Mapping Mountains - Hill Reclassifications - Y Pedwarau - The 400m Hills of Wales

Y Pedwarau – Hill Reclassifications

Y Pedwarau are the Welsh hills at or above 400m and below 500m in height that have a minimum drop of 30m.  Accompanying the main P30 list are five sub lists; these are the 500m Sub-Pedwar, 500m Double Sub-Pedwar, 400m Sub-Pedwar, 390m Sub-Pedwar and 390m Double Sub-Pedwar category’s, with their criteria detailed in the respective Change Registers that have been created and which are linked in their above titles, with the Introduction to this list being linked in the above title.

The list is co-authored by Myrddyn Phillips and Aled Williams and the posts that have appeared on Mapping Mountains detailing the additions, reclassifications and deletions to the main P30 list and the sub lists appear below presented chronologically in receding order.

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Esgair Wen (SN 807 664) – 400m Sub-Pedwar reclassified to Pedwar (105th reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m 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 Aled Williams. 

LIDAR image of Esgair Wen (SN 807 664)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list isco-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Esgair Wen and it is adjoined to the Drygarn Fawr group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north-west, west south-west and  east south-east, and has the village of Pontrhydfendigaid towards the west.

When the original 400m height band of Welsh P30 hills was 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.

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 30m of drop, based on the 496m summit spot height that appeared on the contemporary Ordnance Survey 1:25,000 Explorer map, and an estimated c 466m bwlch height, based on interpolation of 10m contouring between 460m – 470m. 

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.

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps and for this hill it had a 465m bwlch spot height, and when coupled with its 496m summit spot height these values gave this hill 31m of drop, and these are the values given this hill when the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013.

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.

The details for this hill were analysed using what is now the archived Welsh LIDAR, resulting in a 494.6m summit height and a 464.7m bwlch height, with these values giving this hill 29.9m of drop and therefore it was reclassified to 400m Sub-Pedwar status.

However, new Welsh LIDAR has now been used to analyse the details for this hill, resulting in a 494.8m summit height and a 464.8m bwlch height, with these values giving this hill 30.0m of drop, which is sufficient for it to be reinstated to Pedwar status. 

 

The full details for the hill are:

Group:  Drygarn Fawr 

Name:  Esgair Wen 

OS 1:50,000 map:  135, 136, 147

Summit Height:  494.8m (LIDAR) 

Summit Grid Reference:  SN 80767 66474 (LIDAR) 

Bwlch Height:  464.8m (LIDAR) 

Bwlch Grid Reference:  SN 80123 66302 (LIDAR) 

Drop:  30.0m (LIDAR)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (September 2023)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Titli (SN 933 757) – 400m Sub-Pedwar addition (104th reclassification)

Survey post for Bryn Titli

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and detail produced by Joe Nuttall in his surface analysis progamme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Myrddyn Phillips. 

Bryn Titli (SN 933 757)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Bryn Titli and it is adjoined to the Hirddywel group of hills, which are situated in the north-easterly part of South Wales (Region B, Sub-Region B2), and it is positioned with the A470 road to its west and a minor road and the B4518 road to its east, and has the village of Llangurig towards the north north-west.

When the original 400m height band of Welsh P30 hills was 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. 

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 listed with 19m of drop, based on the 493m summit spot height and the 474m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on Geograph website and which was entitled the Interactive Coverage Map. 

The Trimble GeoXH 6000 gathering data at the summit of Bryn Titli

Subsequently this hill was surveyed with the Trimble GeoXH 6000 on the 12.03.16, resulting in a 492.7m summit height positioned at SN 93383 75719 and a 472.7m bwlch height positioned at SN 93214 76009, with these values giving this hill 19.97m of drop. 

The Trimble GeoXH 6000 set-up position at the bwlch of Bryn Titli

However, it was not until LIDAR became available that the details for this hill relative to the data produced by the Trimble GeoXH 6000 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 a 493.0m summit height positioned at SN 93382 75719 and a 473.0m bwlch height positioned at SN 93192 76017, with these values giving this hill 20.1m of drop. 

LIDAR image of Bryn Titli (SN 933 757)

Since the survey of these hills, the LIDAR (Light Detection & Ranging) technique is now being used to produce accurate height and position for hills.  Therefore, numerical data produced by surveying with the Trimble GeoXH 6000 is being updated.  However, each individual data set is analysed and as data produced by the Trimble GeoXH 6000 is considered more accurate it is this relative to the position produced by LIDAR that is prioritised.

Therefore, the addition of this hill to 400m Sub-Pedwar status is due to a Trimble GeoXH 6000 survey and LIDAR analysis, resulting in a 492.7m summit height and a 472.7m bwlch height, with these values giving this hill 20.0m of drop, which is sufficient for it to be classified as a 400m Sub-Pedwar. 

 

The full details for the hill are:

Group:  Hirddywel 

Name:  Bryn Titli 

OS 1:50,000 map:  136, 147

Summit Height:  492.7m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SN 93383 75719 (Trimble GeoXH 6000) 

Bwlch Height:  472.7m (converted to OSGM15, height relative to Trimble GeoXH 6000) 

Bwlch Grid Reference:  SN 93192 76017 (LIDAR) 

Drop:  20.0m (Trimble GeoXH 6000 summit and LIDAR with height relative to Trimble GeoXH 6000 bwlch)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (August 2023)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Moel Wnog (SH 735 440) – Pedwar reclassified to 400m Sub-Pedwar (103rd reclassification)

Significant Height Revisions post for Moel Wnog

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, 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 progamme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Aled Williams and Myrddyn Phillips. 

LIDAR image of Moel Wnog (SH 735 440)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified to the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Moel Wnog and it is adjoined to the Arenig Fach group of hills, which are situated in the north-westerly part of North Wales (Region A, Sub-Region A2), and it is positioned with a minor road to its west, the A470 road farther to its west, the B4391 road to its south-west and the B4407 road to its south-east, and has the village of Ffestiniog towards the south-west.

When the original 400m height band of Welsh P30 hills was 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 29 of drop, based on an estimated c 468m summit height and an estimated c 439m bwlch height, with both heights based on interpolation of 10m contouring that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

Prior to the 1^st edition of the Y Pedwarau being published by Europeaklist in May 2013, the details for this hill were re-evaluated and it was listed as a Pedwar with an estimated c 34m of drop, based on the 473m summit spot height that appears on the Harvey 1:40,000 British Mountain Map and an estimated c 439m bwlch height.

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 400m Sub-Pedwar status is due to LIDAR analysis, resulting in a 471.3m summit height and a 441.5m bwlch height, with these values giving this hill 29.8m of drop, which is insufficient for it to be classified as a Pedwar. 

 

The full details for the hill are:

Group:  Arenig Fach 

Name:  Moel Wnog 

OS 1:50,000 map:  124

Summit Height:  471.3m (LIDAR) 

Summit Grid Reference:  SH 73522 44084 (LIDAR) 

Bwlch Height:  441.5m (LIDAR) 

Bwlch Grid Reference:  SH 73597 44355 (LIDAR) 

Drop:  29.8m (LIDAR)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (August 2023)

  

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Crin Fynydd (SO 178 605) – Pedwar reclassified to 400m Sub-Pedwar (102nd reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, 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 progamme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Aled Williams and Myrddyn Phillips. 

Crin Fynydd (SO 178 605)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified to the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Crin Fynydd and it is adjoined to the Fforest Glud group of hills, which are situated in the easterly part of South Wales (Region B, Sub-Region B3), and it is positioned with the A44 road to its south and a minor road to its south-east, and has the village of Maesyfed (New Radnor) towards the east.

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 468m summit height and a 438m bwlch height, with both heights based on the spot heights that appear on the Ordnance Survey 1:25,000 Explorer map, and this hill was subsequently listed with 30m of drop based on the above values when the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013. 

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 Crin Fynydd (SO 178 605)

Therefore, the reclassification of this hill to 400m Sub-Pedwar status is due to LIDAR analysis, resulting in a 467.3m summit height and a 438.3m bwlch height, with these values giving this hill 29.0m of drop, which is insufficient for it to be classified as a Pedwar. 

 

The full details for the hill are:

Group:  Fforest Glud 

Name:  Crin Fynydd 

OS 1:50,000 map:  148

Summit Height:  467.3m (LIDAR) 

Summit Grid Reference:  SO 17846 60534 & SO 17846 60536 & SO 17853 60534 (LIDAR) 

Bwlch Height:  438.3m (LIDAR) 

Bwlch Grid Reference:  SO 17865 60748 (LIDAR) 

Drop:  29.0m (LIDAR)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (August 2023)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Mynydd Fforest (SO 094 395) – 400m Pedwar reclassified to 390m Sub-Pedwar (101st reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, 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 progamme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Aled Williams and Myrddyn Phillips. 

