The
Welsh P15s – Significant Height Revisions
The Welsh P15s are all Welsh
hills that have a minimum of 15m of drop, irrespective of their height. Accompanying the main P15 list is a sub list
entitled; The Welsh Sub-P15s, with the qualification to this sub category being
all Welsh hills with 14m or more and below 15m of drop.
The list is authored by Myrddyn
Phillips and the posts that have appeared on Mapping Mountains detailing the significant
height revisions to the main P15 list and the sub list that are below P20 and
therefore documented in other lists, appear below presented chronologically in
receding order.
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Y Faerdre (SH 784 795) - 21st significant height revision
Hill Reclassifications post for Y Faerdre
Significant Name Changes post for Y Faerdre
There has been a Significant Height Revision to a hill that was listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Y Faerdre (SH 784 795) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Y Faerdre (SH 784 795) |
The full details for the hill are:
Group: Mynydd Hiraethog
Name: Y Faerdre
OS 1:50,000 map: 115
Summit Height (New Height): 93.2m (LIDAR)
Summit Grid Reference: SH 78472 79515 (LIDAR)
Bwlch Height: 81.1m (LIDAR)
Bwlch Grid Reference: SH 78520 79419 (LIDAR)
Drop: 12.2m (LIDAR)
Myrddyn Phillips (November 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Y Boncyn (SH 532 398) - 20th significant height revision
Hill Reclassifications post for Y Boncyn
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Y Boncyn (SH 532 398) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Y Boncyn (SH 532 398) |
The full details for the hill are:
Group: Moel Hebog
Name: Y Boncyn
OS 1:50,000 map: 124
Summit Height (New Height): 66.3m (LIDAR)
Summit Grid Reference: SH 53275 39885 (LIDAR)
Bwlch Height: 51.0m (LIDAR)
Bwlch Grid Reference: SH 53321 39934 (LIDAR)
Drop: 15.3m (LIDAR)
Myrddyn Phillips (September 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Coed Bryn Twr (SH 539 400) - 19th significant height revision
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Coed Bryn Twr (SH 539 400) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Coed Bryn Twr (SH 539 400) |
The full details for the hill are:
Group: Moel Hebog
Name: Coed Bryn Twr
OS 1:50,000 map: 124
Summit Height (New Height): 63.7m (LIDAR)
Summit Grid Reference: SH 53944 40079 (LIDAR)
Bwlch Height: 46.3m (LIDAR)
Bwlch Grid Reference: SN 53944 40155 (LIDAR)
Drop: 17.4m (LIDAR)
Myrddyn Phillips (August 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
March Mynydd Ucha (SO 097 282) - 18th significant height revision
Hill Reclassifications post for March Mynydd Ucha
Significant Name Changes post for March Myydd Ucha
There has been a Significant Height Revision to a hill that was listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of March Mynydd Ucha (SO 097 282) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of March Mynydd Ucha (SO 097 282) |
The full details for the hill are:
Group: Mynydd Epynt
Name: March Mynydd Ucha
OS 1:50,000 map: 161
Summit Height (New Height): 271.1m (LIDAR)
Summit Grid Reference: SO 09744 28233 (LIDAR)
Bwlch Height: 257.4m (LIDAR)
Bwlch Grid Reference: SO 09741 28417 (LIDAR)
Drop: 13.7m (LIDAR)
Myrddyn Phillips (July 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Allt y Geifr (SN 762 284) - 17th significant height revision
Hill Reclassifications post for Allt y Geifr
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Allt y Geifr (SN 762 284) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Allt y Geifr (SN 762 284) |
The full details for the hill are:
Group: Mynydd Du
Name: Allt y Geifr
OS 1:50,000 map: 146, 160
Summit Height (New Height): 171.1m (LIDAR)
Summit Grid Reference: SN 76221 28491 (LIDAR)
