Mapping Mountains - Summit Relocations - Y Pellennig - The Remotest Hills of Wales
Esgair Llyn Du (SN 769 620) - 5th summit relocation
Survey post for Esgair Llyn Du
There has been a Summit Relocation to a hill that is listed in the Welsh Highlands – Uchafion Cymru and Y Pellennig – The Remotest 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.
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Esgair Llyn Du (SN 769 620) |
The criteria for the two listings that this summit relocation applies to are:
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Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips |
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Y Pellennig - The Remotest Hills of Wales by Myrddyn Phillips and Aled Williams |
The name the hill is listed by is Esgair Llyn Du 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-west and south, and has the small community of Pontrhydfendigaid towards the north-west and the town of Tregaron towards the west south-west.
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Extract from the Ordnance Survey 1:25,000 Explorer map |
When the 1st edition of the Y Pellennig – The Remotest Hills of Wales was published by Europeaklist in April 2015, this hill was listed with 3.075km of remoteness and 20m of drop, based on the 534m summit spot height positioned at SN 767 617 and the 514m bwlch spot heights that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, with this mapping giving two positions of equal height for the bwlch.
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Extract from the interactive mapping hosted on the WalkLakes website |
The Ordnance Survey Vector Map Local hosted on the Geograph website gave the higher spot height to the middle of three larger 530m map contour rings, with the southerly and middle ring contours subsequently surveyed with the Trimble GeoXH 6000. However, the interactive mapping hosted on the WalkLakes website indicates that the most northerly of these is the higher.
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The Trimble GeoXH 6000 set-up position at the southerly of the three tops |
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The Trimble GeoXH 6000 set-up position at the central of the three tops |
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At the northerly of the three tops and the summit of Esgair Llyn Du |
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 results from these surveys are given below:
LIDAR for northerly summit: 532.849m at SN 76930 62044
LIDAR for central summit: 532.729m at SN 76768 61773
Trimble GeoXH 6000 for central summit: 532.552m at SN 76770 61772
LIDAR for southerly summit: 532.020m at SN 76691 61642
Trimble GeoXH 6000 for southerly summit: 531.914m at SN 76691 61642
The 532.8m summit height produced by LIDAR analysis and its position in relation to the previously listed summit comes within the parameters of the Summit Relocations used within this page heading, these parameters are:
The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.
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LIDAR image of Esgair Llyn Du (SN 769 620) |
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LIDAR summit image of Esgair Llyn Du (SN 769 620) |
Therefore, the summit height produced by LIDAR analysis is 532.8m and this is positioned at SN 76930 62044. This position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, but a 532m spot height appears in this position on the interactive mapping hosted on the WalkLakes website and is approximately 440 metres north-eastward from where the originally listed summit is positioned and approximately 300 metres north-eastward from where the previously listed summit is positioned, resulting in its remoteness being amended from 3.075km to 2.925km.
The full details for the hill are:
Group: Esgair Wen
Name: Esgair Llyn Du
OS 1:50,000 map: 146, 147
Summit Height: 532.8m (LIDAR)
Summit Grid Reference: SN 76930 62044 (LIDAR)
Bwlch Height: 513.8m (LIDAR)
Bwlch Grid Reference: SN 76942 61196 (LIDAR)
Drop: 19.0m (LIDAR)
Remoteness: 2.925 km
Myrddyn Phillips and Aled Williams (November 2023)
Mapping Mountains - Summit Relocations - Y Pellennig - The Remotest Hills of Wales
Ynys Bery (SM 701 219) - 4th summit relocation
There has been confirmation of the higher summit of a twin map topped hill that is being detailed under the Summit Relocations heading, and the hill is listed in the 30-99m Twmpau, Y Trechol – The Dominant Hills of Wales and Y Pellennig – The Remotest Hills of Wales, with the summit height and its location confirmed by LIDAR analysis conducted by Aled Williams.
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LIDAR image of Ynys Bery. 1m contour (black), 10m contour (red) and sea level (yellow) |
The criteria for the three listings that this summit relocation applies to are:
30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.
Y Trechol - The Dominant Hills of Wales - Welsh P30 hills whose prominence equal or exceed half that of their absolute height. With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height, with the Introduction to the Mapping Mountains publication of this list appearing on the 3rd December 2015.
The name of the hill is Ynys Bery and as its name implies it is an island, and it is adjoined to the Carn Llidi group of hills which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned to the south of the larger Ynys Dewi.
This hill was originally listed in the Welsh 30-99m P30 hills published on Geoff Crowder’s v-g.me website, with a 71m summit height and an accompanying note stating; Two tops of same height. The 71m summit height appears as a spot height given to two separate tops on the Ordnance Survey 1:25,000 Explorer map with these positioned at SM 70058 21863 and SM 70183 21965.
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Extract from the Ordnance Survey 1:25,000 Explorer map |
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Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website |
The details for this hill were reassessed when the Ordnance Survey Vector Map Local hosted on the Geograph website became available online; this map is entitled the Interactive Coverage Map and the two twin map heighted 71m summits were again shown.
However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
LIDAR analysis confirms that the north-easterly of these two summits is the higher and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:
The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct. As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.
Therefore, the summit height produced by LIDAR analysis is 72.0m and is positioned at SM 70182 21959, this position is given a 71m spot height on the Ordnance Survey 1: 25,000 Explorer map and is approximately 150 metres north-east from where the other twin map heighted summit is positioned which LIDAR analysis gives as 71.9m at SM 70056 21859.