Mynydd Fforest (SO 094 395)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified to the 390m Sub-Pedwar category.  The criteria for this sub category being all Welsh hills at or above 390m and below 400m in height that have 30m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Mynydd Fforest and it 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 a minor road to its west, south and north-east, with the A470 road farther to its east, and has the village of Erwyd (Erwood) towards the north.

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a summit height of 400m, based on the spot height adjoined to the triangulation pillar 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

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 63m of drop, based on the 400m summit spot height and an estimated c 337m bwlch height, based on interpolation of 10m contouring between 330m – 340m, and these were the values this hill was listed by when the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013. 

LIDAR summit image of Mynydd Fforest (SO 094 395)

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 from Pedwar status is due to LIDAR analysis, resulting in a 399.8m summit height and a 334.9m bwlch height, with these values giving this hill 65.0m of drop, with its height now sufficient for it to be classified as a 390m Sub-Pedwar. 

 

The full details for the hill are:

Group:  Mynydd Epynt 

Name:  Mynydd Fforest 

OS 1:50,000 map:  161

Summit Height:  399.8m (LIDAR) 

Summit Grid Reference:  SO 09495 39530 (LIDAR) 

Bwlch Height:  334.9m (LIDAR) 

Bwlch Grid Reference:  SO 07943 38253 (LIDAR) 

Drop:  65.0m (LIDAR)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (July 2023)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 415.1m (SO 072 065) – 400m Sub-Pedwar addition (100th reclassification)

There has been an addition to the listing of the Y Pedwarau – The 400m 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. 415.1m (SO 072 065)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The hill is being listed by the point (Pt. 415.1m) notation and it is adjoined to the Cefn yr Ystrad group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned with the A4060 road to its north-west and a minor road to its south, and has the town of Merthyr Tudful towards the west.

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was not included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

This hill is a recent man-made construction and has undergone extensive terra-forming in the interim between the original compilation of this list and nowadays when independent surveyors, the availability of LIDAR and more detailed online mapping all give opportunity for increased numerical accuracy.  However, due to quarrying activity no contours of note appear 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

However, it was not until LIDAR became available that the details for this hill were 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 Pt. 415.1m (SO 072 065)

Although it was LIDAR that first distinguished the validity of this hill it is worth making note of its details on other mapping.  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 a 374m, 384m and a 397m spot height appear in the vicinity of the summit of this hill. 

Extract from the interactive mapping hosted on the WalkLakes website

Another resource now available online is the interactive mapping hosted on the Welsh Government website and entitled the DataMapWales.  This mapping has 5m contours and its detail matches that produced from the OS Terrain 5 product, which compliments much of that produced from LIDAR, and for this hill it has an uppermost 415m ring contour. 

Extract from the interactive mapping entitled the DataMapWales

Therefore, the addition of this hill to 400m Sub-Pedwar status is due to LIDAR analysis, resulting in a 415.1m summit height and a 389.8m bwlch height, with these values giving this hill 25.3m of drop, which is sufficient for it to be classified as a 400m Sub-Pedwar. 

 

The full details for the hill are:

Group:  Cefn yr Ystrad 

Name:  Pt. 415.1m 

OS 1:50,000 map:  160

Summit Height:  415.1m (LIDAR) 

Summit Grid Reference:  SO 07212 06536 (LIDAR) 

Bwlch Height:  389.8m (LIDAR) 

Bwlch Grid Reference:  SO 07596 06528 (LIDAR) 

Drop:  25.3m (LIDAR)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (July 2023)

 

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Cefn Gwenffrwd (SN 740 486) – 400m Sub-Pedwar reclassified to Pedwar (99th reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, 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 progamme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Aled Williams and Myrddyn Phillips. 

LIDAR image of Cefn Gwenffrwd (SN 740 486)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Cefn Gwenffrwd and it 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 a minor road to its north and south, and has the village of Llanddewibrefi towards the north-west.

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 list.

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 26m of drop, based on the 422m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 396m bwlch height based on interpolation of 10m contouring between 390m – 400m. 

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

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, the details for this ill were re-evaluated and it was listed as a 400m Sub-Pedwar with 29m of drop, based on the 422m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 393m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage 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 reclassification of this hill from 400m Sub-Pedwar status is due to LIDAR analysis, resulting in a 422.7m summit height and a 392.4m bwlch height, with these values giving this hill 30.3m of drop, which is sufficient for it to be classified as a Pedwar. 

 

The full details for the hill are:

Group:  Esgair Wen 

Name:  Cefn Gwenffrwd 

OS 1:50,000 map:  146, 147

Summit Height:  422.7m (LIDAR) 

Summit Grid Reference:  SN 74078 48615 (LIDAR) 

Bwlch Height:  392.4m (LIDAR) 

Bwlch Grid Reference:  SN 74312 49157 (LIDAR) 

Drop:  30.3m (LIDAR)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (July 2023) 

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Stonewall Hill (SO 318 696) – 400m Sub-Pedwar addition (98th reclassification)

1st survey post for Stonewall Hill

2nd survey post for Stonewall Hill

Significant Height Revisions post for Stonewall Hill

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales under the classification of National Top status (for details relating to the concept of National Tops see separate post), with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams. 

Stonewall Hill (SO 318 696)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Stonewall Hill and it is adjoined to the Beacon Hill group of hills, which are situated in Mid and West Wales (Region B, Sub-Region B1), and it is positioned with the A4113 road to its north, a minor road to its immediate west and the B4355 road farther to its west, and has the town of Trefyclo (Knighton) towards the north-west.

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

Extract from the Ordnance Survey series of Six-Inch maps showing the course of the border

Extract from the Magic Maps website showing the course of the border

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was not included as the concept of National Tops had not been devised.  The hill was subsequently analysed using contemporary Ordnance Survey maps and LIDAR for height and drop.  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 Stonewall Hill (SO 318 696)

LIDAR analysis confirms this hill as over 400m in height, and as the summit has now been surveyed with the Trimble GeoXH 6000, it is this result that is being prioritised for listing purposes. 

Gathering data at the summit of Stonewall Hill

Therefore, the confirmation of the addition of this hill to 400m Sub-Pedwar status under the National Top classification is due to LIDAR analysis and a subsequent Trimble GeoXH 6000 survey, resulting in a 400.1m summit height and a 376.4m bwlch height, with these values giving this hill 23.8m of drop which is sufficient for it to be classified as a 400m Sub-Pedwar. 

 

The full details for the hill are:

Group:  Beacon Hill 

Name:  Stonewall Hill

OS 1:50,000 map:  137, 148

Summit Height:  400.1m (converted to OSGM15)

Summit Grid Reference:  SO 31823 69655

Bwlch Height:  376.4m (converted to OSGM15)

Bwlch Grid Reference:  SO 31273 70279

Drop:  23.8m

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Aled Williams and Myrddyn Phillips (October 2021)

 

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Hergest Ridge (SO 246 557) – Pedwar addition (97th reclassification)

Survey post for Hergest Ridge

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales under the classification of National Top status (for details relating to the concept of National Tops see separate post), with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams. 

Hergest Ridge (SO 246 557)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop.  The list is co-authored byMyrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Hergest Ridge and it is adjoined to the Gwaun Ceste group of hills, which are situated in the eastern part of Mid and West Wales (Region B, Sub-Region B1), and it is positioned with the A44 road to its north-east, the B4594 road to its west and a minor road to its south, and has the small village of Llanfair Llythynwg (Gladestry) towards the west south-west.

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

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was not included as the concept of National Tops had not been devised.  The hill was subsequently analysed using contemporary Ordnance Survey maps and LIDAR for height and drop.  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 Hergest Ridge (SO 246 557) 

LIDAR analysis confirms this hill as over 400m in height, and as the summit has now been surveyed with the Trimble GeoXH 6000, it is this result that is being prioritised for listing purposes. 

The Trimble GeoXH 6000 gathering data at the summit of Hergest Ridge (SO 246 557)

Therefore, the confirmation of the addition of this hill to Pedwar status under the National Top classification is due to LIDAR analysis and a subsequent Trimble GeoXH 6000 survey, resulting in a 401.0m summit height and a 269.4m bwlch height, with these values giving this hill 131.7m of drop which is sufficient for it to be classified as a Pedwar. 

