Sunday, 4 June 2023

Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru


Pt. 563.3m (SH 638 551) – 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 Pt. 563.3m (SH 638 551)

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 hill is being listed by the point (Pt. 563.3m) notation and it is adjoined to the Yr Wyddfa group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the A4086 road to its north and the A498 road to its east, and has the village of Llanberis towards the north-west.

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

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.  With initial LIDAR analysis giving the drop of this hill close to 10.0m and this has now been confirmed with latest available LIDAR.

Therefore, the addition of this hill to Welsh Highland Sub status is due to LIDAR analysis, resulting in a 563.3m summit height and a 553.2m 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:  Yr Wyddfa

Name:  Pt. 563.3m

OS 1:50,000 map:  115

Summit Height:  563.3m (LIDAR)

Summit Grid Reference:  SH 63821 55162 (LIDAR)

Bwlch Height:  553.2m (LIDAR)

Bwlch Grid Reference:  SH 63750 55176 (LIDAR)   

Drop:  10.0m (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 (June 2023)

 

 

 

  

Saturday, 3 June 2023

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


Hawkshead (SD 633 603) – 400m Sub-Four deletion

There has been a deletion 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 Hawkshead (SD 633 603)

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

The FoursThe 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 deleted from 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 2nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24th April 2018.

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

The name the hill is listed by is Hawkshead and it is adjoined to the Ward’s Stone group of hills, which are situated in the southern Pennines, and it is positioned with a minor road to its north-west and north north-east, the B6480 road farther to its north and the A683 road farther to its north-west, and has the town of High Bentham towards the north.

When the 2nd edition of the The Fours – The 400m Hills of England was published by Mapping Mountains Publications in April 2018, the hill was included as a 400m Sub-Four and listed with an estimated c 20m of drop, based on the 408m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 388m col height based on interpolation of 10m contouring between 380m – 390m. 

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 Hawkshead

LIDAR col image of Hawkshead

Therefore, the deletion of this hill from 400m Sub-Four status is due to LIDAR analysis, resulting in a 407.2m summit height and a 389.8m col height, with these values giving this hill 17.4m of drop, which is insufficient for it to be classified as a 400m Sub-Four.

 

The full details for the hill are:

Group:  Ward’s Stone

Name:  Hawkshead

OS 1:50,000 map:  97

Summit Height:  407.2m (LIDAR)

Summit Grid Reference:  SD 63395 60302 (LIDAR)

Col Height:  389.8m (LIDAR)

Col Grid Reference:  SD 63762 59950 (LIDAR)

Drop:  17.4m (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 1st edition of this list by Europeaklist please consult the following Change Registers:

 

The Fours

 

The Fours – 400m Sub-Four

 

The Fours – 390m Sub-Four

 

The Fours – 390m Double Sub-Four

 

Myrddyn Phillips and Aled Williams (June 2023)

  

Friday, 2 June 2023

Mapping Mountains – Summit Relocations – 100m Twmpau


Parc Ffynnon (SN 199 192 & SN 200 192) 

There has been a Summit Relocation 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 Parc Ffynnon (SN 199 192 and SN 200 192)

The criteria for the list that this summit relocation 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 Parc Ffynnon and this was derived from the Tithe map, and it is adjoined to the Mynydd Preseli group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its west and east, and the A40 road to its south, and has the town of Hendy-gwyn ar Daf (Whitland) towards the south.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with an estimated c 145m summit height, based on interpolation of its uppermost 145m ring contour positioned at SN 20102 19284 that appears on the contemporary 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.

LIDAR analysis gives the highest ground on this hill as 143.7m positioned at SN 20028 19265.  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 Parc Ffynnon (SN 199 192 and SN 200 192) 

The height produced by LIDAR analysis to the natural summit of this hill is 143.6m and is positioned at SN 19998 19263 and SN 20001 19261 and SN 20005 19264, 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, 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 judged to be 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 LIDAR analysis to the natural summit of this hill is 143.6m and is positioned at SN 19998 19263 and SN 20001 19261 and SN 20005 19264, 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 approximately 105 metres westward from where the uppermost 145m contour ring appears on the contemporary Ordnance Survey 1:25,000 Explorer map, and approximately 25 metres westward from where the high point of the raised field boundary is positioned.

 

The full details for the hill are: 

Group:  Mynydd Preseli 

Name:  Parc Ffynnon 

OS 1:50,000 map:  158

Summit Height:  143.6m (LIDAR) 

Summit Grid Reference (New Position):  SN 19998 19263 & SN 20001 19261 & SN 20005 19264 (LIDAR) 

Bwlch Height:  98.0m (LIDAR) 

Bwlch Grid Reference:  SN 19882 19602 & SN 19884 19603 (LIDAR) 

Drop:  45.6m (LIDAR) 

 

Myrddyn Phillips (June 2023)

 

 

  

Thursday, 1 June 2023

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

 

Foel Blaen Rhisglog (SN 696 468) 

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 detail on contemporary maps produced from Ordnance Survey data. 