Bwlch Height: 156.9m (LIDAR)
Bwlch Grid Reference: SN 76558 28873 (LIDAR)
Drop: 14.2m (LIDAR)
Myrddyn Phillips (June 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Cefn Gwrhyd (SN 737 096) - 16th significant height revision
Hill Reclassifications post for Cefn Gwrhyd
Summit Relocations post for Cefn Gwrhyd
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Cefn Gwrhyd (SN 737 096) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the interactive mapping hosted on the WalkLakes website |
LIDAR summit image of Cefn Gwrhyd (SN 737 096) |
The full details for the hill are:
Group: Mynydd Du
Name: Cefn Gwrhyd
OS 1:50,000 map: 160
Summit Height (New Height): 300.5m (LIDAR)
Summit Grid Reference: SN 73765 09682 (LIDAR)
Bwlch Height: 283.1m (LIDAR)
Bwlch Grid Reference: SN 73543 09172 (LIDAR)
Drop: 17.3m (LIDAR)
Myrddyn Phillips (June 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Cae Cenfas Ucha (SN 751 118) - 15th significant height revision
Hill Reclassifications post for Cae Cenfas Ucha
Summit Relocations post for Cae Cenfas Ucha
Significant Name Changes post for Cae Cenfas Ucha
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Cae Cenfas Ucha (SN 751 118) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Cae Cenfas Ucha (SN 751 118) |
The full details for the hill are:
Group: Mynydd Du
Name: Cae Cenfas Ucha
OS 1:50,000 map: 160
Summit Height (New Height): 182.8m (LIDAR)
Summit Grid Reference: SN 75108 11870 (LIDAR)
Bwlch Height: 164.5m (LIDAR)
Bwlch Grid Reference: SN 75202 12488 (LIDAR)
Drop: 18.3m (LIDAR)
Myrddyn Phillips (May 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Comin Gwauncaegurwen (SN 711 123) - 14th significant height revision
Hill Reclassifications post for Comin Gwauncaegurwen
Significant Name Changes post for Comin Gwauncaegurwen
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Comin Gwauncaegurwen (SN 711 123) |
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:50,000 Landranger map |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the interactive mapping hosted on the WalkLakes website |
LIDAR summit image of Comin Gawuncaegurwen (SN 711 123) |
The full details for the hill are:
Group: Mynydd Du
Name: Comin Gawuncaegurwen
OS 1:50,000 map: 160
Summit Height (New Height): 216.6 (LIDAR)
Summit Grid Reference: SN 71158 12343 (LIDAR)
Bwlch Height: 196.6m (LIDAR)
Bwlch Grid Reference: SN 71330 12592 & SN 71332 12592 (LIDAR)
Drop: 19.98m (LIDAR)
Myrddyn Phillips (April 2024)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Tywyn Niwbwrch (SH 419 625) - 13th significant height revision
Hill Reclassifications post for Tywyn Niwbwrch
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Tywyn Niwbwrch (SH 419 625) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was not included in either the main P15 list or the accompanying P14 sub list, as it possessed no contours of significance on either the Ordnance Survey 1:50,000 Landranger or the 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
One of the mapping resources now available online is the Magic Maps website which hosts an interactive map originated from Ordnance Survey data. This map has many spot heights not on other publicly available Ordnance Survey maps and for this hill a 27m spot height is given on the area of its summit.
Extract from the Magic Maps website |
LIDAR summit image of Tywyn Niwbwrch (SH 419 625) |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 26.9m and this was derived from LIDAR analysis. This is 26.9m higher than detail on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map which do not give any significant contours for this area, but its new listed summit height is similar to the 27m spot height that appears on the interactive mapping on the Magic Maps website.
