Mapping Mountains - Significant Height Revisions - Y Trichant
Ffridd Felen (SH 855 388) - 35th significant height revision
Hill Reclassifications post for Ffridd Felen
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips.
LIDAR image of Ffridd Felen (SH 855 388) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
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, 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 21m of drop, based on the 392m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 371m bwlch height, with the latter based on interpolation of 10m contouring between 370m – 380m that appear on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR analysis gives the summit height of this hill as 395.0m 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 summit height and Ordnance Survey or Harvey map summit spot height, has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR. Also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble or by LIDAR analysis.
Therefore, the new listed summit height of this hill is 395.0m and this was derived from LIDAR analysis, this is 3.0m higher than the previously listed summit height of 392m which appears as a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Arenig
Name: Ffridd Felen
OS 1:50,000 map: 124, 125
Summit Height (New Height): 395.0m (LIDAR)
Summit Grid Reference: SH 85563 38821 (LIDAR)
Bwlch Height: 372.0m (LIDAR)
Bwlch Grid Reference: SH 85597 38395 (LIDAR)
Drop: 23.0m (LIDAR)
Myrddyn Phillips (December 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Pt. 360.1m (SN 604 447) - 34th significant height revision
Hill Reclassifications post for Pt. 360.1m
Significant Name Changes post for Pt. 360.1m
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data and LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Pt. 360.1m (SN 604 447) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m 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 with a summit height of 357m, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR analysis gives the summit height of this hill as 360.1m 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 summit 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 Pt. 360.1m (SN 604 447) |
The full details for the hill are:
Group: Elenydd
Name: Pt. 360.1m
OS 1:50,000 map: 146
Summit Height (New Height): 360.1m (LIDAR)
Summit Grid Reference: SN 60451 44797 (LIDAR)
Bwlch Height: c 324m (interpolation)
Bwlch Grid Reference: SN 61574 45299 (interpolation)
Drop: c 36m (LIDAR summit and interpolated bwlch)
Myrddyn Phillips (October 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Top Field (SO 110 879) - 33rd significant height revision
Significant Name Changes post for Top Field
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
Top Field (SO 110 879) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m 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 with a summit height of 371m, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating; 374m on 1986 1:50,000 map. On the contemporary Ordnance Survey 1:50,000 Landranger map, the summit spot height is now given as 371m.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR image of Top Field (SO 110 879) |
The term Significant Height Revisions applies to any listed hill whose interpolated summit 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 Top Field |
The full details for the hill are:
Group: Cilfaesty
Name: Top Field
OS 1:50,000 map: 136
Summit Height (New Height): 373.8m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SO 11015 87958 (Trimble GeoXH 6000)
Bwlch Height: 346.1m (LIDAR)
Bwlch Grid Reference: SO 11279 88639 (LIDAR)
Drop: 27.7m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (October 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Bryn (SJ 013 427) - 32nd significant height revision
Significant Name Changes post for Bryn
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Bryn (SJ 013 427) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 309m summit height based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR analysis gives the summit height of this hill as 311.75m 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 summit 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 311.8m and this was derived from LIDAR analysis, this is 2.8m higher than the previously listed summit height of 309m which appears as a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Arenig
Name: Bryn
OS 1:50,000 map: 125
Summit Height (New Height): 311.75m (LIDAR)
Summit Grid Reference: SJ 01302 42727 (LIDAR)
Bwlch Height: 265.6m (LIDAR)
Bwlch Grid Reference: SJ 00726 42379 (LIDAR)
Drop: 46.2m (LIDAR)
Myrddyn Phillips (September 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Mynydd Tŷ’r Sais (SH 855 004) - 31st significant height revision
Survey post for Mynydd Tŷ'r Sais
Hill Reclassifications post for Mynydd Tŷ'r Sais
Summit Relocations post for Mynydd Tŷ'r Sais
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by a Trimble GeoXH 6000 survey, prompted by an enquiry from Ronnie Bowron based on detail in the summit analysis programme produced by Joe Nuttall.
Mynydd Tŷ'r Sais (SH 855 004) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m 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 26m of drop, based on the 359m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and the 1:25,000 Explorer map and the 333m 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 |
One of the resources now available online is 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 mapping shows an uppermost 360m ring contour and bwlch contouring much nearer the 330m height when compared to the contouring on the Ordnance Survey 1:25,000 Explorer map.
Another resource now available online is the mapping on 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 Ordnance Survey maps and for this hill a 362m spot height is given on the area of its summit and again the bwlch contouring is much nearer the 330m height when compared to the contouring on the Ordnance Survey 1:25,000 Explorer map.