 

The full details for the hill are:

Group:  Gwaun Ceste 

Name:  Hergest Ridge

OS 1:50,000 map:  148

Summit Height:  401.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 24693 55769 (Trimble GeoXH 6000)

Bwlch Height:  269.5m (LIDAR)

Bwlch Grid Reference:  SO 22053 55707 (LIDAR)

Drop:  131.5m (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Aled Williams and Myrddyn Phillips (October 2021) 

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Boncyn Nadroedd (SJ 027 540) – 390m Double Sub-Pedwar deletion (96th reclassification)

There has been a deletion to the listing of the Y Pedwarau – The 400m 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 deletion applies to are:

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being deleted from the 390m Double Sub-Pedwar category.  The criteria for this sub category being all Welsh hills at or above 390m and below 400m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Boncyn Nadroedd and it is adjoined to the Mynydd Hiraethog group of hills which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with minor roads to its north, west and east, and has the town of Rhuthun (Ruthin) towards the east north-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 that accompanied the main P30 list, as it was considered not to meet the criteria then used for this sub category.  

When 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 23m of drop, based on interpolated values of c 390m and c 367m for its summit and bwlch respectively, with each based on interpolation of 10m contouring on the Ordnance Survey 1:25,000 Explorer map, and these were the details that it appeared under after the 390m sub categories were added to the Y Pedwarau list.

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 has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the estimated bwlch height for this hill being amended to c 368m, with this based on interpolation of 5m contouring between 365m – 370m.

Extract from the Magic Maps website

The details for this hill were also re-assessed against Ordnance Survey data hosted on the Magic Maps website as well as the WalkLakes website, and what was thought to be a tiny uppermost 390m summit ring contour is given a 389m spot height on these two interactive maps, implying that what was taken as a small ring contour on the Ordnance Survey 1:25,000 Explorer map, is in fact a spot height missing its 389m height.

Extract from the WalkLakes website

Therefore, the deletion of this hill from 390m Double Sub-Pedwar status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 389m summit height and a c 368m bwlch height, with these values giving this hill c 21m of drop, which is insufficient for it to be classified as a 390m Double Sub-Pedwar.

The full details for the hill are:

Group:  Mynydd Hiraethog

Name:  Boncyn Nadroedd

OS 1:50,000 map:  116

Summit Height:  389m (spot height)

Summit Grid Reference:  SJ 02740 54035 (spot height)

Bwlch Height:  c 368m (interpolation)

Bwlch Grid Reference:  SJ 02565 54068 (interpolation)

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

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Aled Williams and Myrddyn Phillips (November 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Allt y Moch (SO 022 849) – 400m Sub-Pedwar reclassified to Pedwar (95th reclassification)

1st Survey post for Allt y Moch

2nd Survey post for Allt y Moch

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips and Aled Williams, which was prompted by detail produced by Joe Nuttall’s summit analysis programme and subsequent evaluation conducted by Ronnie Bowron. 

Allt y Moch (SO 022 849)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for this sub category being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Allt y Moch and it is adjoined to the Pegwn Mawr group of hills which are situated in Mid and West Wales (Region B, Sub-Region B1), and it is positioned with a minor dead end road to its south and the A470 road to its north-west, and has the village of Llandinam towards the north. 

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website this hill was included in the accompanying Hills to be surveyed sub list as it had been surveyed using a basic levelling staff by Myrddyn Phillips on the 18^th August 2003 as having 96½ft / 29.4m of drop. 

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

The evaluation by Ronnie Bowron of the detail produced by Joe Nuttall’s summit analysis programme prompted this hill’s details to be re-assessed via the mapping on the OS Maps website.  This is the replacement for OS Get-a-map and had contours at 5m intervals which were proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  The bwlch contours on this mapping were between 385m – 390m, therefore if the 421m summit spot height was accurate it meant this hill had at least 30m of drop and would qualify for Pedwar status.  Because of this it was prioritised for a Trimble GeoXH 6000 survey. 

Allt y Moch was surveyed over two days; 11^th July 2020 and 18^th October 2020, with seven data sets taken at the area of its bwlch and six data sets taken at the area of its summit, resulting in the hill now being listed with 30.1m of drop. 

The Trimble GeoXH 6000 gathering data at the bwlch of Allt y Moch

The Trimble GeoXH 6000 gathering data at the summit of Allt y Moch

Therefore, the reclassification of this hill from 400m Sub-Pedwar status is due to a Trimble GeoXH 6000 survey resulting in a 419.7m summit height and a 389.6m bwlch height, with these values giving this hill 30.1m of drop, which is sufficient for it to be classified as a Pedwar. 

 

The full details for the hill are:

Group:  Pegwn Mawr 

Name:  Allt y Moch 

OS 1:50,000 map:  136

Summit Height:  419.7m (converted to OSGM15) 

Summit Grid Reference:  SO 02202 84938 

Bwlch Height:  389.6m (converted to OSGM15) 

Bwlch Grid Reference:  SO 02366 84827 

Drop:  30.1m

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (October 2020)

  

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Catel (SN 697 506) – 400m Sub-Pedwar addition (94th reclassification)

There has been an addition to the listing of the Y Pedwarau – The 400m 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.

Bryn Catel (SN 697 506)

This was initiated by Joe Nuttall who produced a summit analysis programme that used LIDAR with an alternative height map (DEM) allowing identification of summits and bylchau and thereby drops.  The resulting spreadsheet that Joe produced contains over 29,600 hills.

This spreadsheet is being evaluated by a number of people, including Ronnie Bowron, who passed the details of this hill to us.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Bryn Catel, and it is adjoined to the Esgair Wen group of hills, which are situated in the central part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with minor roads to its north, west and south and farther afield it has the B4343 road to its west, and the village of Llanddewibrefi towards the north-west.

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website this hill was not included in the main P30 list or in the Hills to be surveyed sub list that accompanied it, as it was considered not to meet the criteria then used for either category. 

After the P30 lists were standardised, and interpolated heights and drop values also included, the hill was still not included, and neither was it when the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013; it had been completely missed.

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

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey 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 are current and digitally updated such as the mapping on the WalkLakes website, and it is this mapping that gives this hill a 426m summit spot height.

Extract from the WalkLakes website

The details for this hill were also re-assessed against 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.  This resulted in its bwlch height being listed as an estimated c 402m based on interpolation of 5m contouring between 400m – 405m.

Extract from the OS Maps website

Therefore, the confirmation of the addition of this hill to 400m Sub-Pedwar status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 426m summit height and a c 402m bwlch height, with these values giving this hill c 24m of drop which is sufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Esgair Wen

 

Name:  Bryn Catel

OS 1:50,000 map:  146

Summit Height:  426m (spot height)

Summit Grid Reference:  SN 69703 50643 (spot height)

Bwlch Height:  c 402m (interpolation)

Bwlch Grid Reference:  SN 69786 50962 (interpolation)

Drop:  c 24m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (October 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 464.2m (SO 133 488) – 400m Sub-Pedwar addition (93rd reclassification)

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Pt. 464.2m (SO 133 488)

This was initiated by Joe Nuttall who produced a summit analysis programme that used LIDAR with an alternative height map (DEM) allowing identification of summits and bylchau and thereby drops.  The resulting spreadsheet that Joe produced contains over 29,600 hills.

This spreadsheet is being evaluated by a number of people, including Ronnie Bowron, who passed the details of this hill to us.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

For now the hill is being listed by the point (Pt. 464.2m) notation, and it is adjoined to the Gwaun Ceste group of hills, which are situated in the eastern part of Mid and West Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its north-east, B4567 and A470 roads to its west and the B4594 road to its south, and has the village of Aberedw towards the west south-west.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was not included as it was listed with an estimated c 19m of drop, based on the 464m summit spot height and an estimated c 445m bwlch height, with the latter based on interpolation of 10m contouring between 440m – 450m that appear 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. 

LIDAR summit image of Pt. 464.2m (SO 133 488)

Therefore, the confirmation of the addition of this hill to 400m Sub-Pedwar status is due to LIDAR analysis, resulting in a 464.2m summit height and a 443.4m bwlch height, with these values giving this hill 20.8m of drop which is sufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Gwaun Ceste  

Name:  Pt. 464.2m

OS 1:50,000 map:  148

Summit Height:  464.2m (LIDAR)

Summit Grid Reference:  SO 13377 48863 (LIDAR)

Bwlch Height:  443.4m (LIDAR)

Bwlch Grid Reference:  SO 12937 48507 (LIDAR)

Drop:  20.8m (LIDAR)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (October 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Llwyd (SN 772 763) – 400m Sub-Pedwar addition (92nd reclassification)

There has been an addition to the listing of the Y Pedwarau – The 400m 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.

This was initiated by Joe Nuttall who produced a summit analysis programme that used LIDAR with an alternative height map (DEM) allowing identification of summits and bylchau and thereby drops.  The resulting spreadsheet that Joe produced contains over 29,600 hills.

This spreadsheet is being evaluated by a number of people, including Ronnie Bowron, who passed the details of this hill to us.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Bryn Llwyd, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with the A44 road to its north-east, the A4120 to its north-west and the B4574 road to its south, and has the village of Pontarfynach (Devil’s Bridge) towards the west.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was not included as it was listed with an estimated c 19m of drop, based on the 474m summit spot height and an estimated c 455m bwlch height, with the latter based on interpolation of 10m contouring that appears on the Ordnance Survey 1:25,000 Explorer map.