The full details for the hill are:
Group: Ynys Môn
Name: Tywyn Niwbwrch
OS 1:50,000 map: 114, 115
Summit Height (New Height): 26.9m (LIDAR)
Summit Grid Reference: SH 41937 62552 (LIDAR)
Bwlch Height: 8.4m (LIDAR)
Bwlch Grid Reference: SH 41804 62760 (LIDAR)
Drop: 18.4m (LIDAR)
Myrddyn Phillips (October 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Maes Llwyn (SH 435 920) - 12th significant height revision
Summit Relocations post for Maes Llwyn
Significant Name Changes post for Maes Llwyn
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Maes Llwyn (SH 435 920) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was listed with 25m of drop, based on the 77m summit spot height positioned on or near to a covered reservoir that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the 52m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Maes Llwyn |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 74.0m and this was derived from LIDAR analysis, this is 3m lower than the previous listed summit height of 77m which was based on the spot height positioned on or near to a covered reservoir that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.
The full details for the hill are:
Group: Ynys Môn
Name: Maes Llwyn
OS 1:50,000 map: 114
Summit Height (New Height): 74.0m (LIDAR)
Summit Grid Reference: SH 43593 92022 (LIDAR)
Bwlch Height: 54.9m (LIDAR)
Bwlch Grid Reference: SH 43658 91747 (LIDAR)
Drop: 19.1m (LIDAR)
Myrddyn Phillips (September 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Pen Ucheldref (SH 349 882) - 11th significant height revision
Summit Relocations post for Pen Ucheldref
Significant Name Changes post for Pen Ucheldref
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data and LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Pen Ucheldref (SH 349 882) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was listed with an estimated c 23m of drop, based on an estimated c 90m summit height and an estimated c 67m bwlch height, with both heights based on interpolation of 5m contouring that appears on the Ordnance Survey 1:25,000 Explorer map, with the 85m upper summit contour mistaken for 90m.
Extract from the Ordnance Survey 1:25,000 Explorer map |
The summit height produced by LIDAR analysis is 85.4m and this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 85.4m and this was derived from LIDAR analysis, this is 4.6m lower than the previous listed summit height of c 90m which was based on interpolation of 5m contouring that appears on the Ordnance Survey 1:25,000 Explorer map, with the 85m upper summit contour mistaken for 90m.
The full details for the hill are:
Group: Ynys Môn
Name: Pen Ucheldref
OS 1:50,000 map: 114
Summit Height (New Height): 85.4m (LIDAR)
Summit Grid Reference: SH 34917 88259 (LIDAR)
Bwlch Height: c 67m (interpolation)
Bwlch Grid Reference: SH 35183 88544 (interpolation)
Drop: c 18m (LIDAR summit and interpolated bwlch)
Myrddyn Phillips (August 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Tregynrig Fawr (SH 402 924) - 10th significant height revision
Significant Name Changes post for Tregynrig Fawr
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Tregynrig Fawr (SH 402 924) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was listed with an estimated c 16m of drop, based on an estimated c 64m summit height and an estimated c 48m bwlch height, with both heights based on interpolation of 5m contouring that appears on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Tregynrig Fawr (SH 402 924) |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 66.5m and this was derived from LIDAR analysis, this is 2.5m higher than the previous listed summit height of c 64m which was based on interpolation of 5m contouring that appears on the Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Ynys Môn
Name: Tregynrig Fawr
OS 1:50,000 map: 114
Summit Height (New Height): 66.5m (LIDAR)
Summit Grid Reference: SH 40239 92455 & SH 40241 92457 (LIDAR)
Bwlch Height: 47.1m (LIDAR)
Bwlch Grid Reference: SH 40184 93235 (LIDAR)
Drop: 19.3m (LIDAR)
Myrddyn Phillips (August 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Llanlleiana Park (SH 386 946) - 9th significant height revision
Hill Reclassifications post for Llanlleiana Park
Significant Name Changes post for Llanlleiana Park
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data.