Extract from the WalkLakes website |
The term Significant Height Revisions applies to any listed hill whose interpolated summit 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 Mynydd Tŷ'r Sais |
The full details for the hill are:
Group: Pumlumon
Name: Mynydd Tŷ’r Sais
OS 1:50,000 map: 135, 136
Summit Height (New Height): 362.2m (converted to OSGM15)
Summit Grid Reference: SH 85514 00483
Bwlch Height: 329.9m (converted to OSGM15)
Bwlch Grid Reference: SH 86220 00690
Drop: 32.2m
Myrddyn Phillips (July 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Ffridd (SH 953 451) - 30th significant height revision
Significant Name Changes post for Ffridd
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
LIDAR image of Ffridd (SH 953 451) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Ordnance Survey 1:50,000 Landranger map |
LIDAR analysis gives the summit height of this hill as 363.6m 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 summit 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 363.6m and this was derived from LIDAR analysis, this is 2.6m higher than the previously listed summit height of 361m which appears as a spot height on the contemporary Ordnance Survey 1:50,000 Landranger map.
The full details for the hill are:
Group: Arenig
Name: Ffridd
OS 1:50,000 map: 116
Summit Height New Height): 363.6m (LIDAR)
Summit Grid Reference: SH 95302 45157 (LIDAR)
Bwlch Height: 338.5m (LIDAR)
Bwlch Grid Reference: SH 94841 45316 (LIDAR)
Drop: 25.1m (LIDAR)
Myrddyn Phillips (June 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Banc (SN 721 762) - 29th significant height revision
Hill Reclassifications post for Banc
Significant Name Changes post for Banc
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
Banc (SN 721 762) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
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, 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 22m of drop based on the 350m summit spot height and the 328m 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. The 350m summit spot height is now shown on the interactive mapping available on the Magic Maps website with the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps only showing an uppermost 340m ring contour.
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Banc |
The term Significant Height Revisions applies to any listed hill whose interpolated summit 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 Banc |
The full details for the hill are:
Group: Elenydd
Name: Banc
OS 1:50,000 map: 135, 147
Summit Height (New Height): 350.9 (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SN 72127 76209 (Trimble GeoXH 6000)
Bwlch Height: 329.1m (LIDAR)
Bwlch Grid Reference: SN 72361 75991 (LIDAR)
Drop: 21.7m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Myrddyn Phillips (May 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Pt. 375m (SJ 256 529) - 28th significant height revision
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data.
The criteria for the list this height revision affects are:
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website the summit height of this hill was listed as 378m with an accompanying note stating; Height from 1986 1:50,000 map. The 378m spot height is the rounded metric equivalent of the 1240ft imperial height that appeared on the summit area of this hill on the Ordnance Survey series of Six-Inch maps.
After the P30 lists were standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was later listed with an estimated c 372m summit height based on interpolation of its uppermost 370m ring contour that appears on the Ordnance Survey 1:25,000 Explorer map. This height was amended as the land taking in the position of the 1240ft / 378m spot height now comprises a part of the Bwlchgwyn Quarry and therefore there is a likelihood this no longer exists.
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the WalkLakes website |
The term Significant Height Revisions applies to any listed hill whose interpolated summit 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 375m and this was derived from data on the WalkLakes website, this is 3m lower than the originally listed height of 378m and 3m higher than the interpolated c 372m summit height that was previously given for this hill.
The full details for the hill are:
Group: Moel y Gamelin
Name: Pt. 375m
OS 1:50,000 map: 117
Summit Height (New Height): 375m (spot height)
Summit Grid Reference: SJ 25652 52980 (hand-held GPS via DoBIH)
Bwlch Height: 338m (spot height)
Bwlch Grid Reference: SJ 25275 52868 (spot height)
Drop: 37m (spot height summit and bwlch)
Myrddyn Phillips (April 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Glog (SJ 114 037) - 27th significant height revision
Significant Name Changes post for Glog
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data and a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
Glog (SJ 114 037) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m 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 c 320m, based on the uppermost contour that appears 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 summit 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 Glog |
The full details for the hill are:
Group: Carnedd Wen
Name: Glog
OS 1:50,000 map: 136
Summit Height (New Height): 315.4m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference: SJ 11434 03700 (Trimble GeoXH 6000)
Bwlch Height: c 253m (interpolation)
Bwlch Grid Reference: SJ 11080 03903 (interpolation)
Drop: c 62m (Trimble GeoXH 6000 summit and interpolated bwlch)
Myrddyn Phillips (March 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Y Dduallt (ST 041 961) - 26th significant height revision
Hill Reclassifications post for Y Dduallt
Summit Relocations post for Y Dduallt
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived by Joe Nuttall who produced a summit analysis programme using LIDAR, and then by LIDAR analysis initially conducted by Jim Bloomer and subsequently by Myrddyn Phillips.
LIDAR image of Y Dduallt (ST 041 961) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m 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 that accompanied the main P30 list, as it was considered not to meet the criteria then used for this sub category.
After the P30 lists were standardised, and interpolated heights and drop values also included, this hill was listed with 21m of drop based on the 354m summit spot height positioned at ST 04088 96112 and the 333m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map. With its adjacent hill positioned at ST 036 958 listed with an estimated c 360m summit height based on the uppermost ring contour 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 summit height produced by LIDAR analysis is 363.0m and this is positioned at ST 04179 96153, this is a relatively dramatic increase in height compared to some revised heights, and it 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 summit 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 363.0m and this was derived from LIDAR analysis, this is positioned at ST 04179 96153 and is 9.0m higher than its previously listed height of 354m which appears as a spot height on the Ordnance Survey 1:25,000 Explorer map.