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

With the summit analysis programme produced by Joe Nuttall and the examination of its data by Ronnie Bowron, the details for this hill have now been re-assessed against mapping on the OS Maps website.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 453m bwlch height based on interpolation of 5m contouring between 450m – 455m, resulting in the drop value increasing to an estimated c 21m. 

Extract from the OS Maps website

Therefore, the addition of this hill to 400m Sub-Pedwar status is due to re-assessment of detail derived from contemporary maps produced from Ordnance Survey data, resulting in a 474m summit height and an estimated c 453m bwlch height, with these values giving this hill c 21m of drop which is sufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Bryn Llwyd

OS 1:50,000 map:  135, 147

Summit Height:  474m (spot height)

Summit Grid Reference:  SN 77211 76332 (spot height)

Bwlch Height:  c 453m (interpolation)

Bwlch Grid Reference:  SN 77520 76421 (interpolation)

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

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (September 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Llwyd (SO 108 825) – 400m Sub-Pedwar addition (91st reclassification)

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps.

This was initiated by Joe Nuttall who produced a summit analysis programme that used LIDAR with an alternative height map (DEM) allowing identification of summits and bylchau and thereby drops.  The resulting spreadsheet that Joe produced contains over 29,600 hills.

This spreadsheet is being evaluated by a number of people, including Ronnie Bowron, who passed the details of this hill to us.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Bryn Llwyd, and it is adjoined to the Beacon Hill group of hills, which are situated in the north-eastern part of Mid and West Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its south and east, and the A483 road to its west and farther afield the B4355 road to its north-east, and has the town of Y Drenewydd (Newtown) towards the north.

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

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was not included as it was listed with 19m of drop, based on the 485m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 466m spot height that appeared on a minor road on the area of this hill’s bwlch on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.  This latter spot height also appears on the Magic Map website.

Extract from the Magic Maps website

With the summit analysis programme produced by Joe Nuttall and the examination of its data by Ronnie Bowron, the details for this hill have now been re-assessed against mapping on the OS Maps website.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 465m bwlch height based on interpolation of 5m contouring between 460m – 465m, resulting in the drop value increasing to an estimated c 20m. 

Extract from the OS Maps website

Therefore, the addition of this hill to 400m Sub-Pedwar status is due to re-assessment of detail on contemporary Ordnance Survey maps, resulting in a 485m summit height and an estimated c 465m bwlch height, with these values giving this hill c 20m of drop which is sufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Beacon Hill

 

Name:  Bryn Llwyd

OS 1:50,000 map:  136

Summit Height:  485m (spot height)

Summit Grid Reference:  SO 10859 82548 (spot height)

Bwlch Height:  c 465 (interpolation)

Bwlch Grid Reference:  SO 11088 82983 (interpolation)

Drop:  c 20m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (September 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Lan Fawr (SN 692 501) – Pedwar reclassified to 400m Sub-Pedwar (90th reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted on the 5^th January 2020 by Myrddyn Phillips with assistance from Rob Woodall.

Lan Fawr (SN 692 501)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Lan Fawr, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with the Afon Teifi and the B4343 road to its north-west and the A482 road to its south-west, and has the village of Llanbedr Pont Steffan (Lampeter) towards the west.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with 28m of drop, based on a 429m summit height that appears as a spot height on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and a 401m bwlch height that appeared as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map and which is positioned at SN 69498 50464.  This spot height is also shown on Ordnance Survey data that appears on the Magic Maps website. 

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 has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 30m of drop, based on interpolation of 5m bwlch contouring between 395m – 400m.

The Trimble GeoXH 6000 gathering data at the summit of Lan Fawr

The 401m spot height that appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map originates from a 1316ft (401.1m) imperial height that appears on the Ordnance Survey series of Six-Inch maps.  This seems to be a levelled height and was not necessarily taken to the critical point of this bwlch.  As a consequence of these re-assessments this hill was reclassified to a Pedwar with an estimated c 30m of drop.

The Trimble GeoXH 6000 gathering data at the bwlch of Lan Fawr

Therefore, the reclassification of this hill from Pedwar back to 400m Sub-Pedwar status is due to a Trimble GeoXH 6000 survey, resulting in a 427.4m summit height and a 398.3m bwlch height, with these values giving this hill 29.1m of drop which is insufficient for it to be classified as a Pedwar.

The full details for the hill are:

Group:  Elenydd

Name:  Lan Fawr

OS 1:50,000 map:  146

Summit Height:  427.4m (Trimble GeoXH 6000)

Summit Grid Reference:  SN 69244 50156 (Trimble GeoXH 6000)

Bwlch Height:  398.3m (Trimble GeoXH 6000)

Bwlch Grid Reference:  SN 69493 50467 (Trimble GeoXH 6000)

Drop:  29.1m (Trimble GeoXH 6000 summit and bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (May 2020)






Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 413m (SO 105 018) – 400m Sub-Pedwar reclassified to Pedwar (89th reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps.

Pt. 413m (SO 105 018).  Photo image from Google Maps

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The hill is being listed by the point (Pt. 413m) notation as an appropriate name for it either through local enquiry and / or historic research has not been found by the authors, and it is adjoined to the Cymoedd Gwent group of hills, which are situated in the eastern part of South Wales (Region C, Sub-Region C2), and it is positioned with minor roads to its north, east and south, with the B4255 road to its south-west, the A4054 road and the A470 road further to its west and the A469 road further to its east, and has the town of Merthyr Tudful towards the north-west.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with an estimated c 29m drop, based on the 413m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 384m bwlch height based on interpolation of 10m contouring between 380m – 390m.

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 has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 31m of drop, based on interpolation of 5m bwlch contouring between 380m – 385m.

Extract from the OS Maps website

The details for this hill were also examined using the largest scale interactive map hosted on the Geograph website; this mapping shows a 414m spot height on the summit area of this hill and a 382m spot height on the narrow road just above where interpolation places the critical point of this hill’s bwlch.  These values have not been taken in the listed heights and drop for this hill, but are more evidence that it meets the required minimum 30m of drop to qualify for Pedwar status.

Summit extract from the interactive map hosted on the Geograph website

Bwlch extract from the interactive map hosted on the Geograph website

Therefore, the reclassification of this hill from 400m Sub-Pedwar to Pedwar status is due to re-assessment of detail on contemporary Ordnance Survey maps, resulting in a 413m summit height and an estimated c 382m bwlch height, with these values giving this hill c 31m of drop which is sufficient for it to be classified as a Pedwar.

The full details for the hill are:

Group:  Cymoedd Gwent

Name:  Pt. 413m

OS 1:50,000 map:  171

Summit Height:  413m (spot height)

Summit Grid Reference:  SO 10581 01800 (spot height)

Bwlch Height:  c 382m (interpolation)

Bwlch Grid Reference:  SO 11053 01910 (interpolation)

Drop:  c 31m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (May 2020)






Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 402.3m (SN 964 370) – 400m Sub-Pedwar deletion (88th reclassification)

There has been a deletion to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Aled Williams.

LIDAR image of Pt. 402.3m (SN 964 370)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being deleted from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The hill is being listed by the point (Pt. 402.3m) notation as an appropriate name for it either through local enquiry and / or historic research has not been found by the authors, and it is adjoined to the Mynydd Epynt group of hills, which are situated in the south-eastern part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with the A40 road to its south and the B4520 road to its east, and has the hamlet of Merthyr Cynog towards the east.

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

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with 20m of drop, based on the 403m summit height that appears as a spot height on the Ordnance Survey 1:25,000 Explorer map and the 383m bwlch height that appeared as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage map.  The 383m bwlch spot height is also shown on Ordnance Survey data that appears on the Magic Maps website. 

Extract from the Magic Maps website

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 has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment enabled the position of the 383m bwlch spot height to be compared to the positioning of the 5m bwlch contouring, resulting in the drop value for this hill provisionally decreasing to an estimated c 16m based on an estimated bwlch height of c 387m.

Extract from OS 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.

Therefore, the deletion of this hill from 400m Sub-Pedwar status is due to LIDAR analysis, resulting in a 402.3m summit height and a 385.4m bwlch height, with these values giving this hill 16.8m of drop, which is insufficient for 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Mynydd Epynt 

Name:  Pt. 402.3m

OS 1:50,000 map:  160

Summit Height:  402.3m (LIDAR)

Summit Grid Reference:  SN 96417 37069 (LIDAR)

Bwlch Height:  385.4m (LIDAR)

Bwlch Grid Reference:  SN 95979 37133 (LIDAR)

Drop:  16.8m (LIDAR)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Aled Williams and Myrddyn Phillips (March 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Cyrnau (SN 735 536) – 400m Sub-Pedwar deletion (87th reclassification)

There has been a deletion to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being deleted from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Cyrnau, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with a minor road to its north-west and south, and has the town of Tregaron towards the north-west.