The criteria for the list that this height revision applies to are:
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with an estimated c 16m of drop, based on the 44m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated c 28m bwlch height based on interpolation of 5m contouring between 25m – 30m that appear on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Extract from the Ordnance Survey interactive mapping hosted on the Geograph website |
The full details for the hill are:
Group: Ynys Môn
Name: Llanlleiana Park
OS 1:50,000 map: 114
Summit Height (New Height): 46m (spot height)
Summit Grid Reference: SH 38614 94695 (spot height)
Bwlch Height: c 32m (interpolation)
Bwlch Grid Reference: SH 38606 94628 (interpolation)
Drop: c 14m (spot height summit and interpolated bwlch)
Myrddyn Phillips (July 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Llanlleiana Park (SH 388 946) - 8th significant height revision
Significant Name Changes post for Llanlleiana Park
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data.
The criteria for the list that this height revision applies to are:
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was listed with an estimated c 15m of drop based on an estimated c 52m summit height and an estimated c 37m bwlch height, with both heights based on interpolation of 5m contouring that appears on the Ordnance 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Extract from the Ordnance Survey interactive mapping hosted on the Geograph website |
The full details for the hill are:
Group: Ynys Môn
Name: Llanlleiana Park
OS 1:50,000 map: 114
Summit Height (New Height): 55m (spot height)
Summit Grid Reference: SH 38859 94607 (spot height)
Bwlch Height: c 38m (interpolation)
Bwlch Grid Reference: SH 38902 94509 (interpolation)
Drop: c 17m (spot height summit and interpolated bwlch)
Myrddyn Phillips (July 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Ysgellog & Minffordd (SH 409 912) - 7th significant height revision
Significant Name Changes post for Ysgellog & Minffordd
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Ysgellog & Minffordd (SH 409 912) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was listed with an estimated c 23m of drop based on an estimated c 65m summit height and the 42m 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.
Extract from the Ordnance Survey 1:25,000 Explorer map |
The summit height produced by LIDAR analysis is 60.2m and this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 60.2m and this was derived from LIDAR analysis, this is 4.8m lower than the previous listed summit height of c 65m which was based on interpolation of what was thought to be an uppermost 65m ring contour that appears on the Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Ynys Môn
Name: Ysgellog & Minffordd
OS 1:50,000 map: 114
Summit Height (New Height): 60.2m (LIDAR)
Summit Grid Reference: SH 40921 91218 & SH 40923 91218 & SH 40925 91220 (LIDAR)
Bwlch Height: 41.7m (LIDAR)
Bwlch Grid Reference: SH 40915 91509 (LIDAR)
Drop: 18.5m (LIDAR)
Myrddyn Phillips (July 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Plas Cemlyn (SH 327 936) - 6th significant height revision
Significant Name Changes post for Plas Cemlyn
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Plas Cemlyn (SH 327 936) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Magic Maps website |
The summit height produced by LIDAR analysis is 20.3m and this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
LIDAR summit image of Plas Cemlyn |
The full details for the hill are:
Group: Ynys Môn
Name: Plas Cemlyn
OS 1:50,000 map: 114
Summit Height (New Height): 20.3m (LIDAR)
Summit Grid Reference: SH 32729 93641 (LIDAR)
Bwlch Height: 2.3m (LIDAR)
Bwlch Grid Reference: SH 32454 93517 (LIDAR)
Drop: 18.0m (LIDAR)
Myrddyn Phillips (June 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Wylfa (SH 353 936) - 5th significant height revision
Significant Name Changes post for Wylfa
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Wylfa (SH 353 936) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was listed with an estimated c 18m of drop, based on an estimated c 36m summit height and an estimated c 18m bwlch height, with both heights based on interpolation of 5m contouring that appear on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Wylfa (SH 353 936) |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 38.2m and this was derived from LIDAR analysis, this is 2.2m higher than the previous listed summit height of c 36m which was estimated from interpolation of 5m contouring that appear on the Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Ynys Môn