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 13th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Esgair Wen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with as minor road to its south, the B4343 road to its north-west and the A482 road to its south-west, and has the town of Llanbedr Pont Steffan (Lampeter) towards the west.

The hill appeared in the original 300m height band of Welsh P30 hills published on Geoff Crowder’s v-g.me website, under the transposed name of Blaen Rhisglog Plantation, which is a prominent name that appears close to the summit of this hill on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.


Blaen Rhisglog Plantation375mSN696468146187/199


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 PenBryn or Moel in front of them or as in this instance transpose the name of a conifer plantation and use it for that of the hill.  If a more appropriate name can be found 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 a more appropriate name for the hill can usually be found.

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, and it is the series of Ordnance Survey Six-Inch maps that form the basis of the change in the listed name of this hill.

The Ordnance Survey series of Six-Inch maps formed the base map Ordnance Survey used for many decades leading to the production of the 1:10,000 Series of maps, both have now been superseded by the digitised Master Map.  The series of Six-Inch maps are excellent for name placement and especially so compared to the contemporary Ordnance Survey 1:25,000 Explorer map, and it is the series of Six-Inch maps that have the name of Foel Blaen Rhisglog adjacent to the summit of this hill. 

Extract from the Ordnance Survey series of Six-Inch maps

The name of Blaen Rhisglog Plantation and that of Foel Blaen Rhisglog are associated with the farm of Blaen-rhisglog which is positioned to the south of the hill.  In this instance a hill name is favoured over that of a plantation name.

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Foel Blaen Rhisglog and this was derived from the Ordnance Survey series of Six-Inch maps. 

 

The full details for the hill are: 

Group:  Esgair Wen 

Name:  Foel Blaen Rhisglog 

Previously Listed Name:  Blaen Rhisglog Plantation 

OS 1:50,000 map:  146

Summit Height:  375m (spot height)                                                           

Summit Grid Reference:  SN 69640 46891 (spot height) 

Bwlch Height:  c 323m (interpolation) 

Bwlch Grid Reference:  SN 70311 47304 & SN 70414 47322 (interpolation) 

Drop:  c 52m (spot height summit and interpolated bwlch) 

 

Myrddyn Phillips (June 2023)

 

Wednesday, 31 May 2023

Mapping Mountains – Significant Height Revisions – Welsh Highlands – Uchafion Cymru


Llechwedd Du (SH 893 446) 

There has been a Significant Height Revision to a hill that is listed in 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 for the Welsh Highlands – Uchafion Cymru list authored by Aled Williams and Myrddyn Phillips. 

LIDAR image of Llechwedd Du (SH 893 446)

The criteria for the list that this height revision 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 Llechwedd Du and it is adjoined to the Carnedd y Filiast group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A2), and is positioned with the A4212 road to its south and the B4501 road to its east, and has the town of Y Bala towards the south south-east and the village of Cerrigydrudion towards the north-east. 

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

When the original list that later became known as the Welsh Highlands – Uchafion Cymru was first compiled, this hill was included as a Welsh Highland Sub with 14m of drop, based on the 509m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 495m bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

The details for this hill were re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and had contours at 5m intervals which were consistently more accurate compared to the 5m contours that sometimes appeared on Ordnance Survey 1:25,000 Explorer maps and the online Vector Map Local.  This re-assessment resulted in its reclassification to Welsh Highland P15 status and listed with an estimated c 16m of drop, based on an estimated c 511m summit height from interpolation of the 510m uppermost contour and the 495m bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer map. 

Extract from the interactive mapping hosted on the OS Maps 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.

LIDAR analysis gives the highest ground on this hill as 511.4m positioned at SH 89360 44629, 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 511.4m and this was derived from LIDAR analysis, this is positioned at SH 89360 44629 and is 2.4m higher than its originally listed height of 509m, which was based on the summit spot height that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Carnedd y Filiast

Name:  Llechwedd Du

OS 1:50,000 map:  124, 125

Summit Height (New Height):  511.4m (LIDAR)

Summit Grid Reference:  SH 89360 44629 (LIDAR)

Bwlch Height:  497.1m (LIDAR)

Bwlch Grid Reference:  SH 89096 44273 (LIDAR)   

Drop:  14.3m (LIDAR) 

 

Myrddyn Phillips and Aled Williams (May 2023)