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

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with an estimated c 20m of drop, based on the 446m summit height that appeared as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage map and an estimated c 426m bwlch height based on interpolation of 10m contouring between 420m – 430m on the Ordnance Survey 1:25,000 Explorer map.  The 446m summit spot height is also shown on Ordnance Survey data that appears on the Magic Maps website. 

Extract from the Magic Maps website

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 has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 427m bwlch height based on interpolation of 5m contouring between 425m – 430m, resulting in the drop value decreasing to an estimated c 19m. 

Extract from the OS Maps website

Therefore, the deletion of this hill from 400m Sub-Pedwar status is due to re-assessment of detail on contemporary Ordnance Survey maps, resulting in a 446m summit height and an estimated c 427m bwlch height, with these values giving this hill c 19m of drop which is insufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Cyrnau

OS 1:50,000 map:  146, 147

Summit Height:  446m (spot height)

Summit Grid Reference:  SN 73549 53650 (spot height)

Bwlch Height:  c 427 (interpolation)

Bwlch Grid Reference:  SN 73606 53426 (interpolation)

Drop:  c 19m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (March 2020)






Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Dilyw (SN 835 779) – 400m Sub-Pedwar deletion (86th reclassification)

There has been a deletion to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps and aerial maps.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being deleted from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Bryn Dilyw, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with the A44 road to its north and the A470 road to its east, and has the village of Llangurig towards the east north-east.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with an estimated c 21m of drop, based on a 480m summit height that appears as a spot height on the Ordnance Survey 1:50,000 Landranger map and a small uppermost contour that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 459m bwlch height based on interpolation of 10m contouring between 450m – 460m 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 has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 461m bwlch height based on interpolation of 5m contouring between 460m – 465m.

Extract from the OS Maps website

This hill is immersed in a conifer plantation which also hosts wind turbines, and examination of aerial maps has concluded that the land where the small 480m ring contour appears is likely to be man-made as it resembles a deposit of earth from the construction of a turning point near to one of the turbines, therefore the summit height and position now used for this hill is given to the 478m spot height that appears on Ordnance Survey 1:25,000 Explorer maps.  When coupled with this hill’s estimated c 461m bwlch height, these values give this hill c 17m of drop.

Therefore, the deletion of this hill from 400m Sub-Pedwar status is due to re-assessment of detail on contemporary Ordnance Survey maps and the use of aerial maps, resulting in a 478m summit height and an estimated c 461m bwlch height, with these values giving this hill c 17m of drop which is insufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Bryn Dilyw

OS 1:50,000 map:  135, 136, 147

Summit Height:  478m (spot height)

Summit Grid Reference:  SN 83554 77970 (spot height)

Bwlch Height:  c 461 (interpolation)

Bwlch Grid Reference:  SN 83227 78076 (interpolation)

Drop:  c 17m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (March 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau


THIS HILL HAS SUBSEQUENTLY BEEN RECLASSIFIED BACK TO SUB-PEDWAR STATUS

Lan Fawr (SN 692 501) – 400m Sub-Pedwar reclassified to Pedwar (85th reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps.

Lan Fawr (SN 692 501)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Lan Fawr, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with the Afon Teifi and the B4343 road to its north-west and the A482 road to its south-west, and has the village of Llanbedr Pont Steffan (Lampeter) towards the west.

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

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with 28m of drop, based on a 429m summit height that appears as a spot height on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and a 401m bwlch height that appeared as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map and which is positioned at SN 69498 50464.  This spot height is also shown on Ordnance Survey data that appears on the Magic Maps website. 

Extract from the Magic Maps website

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 has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 30m of drop, based on interpolation of 5m bwlch contouring between 395m – 400m.

Extract from the OS Maps website

The 401m spot height that appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map originates from a 1316ft (401.1m) imperial height that appears on the Ordnance Survey series of Six-Inch maps.  This seems to be a levelled height and was not necessarily taken to the critical point of this bwlch.

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the reclassification of this hill from 400m Sub-Pedwar to Pedwar status is due to re-assessment of detail on contemporary Ordnance Survey maps, resulting in a 429m summit height and an estimated c 399m bwlch height, with these values giving this hill c 30m of drop which is sufficient for it to be classified as a Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Lan Fawr

OS 1:50,000 map:  146

Summit Height:  429m (spot height)

Summit Grid Reference:  SN 69253 50157 (spot height)

Bwlch Height:  c 399m (interpolation)

Bwlch Grid Reference:  SN 69480 50453 (interpolation)

Drop:  c 30m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (March 2020)






Mapping Mountains - Hill Reclassifications - Y Pedwarau

Cerrig Llwydion (SN 909 731) – 500m Sub-Pedwar addition (84th reclassification)

Summit Relocations post for Cerrig Llwydion

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Aled Williams.

LIDAR image of Cerrig Llwydion (SN 909 731)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 500m Sub-Pedwar category.  The criteria for 500m Sub-Pedwar status being all Welsh hills at or above 500m and below 510m in height that have 30m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Cerrig Llwydion and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and is positioned with the Afon Gwy (River Wye) and the A470 road to its north-east, and has the village of Llangurig towards the north.

When the original 400m 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 that accompanied the main P30 list, as only 400m sub hills were then a part of this list.

When the 390m subs and latterly the 500m subs were added to this list this hill was not included, as it was listed with a c 510m summit height based on an estimation of its height in comparison to the 508m map heighted summit of Sychnentydd (SN 910 724).

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

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps. 

  

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill remaining listed with an estimated c 510m summit height.

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 Cerrig Llwydion and Sychnentydd

Therefore, the addition of this hill to 500m Sub-Pedwar status is due to LIDAR summit analysis, resulting in a 509.4m summit height and when coupled with the 462.0m bwlch height, these values give this hill 47.4m of drop which is sufficient for it to be classified as a 500m Sub-Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Cerrig Llwydion

OS 1:50,000 map:  136, 147

Summit Height:  509.4m (LIDAR)

Summit Grid Reference:  SN 90965 73141 (LIDAR)

Bwlch Height:  462.0m (LIDAR)

Bwlch Grid Reference:  SN 92807 72279 (LIDAR)

Drop:  47.4m (LIDAR)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (February 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 509.6m (SN 815 686) – 500m Double Sub-Pedwar addition (83rd reclassification)

There has been an addition to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height and its location confirmed by LIDAR analysis conducted by Aled Williams, and the bwlch height, its location, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps.

LIDAR image of Pt. 509.6m (SN 815 686)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 500m Double Sub-Pedwar category.  The criteria for 500m Double Sub-Pedwar status being all Welsh hills at or above 500m and below 510m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The hill is being listed by the point (Pt. 509.6m) notation, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and is positioned with Llyn Teifi to its west south-west and the Claerwen Reservoir to its south-east, and has the village of Pontrhydfendigaid towards the west south-west.

When the original 400m 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 that accompanied the main P30 list, as only 400m sub hills were then a part of this list.

When the 390m subs and latterly the 500m subs were added to this list this hill was not included, as it was listed with a 510m summit height based on the spot height 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

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps. 

   

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill remaining listed with a 510m summit height and an estimated drop of c 21m.

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 Pt. 509.6m (SN 815 686)

Therefore, the addition of this hill to 500m Double Sub-Pedwar status is due to LIDAR summit analysis, resulting in a 509.6m summit height and when coupled with the estimated c 489m bwlch height, these values give this hill c 21m of drop which is sufficient for it to be classified as a 500m Double Sub-Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Pt. 509.6m

OS 1:50,000 map:  135, 136, 147

Summit Height:  509.6m (LIDAR)

Summit Grid Reference:  SN 81513 68623 (LIDAR)

Bwlch Height:  c 489m (interpolation)

Bwlch Grid Reference:  SN 81259 68985 (interpolation)

Drop:  c 21m (LIDAR summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (February 2020)






Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 427m (SN 731 497) – Pedwar reclassified to 400m Sub-Pedwar (82nd reclassification)

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified to 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The hill is being listed by the point (Pt. 427m) notation as an appropriate name for it either through local enquiry and / or historic research has not been found by the authors, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and is positioned with minor roads to its north, west, south and east, and has the village of Llanddewi Brefi towards the north-west.

When the original 400m 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 that accompanied the main P30 list, as it was considered not to meet the criteria then used for the main P30 list. 

When 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 30m of drop, based on the 427m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 397m based on interpolation of 10m contouring between 390m – 400m, and the above details were used when the hill was listed in the 1^st edition of the Y Pedwarau published by Europeaklist in May 2013.