The full details for the hill are:
Group: Carn Llidi
Name: Ynys Bery
OS 1:50,000 map: 157
Summit Height: 72.0m (LIDAR)
Summit Grid Reference (new position): SM 70182 21959 (LIDAR)
Bwlch Height: N/A, sea level
Bwlch Grid Reference: N/A, sea level
Drop: 72.0m (LIDAR)
Dominance: 100.00% (LIDAR)
Remoteness: 3.925 km
Myrddyn Phillips and Aled Williams (July 2019)
© Crown: CHERISH PROJECT 2019. Produced with EU funds through the Ireland Wales Co-operation Programme 2014-2020. All material made freely available through the Open Government Licence.
Mapping Mountains - Summit Relocations - Y Pellennig - The Remotest Hills of Wales
Foel Cedig (SH 981 283) - 3th summit relocation
Survey post for Foel Cedig
There has been a Summit Relocation to a hill that is listed in the Yr Uchafion, the 600m Twmpau and Y Pellennig – The Remotest Hills of Wales with the summit height, its location and drop of the hill being confirmed by a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips with the bwlch surveyed on the 19th October 2016 and the summit on the 16th August 2018.
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Foel Cedig (SH 981 283) on the left and Cyrniau Nod (SH 988 279) on the right |
The criteria for the three listings that this summit relocation applies to are:
Yr Uchafion – Welsh hills at or above 500m in height that have 15m minimum drop. The list is co-authored by Myrddyn Phillips and Aled Williams, with the Introduction to this list appearing on Mapping Mountains on the 4th November 2015.
600m Twmpau – Welsh hills at or above 600m and below 700m in height that have 30m minimum drop, with an accompanying sub category entitled the 600m Sub-Twmpau consisting of all Welsh hills at or above 600m and below 700m in height that have 20m or more and below 30m of drop. With the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. The list is authored by Myrddyn Phillips.
Y Pellennig – The Remotest Hills of Wales - Welsh hills whose summit is at least 2.5km from the nearest paved public road and the hill has a minimum 15m of drop, the list is a joint compilation between Myrddyn Phillips and Aled Williams and is available as a downloadable e-booklet or print-booklet version on Mapping Mountains Publications with the up-to-date master list available on the Mapping Mountains site in Google Doc format.
The name of the hill is Foel Cedig, and it is adjoined to the Y Berwyn range of hills, which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and is positioned to the north of Llyn Efyrnwy (Lake Vyrnwy) and has the town of Y Bala towards the north-west.
As the summit of the hill is a part of designated open access land it can be approached from various directions. However, the easiest approach is from the north-west where a track contours the moorland and it is only a short walk from this point to the summit of the hill.
When the qualifying summit for the Yr Uchafion, 600m Twmpau and Y Pellennig – The Remotest Hills of Wales was first listed it was given to the hill named Cyrniau Nod which is positioned at SH 988 279 and listed with a 666m summit height which appears as a spot height on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. Whilst the summit of Foel Cedig which is positioned at SH 981 283 is given a 666m height on these same maps.
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Extract from the Ordnance Survey 1:25,000 Explorer map |
As the surveying technique that produced these two spot heights has a +/- 3m margin of uncertainty applied to it, it meant that Foel Cedig could in fact be higher than Cyrniau Nod, therefore both hills were surveyed with the Trimble GeoXH 6000.
The results from these two surveys are given below:
Foel Cedig: 667.417m at SH 98170 28327
Cyrniau Nod: 666.207m at SH 98847 27920
Since the qualifying summit has been relocated to Foel Cedig this has also affected the lists of Marilyns, Humps, Simms, Hewitts, Nuttalls and Tumps, with Alan Dawson as list author of the Marilyns, Simms and Hewitts having accepted this result the other list authors soon followed suit.
A subsequent Leica GS15 survey conducted by John Barnard and Graham Jackson on the 15th September 2018 resulted in the following:
Foel Cedig: 667.479m at SH 98170 28327
Cyrniau Nod: 666.234m at SH 98847 27918
Data sets of ten and eleven minutes were collected with the Trimble GeoXH 6000, whilst 122 and 121 minute data sets were collected with the Leica GS15.
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The Trimble GeoXH 6000 gathering data at the summit of Foel Cedig with Cyrniau Nod in the background |
The 667.4m summit height produced by the Trimble GeoXH 6000 survey and its position in relation to that of Cyrniau Nod comes within the parameters of the Summit Relocations used within this page heading, these parameters are:
The term Summit Relocations applies to any listed hill whose summit meets the following criteria; where there are a number of potential summit positions within close proximity and the highest point is not where previously given, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist, or when the summit of the hill is in a different field compared to where previously given, or when the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct. As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 Explorer map is being prioritised in favour of the 1:50,000 Landranger map for detailing these relocations.
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The Trimble GeoXH 6000 gathering data at the summit of Cyrniau Nod with Foel Cedig in the background on the left |
The summit height produced by the Trimble GeoXH 6000 survey is 667.4m and is positioned at SH 98170 28327, this position is approximately 800 metres north-west from where the old listed summit of Cyrniau Nod is positioned.
The full details for the hill are:
Group: Y Berwyn
Name: Foel Cedig
OS 1:50,000 map: 125
Summit Height: 667.4m (converted to OSGM15)
Summit Grid Reference (new position): SH 98170 28327
Bwlch Height: 487.4m (converted to OSGM15)
Bwlch Grid Reference: SH 94458 27324
Drop: 180.0m (converted to OSGM15)
Remoteness: 3.200 km
Myrddyn Phillips and Aled Williams (January 2019)
Mapping Mountains - Summit Relocations - Y Pellennig - The Remotest Hills of Wales
Esgair Cerrig (SN 952 432) - 2nd summit relocation
Survey post for Esgair Cerrig
Significant Name Changes post for Esgair Cerrig
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