Name: Wylfa
OS 1:50,000 map: 114
Summit Height (New Height): 38.2m (LIDAR)
Summit Grid Reference: SH 35343 93609 (LIDAR)
Bwlch Height: 20.45m (LIDAR)
Bwlch Grid Reference: SH 35438 93650 (LIDAR)
Drop: 17.8m (LIDAR)
Myrddyn Phillips (June 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Parc y Ffynnon (SH 634 808) - 4th significant height revision
Hill Reclassifications post for Parc y Ffynnon
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Parc y Ffynnon (SH 634 808) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillps |
When the listing that became known as The Welsh P15s was being compiled, this hill was included in the P14 sub list with 14m of drop, based on the 59m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and the 44m 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.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Parc y Ffynnon |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 60.6m and this was derived from LIDAR analysis, this is 1.6m higher than the previous listed summit height of 59m that appears as a spot height on the Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Ynys Môn
Name: Parc y Ffynnon
OS 1:50,000 map: 114, 115
Summit Height (New Height): 60.6m (LIDAR)
Summit Grid Reference: SH 63430 80880 (LIDAR)
Bwlch Height: 44.8m (LIDAR)
Bwlch Grid Reference: SH 63199 81029 (LIDAR)
Drop: 15.8m (LIDAR)
Myrddyn Phillips (June 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Bryn Llwyd (SH 396 644) - 3rd significant height revision
Hill Reclassifications post for Bryn Llwyd
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Bryn Llwyd (SH 396 644) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with an estimated c 15m of drop, based on an estimated c 46m summit height and an estimated c 31m bwlch height, with both heights based on interpolation of 5m contouring that appear on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Bryn Llwyd |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, this hill’s new listed summit height is 43.4m and this was derived from LIDAR analysis, this is 2.6m lower than the previous listed summit height of c 46m which was based on interpolation of the uppermost 45m ring contour that appears on the Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Ynys Môn
Name: Bryn Llwyd
OS 1:50,000 map: 114
Summit Height (New Height): 43.4m (LIDAR)
Summit Grid Reference: SH 39665 64415 (LIDAR)
Bwlch Height: 28.6m (LIDAR)
Bwlch Grid Reference: SH 39795 64510 (LIDAR)
Drop: 14.9m (LIDAR)
Myrddyn Phillips (May 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Craig Dinas (SH 280 772) - 2nd significant height revision
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Craig Dinas (SH 280 772) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
When the listing that became known as The Welsh P15s was being compiled, this hill was listed with an estimated c 16m of drop, based on the 19m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 3m bwlch height based on interpolation of 5m contouring between 0 – 5m.
Extract from the Ordnance Survey 1:25,000 Explorer map |
The summit height produced by LIDAR analysis is 20.0m and this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
LIDAR summit image of Craig Dinas |
The full details for the hill are:
Group: Ynys Môn
Name: Craig Dinas
OS 1:50,000 map: 114
Summit Height (New Height): 20.0m (LIDAR)
Summit Grid Reference: SH 28016 77284 (LIDAR)
Bwlch Height: 3.3m (LIDAR)
Bwlch Grid Reference: SH 27937 77186 (LIDAR)
Drop: 16.7m (LIDAR)
Myrddyn Phillips (May 2021)
Mapping Mountains - Significant Height Revisions - The Welsh P15s
Tomen y Mur (SH 705 386) - 1st significant height revision
Hill Reclassifications post for Tomen y Mur
There has been a Significant Height Revision to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
Tomen y Mur (SH 705 386) |
The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019.
The Welsh P15s by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the WalkLakes website |
LIDAR image of Tomen y Mur (SH 705 386) |
The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey or Harvey map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
The Trimble GeoXH 6000 gathering data at the summit of Tomen y Mur |
The full details for the hill are:
Group: Arenig
Name: Tomen y Mur
OS 1:50,000 map: 124
Summit Height (New Height): 303.2m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SH 70544 38679 (Trimble GeoXH 6000)
Bwlch Height: 288.1m (LIDAR)
Bwlch Grid Reference: SH 70674 38754 (LIDAR)
Drop: 15.1m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (April 2021)
No comments:
Post a Comment