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

Since publication of the 1^st edition of Y Pedwarau there are Ordnance Survey maps that are now also available online.  The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps; however the details for this hill remained the same as no additional spot heights appear on this map.

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This latest re-assessment resulted in the hill being listed with an estimated c 29m of drop, based on interpolation of 5m bwlch contouring between 395m – 400m.

Extract from the OS Maps website

Another resource now available online is the WalkLakes website which hosts an interactive Ordnance Survey map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available Ordnance Survey maps and for this hill’s summit the 427m spot height also appears in the same position as it does on the Ordnance Survey 1:25,000 Explorer map, however the bwlch contours are between 400m – 410m which if taken would give this hill a lower value that the estimated c 29m of drop.

Extract from the WalkLakes website

Therefore, the reclassification of this hill from Pedwar to 400m Sub-Pedwar status is due to re-assessment of detail on contemporary Ordnance Survey maps, resulting in a 427m summit height and an estimated c 398m bwlch height, with these values giving this hill c 29m of drop which is insufficient for continued classification as a Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Pt. 427m

OS 1:50,000 map:  146, 147

Summit Height:  427m (spot height)

Summit Grid Reference:  SN 73157 49745 (hand-help GPS via DoBIH)

Bwlch Height:  c 398m (interpolation)

Bwlch Grid Reference:  SN 72735 49830 (interpolation)

Drop:  c 29m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (February 2020)






Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Twyn (SH 815 241) – 400m Sub-Pedwar addition (81st reclassification)

There has been an addition to the listing of Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Bryn Twyn (SH 815 241)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Bryn Twyn, and it is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with the A494 road to its south-east, and has the small community of Rhyd-y-main towards the south-west.

Prior to LIDAR analysis this hill was originally listed with an estimated c 16m of drop, based on an estimated c 443m summit height and an estimated c 427m bwlch height, with these heights derived from interpolation of 10m contouring on the Ordnance Survey 1:50,000 Landranger and 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 Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping has many spot heights not on other publicly available Ordnance Survey maps.

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  These re-assessments resulted in the hill being listed with an estimated c 19m of drop, with the altered drop value based on interpolation taken from the uppermost 445m summit contour on OS Maps.

Extract from OS 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. 

Therefore, the addition of Bryn Twyn to 400m Sub-Pedwar status is due to LIDAR analysis, resulting in a 447.1m summit height and a 426.3m bwlch height, with these values giving this hill 20.8m of drop which is sufficient for it to be classified as a 400m Sub-Pedwar.

The full details for the hill are:

Group:  Arenig

Name:  Bryn Twyn

OS 1:50,000 map:  124, 125

Summit Height:  447.1m (LIDAR)

Summit Grid Reference:  SH 81545 24141 (LIDAR)

Bwlch Height:  426.3m (LIDAR)

Bwlch Grid Reference:  SH 81619 24316 (LIDAR)

Drop:  20.8m (LIDAR)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (January 2020)






Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 437m (SH 751 407) – 400m Sub-Pedwar addition (80th reclassification)

There has been an addition to the listing of Y Pedwarau due to analysis of data on the Geograph and WalkLakes websites, coupled with the 5m contouring on the OS Maps website.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

As the authors do not know a name for this hill either from local enquiry and / or historic research it is being listed by the point (Pt. 437m) notation, and it is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with the B4391 road to its north, the A470 road to its west and the A4212 road to its south, and has the village of Ffestiniog towards the west north-west.

Prior to analysis of data on the Geograph and WalkLakes websites this hill was not classified as contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps give it an uppermost 430m ring contour and bwlch contouring between 420m – 430m, implying it does not have sufficient drop for 400m Sub-Pedwar status.

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

The details for this hill were re-assessed when the Ordnance Survey non-contour Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping has many spot heights not on other publicly available Ordnance Survey maps and importantly for this hill it has a 437m summit spot height positioned at SH 75146 40791.   

Extract from the Ordnance Survey non-contour Vector Map Local hosted on the Geograph website

Another resource now available online is the WalkLakes website which hosts an interactive Ordnance Survey map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available Ordnance Survey maps and for this hill’s summit the 437m spot height also appears in the same position as it does on the non-contour Vector Map Local hosted on the Geograph website.

Extract from the WalkLakes website

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  These re-assessments resulted in the hill being listed with an estimated c 20m of drop.

Extract from the OS Maps website

Therefore, the addition of Pt. 437m to 400m Sub-Pedwar status is due to the analysis of data on the Geograph and WalkLakes websites with the estimated bwlch height derived from 5m contouring on the OS Maps website.  Resulting in this hill being listed with a 437m summit height that appears as a spot height on the non-contour Vector Map Local hosted on the Geograph website and on the WalkLakes website and an estimated bwlch height of c 417m based on 5m contouring between 415m – 420m on the OS Maps website, with these values giving this hill an estimated c 20m of drop, which is sufficient for 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Arenig 

Name:  Pt. 437m

OS 1:50,000 map:  124

Summit Height:  437m (spot height)

Summit Grid Reference:  SH 75146 40791 (spot height)

Bwlch Height:  c 417m (interpolation)

Bwlch Grid Reference:  SH 75126 40688 (interpolation)

Drop:  c 20m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (January 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Pt. 447m (SH 741 408) – 400m Sub-Pedwar addition (79th reclassification)

There has been an addition to the listing of Y Pedwarau due to analysis of data on the Geograph and WalkLakes websites, coupled with the 5m contouring on the OS Maps website.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

As the authors do not know a name for this hill either from local enquiry and / or historic research it is being listed by the point (Pt. 447m) notation, and it is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with the Afon Cynfal and the B4391 road to its north-west and the A470 road to its west, and has the village of Ffestiniog towards the west north-west.

Prior to analysis of data on the Geograph and WalkLakes websites this hill was listed with an estimated c 14m of drop based on an estimated c 442m summit height and an estimated c 428m bwlch height, with these interpolations taken from 10m contours on the contemporary 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 Ordnance Survey non-contour Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping has many spot heights not on other publicly available Ordnance Survey maps and importantly for this hill it has a 447m summit spot height positioned at SH 74113 40832.    

Extract from the Ordnance Survey non-contour Vector Map Local hosted on the Geograph website

Another resource now available online is the WalkLakes website which hosts an interactive Ordnance Survey map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available Ordnance Survey maps and for this hill’s summit the 447m spot height also appears in the same position as it does on the non-contour Vector Map Local hosted on the Geograph website.

Extract from the WalkLakes website

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  These re-assessments resulted in the hill being listed with an estimated c 20m of drop.

Extract from the OS Maps website

Therefore, the addition of Pt. 447m to 400m Sub-Pedwar status is due to the analysis of data on the Geograph and WalkLakes websites with the estimated bwlch height derived from the 5m contouring on the OS Maps website.  Resulting in this hill being listed with a 447m summit height that appears as a spot height on the non-contour Vector Map Local hosted on the Geograph website and on the WalkLakes website and an estimated bwlch height of c 427m based on 5m contouring between 425m – 430m on the OS Maps website, with these values giving this hill an estimated c 20m of drop, which is sufficient for 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Arenig

Name:  Pt. 447m

OS 1:50,000 map:  124

Summit Height:  447m (spot height)

Summit Grid Reference:  SH 74113 40832 (spot height)

Bwlch Height:  c 427m (interpolation)

Bwlch Grid Reference:  SH 74233 40554 (interpolation)

Drop:  c 20m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (January 2020)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Crwn (SH 785 456) – 400m Sub-Pedwar addition (78th reclassification)

There has been an addition to the listing of Y Pedwarau - The 400m Hills of Wales due to analysis of data on the Geograph and WalkLakes websites, coupled with the 5m contouring on the OS Maps website.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Bryn Crwn, and it is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with a minor road to its west and the B4407 road to its south and has Llyn Conwy to its north-west, and has the village of Penmachno towards the north and Ysbyty Ifan towards the north-east.

Prior to analysis of data on the Geograph and WalkLakes websites this hill was listed with an estimated c 19m of drop based on the 487m summit spot height that appears on contemporary Ordnance Survey 1:25,000 Explorer maps and an estimated bwlch height of c 468m based on interpolation of 10m contouring between 460m – 470m.

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

The details for this hill were re-assessed when the Ordnance Survey non-contour Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping has many spot heights not on other publicly available Ordnance Survey maps and importantly for this hill it has a 488m summit spot height positioned over 130 metres from where the 487m spot height appears on the Ordnance Survey 1:25,000 Explorer map indicating a higher position within the uppermost contour.

Another resource now available online is the WalkLakes website which hosts an interactive Ordnance Survey map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available Ordnance Survey maps and for this hill’s summit the 488m spot height also appears in the same position as it does on the non-contour Vector Map Local hosted on the Geograph website.

Extract from the WalkLakes website

The details for this hill were also re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  These re-assessments resulted in the hill being listed with an estimated c 20m of drop.

