwlch height based on interpolation of 5m contouring between 130m – 135m, these values gave this hill an estimated c 30m of drop and therefore it was reclassified to 100m Twmpau status.

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 reclassification of this hill to 100m Sub-Twmpau status is due to LIDAR analysis, resulting in a 161.7m summit height and a 132.6m bwlch height, with these values giving this hill 29.1m of drop, which is insufficient for it to be classified as a 100m Twmpau. 

 

The full details for the hill are: 

Group:  Moel y Gamelin 

Name:  Coed Uchaf 

OS 1:50,000 map:  117

Summit Height:  161.7m (LIDAR) 

Summit Grid Reference:  SJ 23205 68344 (LIDAR) 

Bwlch Height:  132.6m (LIDAR) 

Bwlch Grid Reference:  SJ 23101 68383 (LIDAR) 

Drop:  29.1m (LIDAR) 

 

Myrddyn Phillips (January 2024)

 

  

Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

 

Clipiau Duon (SH 900 227) – 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 Clipiau Duon (SH 900 227)

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 Clipiau Duon 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 the A494 road to its north-west and a minor road to its east, and has the village of Llanymawddwy towards the south.

When the initial P10 sub list was completed in June 2020 this hill was listed with an estimated c 9m of drop, based on an estimated c 585m summit height and an estimated c 576m bwlch height, with both heights 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 586.3m summit height and a 576.1m bwlch height, with these values giving this hill 10.2m of drop, which is sufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Esgeiriau Gwynion

Name:  Clipiau Duon      

OS 1:50,000 map:  125

Summit Height:  586.3m (LIDAR)

Summit Grid Reference:  SH 90074 22779 (LIDAR)

Bwlch Height:  576.1m (LIDAR)

Bwlch Grid Reference:  SH 89864 22477 (LIDAR)   

Drop:  10.2m (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 (January 2024)