Extract from the OS Maps website

Therefore, the addition of Bryn Crwn to 400m Sub-Pedwar status is due to the analysis of data on the Geograph and WalkLakes websites with the estimated bwlch height confirmed via the 5m contouring on the OS Maps website.  Resulting in this hill being listed with a 488m summit height that appeared as a spot height on the Vector Map Local hosted on the Geograph website and appears as a spot height on the WalkLakes website and an estimated bwlch height of c 468m based on 5m contouring between 465m – 470m on the OS Maps website, with these values giving this hill an estimated c 20m of drop, which is sufficient for 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Arenig

Name:  Bryn Crwn

OS 1:50,000 map:  115

Summit Height:  488m (spot height)

Summit Grid Reference:  SH 78585 45680 (spot height)

Bwlch Height:  c 468m (interpolation)

Bwlch Grid Reference:  SH 78573 46134 (interpolation)

Drop:  c 20m

For the additions, reclassifications and deletions to Y Pedwarau - The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (December 2019)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Clogau (SJ 184 462) – 400m Sub-Pedwar addition (77th reclassification)

Significant Name Changes post for Clogau

There has been an addition to the listing of Y Pedwarau due to analysis of data on the OS Maps website, which is the recent replacement for OS Get-a-map.

Clogau (SJ 184 462)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being added to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Clogau, 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 with the A542 road to its north-east, the A5104 road to its north-west and the A5 road to its south, and has the town of Llangollen towards the south-east.

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

Prior to analysis of data on OS Maps this hill was listed with 17m of drop based on the 455m summit spot height that appears on contemporary Ordnance Survey 1:25,000 Explorer maps and a bwlch height of 438m that appears as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.

Extract from the OS Maps website

The addition of Clogau to 400m Sub-Pedwar status is due to the analysis of data on the OS Maps website.  This hill is now listed with an estimated c 460m summit height based on a 460m uppermost contour ring and an estimated bwlch height of c 439m based on bwlch contouring between 435m – 440m, with these values giving this hill c 21m of drop which is sufficient for 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Moel y Gamelin 

Name:  Clogau

OS 1:50,000 map:  116

Summit Height:  c 460m (interpolation)

Summit Grid Reference:  SJ 18455 46229 (interpolation)

Bwlch Height:  c 439m (interpolation)

Bwlch Grid Reference:  SJ 18304 46343 (interpolation)

Drop:  c 21m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (December 2019)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Y Foel (SJ 012 016) – 400m Sub-Pedwar deletion (76th reclassification)

There has been a deletion to the listing of Y Pedwarau - The 400m Hills of Wales due to analysis of data on the Ordnance Survey Vector Map Local, the OS Maps website and the WalkLakes website.

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height with 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being deleted from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name of the hill is Y Foel, and it is adjoined to the Carnedd Wen group of hills, which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is encircled by minor roads with the A458 further to its north and the A470 further to its south-west, and has the village of Carno towards the south-west.

Prior to the reassessment of this hill’s details it was listed with c 20m of drop based on the 414m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 394m based on bwlch contouring between 390m – 395m that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.

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

Since publication of the 1^st edition of Y Pedwarau by Europeaklist in May 2013 there have been a number of Ordnance Survey maps made available online, one of which is housed on the OS Maps website.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and the online Vector Map Local.

Extract from the OS Maps website

Another resource now available online is the WalkLakes website which houses an interactive Ordnance Survey map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on any other publicly available Ordnance Survey map and importantly for this hill shows a quarried area to the north of the summit as a depression and not an elevation.  These re-assessments resulted in the hill being listed with an estimated c 18m of drop.

Extract from the WalkLakes website

Therefore, the deletion of Y Foel from 400m Sub-Pedwar status is due to a combination of Ordnance Survey maps, including the Vector Map Local, the OS Maps website and the WalkLakes website, resulting in the hill now being listed with a 415m summit height that appears as a spot height on the Ordnance Survey non-contour Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map and on the WalkLakes website, and an estimated bwlch height of c 397m based on 5m contouring between 395m – 400m on the OS Maps website, with these values giving this hill an estimated c 18m of drop which is insufficient for continued 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Carnedd Wen

Name:  Y Foel

OS 1:50,000 map:  136

Summit Height:  415m (Vector Map Local and WalkLakes website)

Summit Grid Reference:  SJ 01221 01629 (spot height)

Bwlch Height:  c 397m (interpolation)

Bwlch Grid Reference:  SJ 01333 01839 (interpolation)

Drop:  c 18m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (November 2019)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Y Gribin (SH 906 175) – 400m Sub-Pedwar reclassified to Pedwar (75th reclassification)

There has been a reclassification to the listing of Y Pedwarau due to LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips, coupled with analysis of contemporary Ordnance Survey maps, including the 5m contouring on the OS Maps website, and Ordnance Survey data on the WalkLakes website.

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

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height with 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name of the hill is Y Gribin, and it is adjoined to the Y Berwyn group of hills, which are situated in the eastern part of North Wales (Region A, Sub-Region A4), and it is positioned with a minor road and the Afon Dyfi (River Dovey) to its west, and has the small community of Llanymawddwy towards the north.

This and its adjoining hill towards the south (which is also listed by the same name of Y Gribin) are both given a 485m summit spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and prior to this reclassification it was the southerly of these two hills (SH 902 172) that was prioritised for Pedwar status, whilst the northerly hill (SH 906 175) was listed as the 400m Sub-Pedwar.

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. 

The summit height produced by LIDAR analysis for the southerly of these two hills is 484.8m and is positioned at SH 90233 17288; however there is no LIDAR coverage for the northerly summit or the bylchau adjoined to each hill.

LIDAR summit image of the southerly of the two Y Gribin hills (SH 902 172)

The details for these two hills were then re-examined with contouring on the OS Maps website, this is the replacement for OS Get-a-map and has contours at 5m intervals.  The details for each hill were also examined via Ordnance Survey data on the WalkLakes website.  Lastly online logs that appear on the Hill Bagging website were consulted.  The data for each summit is given below:

Y Gribin

Ordnance Survey spot height:  485m (SH 902 172)

LIDAR: 484.8m summit at SH 90233 17288

OS Maps:  480m uppermost contour

WalkLakes spot height:  484m

Y Gribin

Ordnance Survey spot height:  485m (SH 906 175)

LIDAR:  not covered

OS Maps:  485m uppermost contour

WalkLakes website:  480m uppermost contour

There are two online logs of note on the Hill Bagging website, these have been posted by Anton Ciritus and Mick Moore and both make reference that in their view the northerly of these two summits is the higher.

Extract from the OS Maps website

Therefore, as evidence supports the northerly of the two Y Gribin summits to be the higher, this hill is reclassified from the 400m Sub-Pedwar to the Pedwar.

The reclassification of Y Gribin (SH 906 175) from 400m Sub-Pedwar to Pedwar status is due to a combination of factors, including LIDAR analysis, analysis of data on the OS Maps website and the WalkLakes website and online logs on the Hill Bagging website.  Therefore, with a 485m summit height that appears as a spot height on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and a 427m bwlch height that appears as a spot height on the Ordnance Survey 1:25,000 Explorer map, these values give this hill 58m of drop, which qualifies it for Pedwar status.

The full details for the hill are:

Group:  Y Berwyn 

Name:  Y Gribin

OS 1:50,000 map:  125

Summit Height:  485m (spot height)

Summit Grid Reference:  SH 90626 17580 (hand-held GPS via DoBIH)

Bwlch Height:  427m (spot height)

Bwlch Grid Reference:  SH 91702 17833 (spot height)

Drop:  58m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (October 2019)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Y Gribin (SH 902 172) – Pedwar reclassified to 400m Sub-Pedwar (74th reclassification)

There has been a reclassification to the listing of Y Pedwarau due to LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips, coupled with analysis of contemporary Ordnance Survey maps, including the 5m contouring on the OS Maps website, and Ordnance Survey data on the WalkLakes website.

LIDAR image of Y Gribin (SH 902 172)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height with 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name of the hill is Y Gribin, and it is adjoined to the Y Berwyn group of hills, which are situated in the eastern part of North Wales (Region A, Sub-Region A4), and it is positioned with a minor road and the Afon Dyfi (River Dovey) to its west, and has the small community of Llanymawddwy towards the north.

This and its adjoining hill towards the north (which is also listed by the same name of Y Gribin) are both given a 485m summit spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and prior to this reclassification it was the southerly of these two hills (SH 902 172) that was prioritised for Pedwar status, whilst the northerly hill (SH 906 175) was listed as the 400m Sub-Pedwar.

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. 

The summit height produced by LIDAR analysis for the southerly of these two hills is 484.8m and is positioned at SH 90233 17288; however there is no LIDAR coverage for the northerly summit or the bylchau adjoined to each hill.

LIDAR summit image of Y Gribin (SH 902 172)

The details for these two hills were then re-examined with contouring on the OS Maps website, this is the replacement for OS Get-a-map and has contours at 5m intervals.  The details for each hill were also examined via Ordnance Survey data on the WalkLakes website.  Lastly online logs that appear on the Hill Bagging website were consulted.  The data for each summit is given below:

Y Gribin

Ordnance Survey spot height:  485m (SH 902 172)

LIDAR: 484.8m summit at SH 90233 17288

OS Maps:  480m uppermost contour

WalkLakes spot height:  484m

Y Gribin

Ordnance Survey spot height:  485m (SH 906 175)

LIDAR:  not covered

OS Maps:  485m uppermost contour

WalkLakes website:  480m uppermost contour

There are two online logs of note on the Hill Bagging website, these have been posted by Anton Ciritus and Mick Moore and both make reference that in their view the northerly of these two summits is the higher.

Extract from the OS Maps website

Therefore, as evidence supports the northerly of the two Y Gribin summits to be the higher, the southerly summit is reclassified from the Pedwar to the 400m Sub-Pedwar.

Extract from the WalkLakes website

The reclassification of Y Gribin (SH 902 172) from Pedwar to 400m Sub-Pedwar status is due to a combination of factors, including LIDAR analysis, analysis of data on the OS Maps website and the WalkLakes website and online logs on the Hill Bagging website.  Therefore, with a 484.8m summit height ascertained from LIDAR analysis and an estimated bwlch height of c 462m taken from interpolation of 5m contouring on the OS Maps website, these values give this hill c 23m of drop, which qualifies it for 400m Sub-Pedwar status.

The full details for the hill are:

Group:  Y Berwyn

Name:  Y Gribin

OS 1:50,000 map:  125

Summit Height:  484.8m (LIDAR)

Summit Grid Reference:  SH 90233 17288 (LIDAR)

Bwlch Height:  c 462m (interpolation)

Bwlch Grid Reference:  SH 90496 17361 (interpolation)

Drop:  c 23m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (October 2019)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Moel yr Acre (SJ 169 526) – 400m Sub-Pedwar deletion (73rd reclassification)

There has been a deletion to the listing of Y Pedwarau due to analysis of data on the OS Maps website, which is the recent replacement for OS Get-a-map.

Moel yr Acre (SJ 169 526)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height with 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being deleted from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh 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 is published on Mapping Mountains in Google Doc format.

The name of the hill is Moel yr Acre, and it is adjoined to the Bryniau Clwyd group of hills, which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A525 road to its south, the B5429 road to its north-west and the B5431 road its north-east, and has the town of Rhuthun (Ruthin) towards the north-west.

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

Prior to analysis of data on OS Maps this hill was listed with c 20m of drop based on the 411.3m summit height ascertained from a Leica GS15 survey conducted by John Barnard and Myrddyn Phillips and an estimated bwlch height of c 391m based on interpolation of bwlch contouring between 390m – 395m on the Ordnance Survey 1:25,000 Explorer map.

Extract from the OS Maps website

The deletion of Moel yr Acre from 400m Sub-Pedwar status is due to the analysis of data on the OS Maps website and a re-assessment of bwlch contouring on the Ordnance Survey 1:25,000 Explorer map.  Therefore with a 411.3m summit height from the Leica GS15 survey and an estimated bwlch height of c 392m, based on bwlch contouring on OS Maps between 390m – 395m, this hill is now listed with c 19m of drop, which is insufficient for it to be classified as a 400m Sub-Pedwar. 

The full details for the hill are:

Group:  Bryniau Clwyd

Name:  Moel yr Acre

OS 1:50,000 map:  116

Summit Height:  411.3m (converted to OSGM15)

Summit Grid Reference:  SJ 16955 52668

Bwlch Height:  c 392m

Bwlch Grid Reference:  SJ 16994 53034 (interpolation)

Drop:  c 19m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (October 2019)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Bryn Hafod y Llan (SH 945 531) – 390m Double Sub-Pedwar addition (72nd reclassification)

There has been an addition of a hill to the list of the Y Pedwarau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips.

LIDAR image of Bryn Hafod y Llan (SH 945 531)

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

Y Pedwarau – Welsh hills at or above 400m and below 500m in height with 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being included in the 390m Double Sub-Pedwar category.  The criteria for 390m Double Sub-Pedwar status being all Welsh hills at or above 390m and below 400m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The name of the hill is Bryn Hafod y Llan, and it is adjoined to the Mynydd Hiraethog group of hills, which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A5 road to its south and the B4501 road to its east, and has the Alwen Reservoir to the north-east and the village of Cerrigydrudion towards the south. 

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 that accompanied the main P30 list, as it did not meet the criteria then used for this sub category. 

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 listed with an estimated c 18m of drop, based on an estimated summit height of c 397m and a bwlch height of 379m that appears as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.

Extract from the Ordnance Survey Vector Map Local hosted on the Geograph 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. 

The addition of Bryn Hafod y Llan to 390m Double Sub-Pedwar status is due to LIDAR analysis, resulting in a 398.7m summit height and a 378.5m bwlch height, with these values giving this hill 20.1m of drop which is sufficient for it to be classified as a 390m Double Sub-Pedwar.

The full details for the hill are:

Group:  Mynydd Hiraethog

Name:  Bryn Hafod y Llan

OS 1:50,000 map:  116

Summit Height:  398.7m (LIDAR)

Summit Grid Reference:  SH 94590 53115 (LIDAR)

Bwlch Height:  378.5m (LIDAR)

Bwlch Grid Reference:  SH 94564 52682 (LIDAR)

Drop:  20.1m (LIDAR)

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the available and following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (September 2019)

Mapping Mountains - Hill Reclassifications - Y Pedwarau

Cefn Cyfarwydd (SH 752 630) – 500m Double Sub-Pedwar reclassified to 500m Sub-Pedwar (71st reclassification)

Survey post for Cefn Cyfarwydd

There has been a reclassification of a hill that is listed in the Y Pedwarau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by a survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips and Aled Williams which took place on the 17^th February 2019.

Cefn Cyfarwydd (SH 752 630)

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

Y Pedwarau – Welsh hills at or above 400m and below 500m in height with 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from a 500m Double Sub-Pedwar to a 500m Sub-Pedwar.  The criteria for 500m Double Sub-Pedwar status being all Welsh hills at or above 500m and at or below 510m in height that have 20m or more and below 30m of drop, with the criteria for 500m Sub-Pedwar status being all Welsh hills at or above 500m and at or below 510m in height with 30m minimum drop.  The list is a joint compilation between Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The name of the hill is Cefn Cyfarwydd, and it is adjoined to the Carneddau 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 A5 road to its south and the B5106 and the A470 roads and the Afon Conwy to its east, and has the villages of Trefriw and Llanrwst towards the east.  

Prior to the survey with the Trimble GeoXH 6000 this hill was listed with 26m of drop based on the 503m summit and 477m bwlch spot heights that appear 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 Ordnance Survey Vector Map Local hosted on the Geograph website became available online; this mapping is entitled the Interactive Coverage Map.  As this mapping is larger in format it enables a better judgement of interpolated heights and it occasionally has contours at 5m intervals compared to the 10m contour intervals normally shown on the 1:25,000 Explorer map.  However, this mapping has the same spot heights and 10m contouring as the 1:25,000 Explorer map and therefore the drop value for this hill remained listed as 26m.

The area taking in this hill was re-examined when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals.  This mapping shows the 477m bwlch spot height to be positioned on a separate 475m contour ring implying that the height of this hill’s bwlch is substantially lower than 477m, with interpolation based on this contouring giving the hill c 30m of drop.  But it was not until the survey with the Trimble GeoXH 6000 that the increased drop value was confirmed.

Extract from the OS Maps website

The reclassification of Cefn Cyfarwydd from 500m Double Sub-Pedwar status is due to a survey with the Trimble GeoXH 6000, resulting in a 501.7m summit height and a 471.0m bwlch height, with these values giving this hill 30.7m of drop which is sufficient for it to be classified as a 500m Sub-Pedwar.

The Trimble GeoXH 6000 gathering data at the summit of Cefn Cyfarwydd

The full details for the hill are:

Group:  Carneddau

Name:  Cefn Cyfarwydd

OS 1:50,000 map:  115

Summit Height:  501.7m (converted to OSGM15)

Summit Grid Reference:  SH 75201 63067

Bwlch Height:  471.0m (converted to OSGM15)

Bwlch Grid Reference:  SH 74708 62751

Drop:  30.7m

For the additions, reclassifications and deletions to Y Pedwarau reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the available and following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

For details on the survey of this hill

Myrddyn Phillips and Aled Williams (July 2019)