The full details for the hill are:
Group: Cymoedd Morgannwg
Name: Y Dduallt
OS 1:50,000 map: 170
Summit Height (New Height): 363.0m (LIDAR)
Summit Grid Reference: ST 04179 96153 (LIDAR)
Bwlch Height: 312.2m (LIDAR)
Bwlch Grid Reference: ST 03283 95733 (LIDAR)
Drop: 50.8m (LIDAR)
Myrddyn Phillips (February 2021)
Mapping Mountains - Significant Height Revisions - Y Trichant
Blaen Pathiog (SN 927 820) - 25th significant height revision
Hill Reclassifications post for Blaen Pathiog
Summit Relocations post for Blaen Pathiog
There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.
LIDAR image of Blaen Pathiog (SN 927 820) |
Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
When the original 300m 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 that accompanied the main P30 list, as it was considered not to meet the criteria then used for the main P30 category, and listed with a 377m summit height, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Magic Maps website |
LIDAR summit image of Blaen Pathiog |
The Trimble GeoXH 6000 gathering data at the summit of Blaen Pathiog |
Therefore, this hill’s new listed summit height is 376.3m and this was derived from a Trimble GeoXH 6000 survey, this is positioned at SN 92775 82001 and is 2.7m lower than its previously listed height of 379m which appeared as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and which now appears on the online mapping available on the Magic Maps website.
The full details for the hill are:
Group: Pumlumon
Name: Blaen Pathiog
OS 1:50,000 map: 136
Summit Height (New Height):
376.3m (converted to OSGM15, Trimble GeoXH 6000)
Summit Grid Reference:
SN 92775 82001 (Trimble GeoXH 6000)
Bwlch Height: 343.3m (LIDAR)
Bwlch Grid Reference:
SN 92760 81765 (LIDAR)
Drop: 33.1m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR image of Mynydd Fynnon Wen (SN 724 797) |
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Mynydd Fynnon Wen |
Mynydd Derw Llwydion (SN 904 900) |
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Gathering data during the first Trimble GeoXH 6000 summit survey |
LIDAR summit image of Mynydd Derw Llwydion |
Gathering data during the second Trimble GeoXH 6000 summit survey |
Y Trichant - The 300m Hills of Wales by Myrddyn Phillips |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the WalkLakes website |
Pt. 396.4m (SH 955 525) - 20th significant height revision
Lidar image of Pt. 396.4m (SH 955 525) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Mapping Mountains - Significant Height Revisions - Y Trichant
Cefn Ucaf (SJ 012 461) - 19th significant height revision
Hill Reclassifications post for Cefn Uchaf
Significant Name Changes post for Cefn Uchaf
Summit Relocations post for Cefn Uchaf
LIDAR image of Cefn Uchaf (SJ 012 461) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Cefn Uchaf |
Bryn Gwyn (SJ 213 617) - 18th significant height revision
Survey post for Bryn Gwyn
Gathering data at the the summit of Bryn Gwyn (SJ 213 617) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Magic Maps website |
Cefn Sarnau (SO 014 341) - 17th significant height revision
LIDAR image of Cefn Sarnau (SO 014 341) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Cefn Sarnau |
Mapping Mountains - Significant Height Revisions - Y Trichant
Foel Lus (SH 732 761) - 16th significant height revision
Foel Lus (SH 732 761) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Foel Lus |
Dinas (SH 699 738) - 15th significant height revision
Hill Reclassifications post for Dinas
LIDAR summit image of Dinas (SH 699 738) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the OS Maps website |
Pen Rhiw Warren (ST 214 904) - 14th significant height revision
Hill Reclassifications post for Pen Rhiw Warren
LIDAR image of Pen Rhiw Warren (ST 214 904) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the OS Maps website |
Mynydd y Grug (ST 177 906) - 13th significant height revision
Summit Relocations post for Mynydd y Grug
LIDAR image of Mynydd y Grug (ST 177 906) |
Extract from the old Ordnance Survey 1:25,000 Explorer map |
Extract from the contemporary Ordnance Survey 1:50,000 Landranger map |
Extract from the contemporary Ordnance Survey 1:25,000 Explorer map |
LIDAR summit image of Mynydd y Grug |
Mynydd y Lan (ST 209 923) - 12th significant height revision
Summit Relocations post for Mynydd y Lan
LIDAR image of Mynydd y Lan (ST 209 923) |
The criteria for the two listings that this significant height revision applies to are:
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Ordnance Survey 1:50,000 Landranger map |
When the Welsh Dominant list was originally compiled this hill was listed with 56.43% dominance based on its 381m summit spot height and its 166m bwlch spot height, with the latter appearing on the Ordnance Survey 1:25,000 Explorer map, with these values giving this hill 215m of drop.
LIDAR summit image of Mynydd y Lan |
LIDAR bwlch image of Mynydd y Lan |
The summit height produced by LIDAR analysis and its position in relation to the 385m spot height comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:
Pen y Bigil (SH 576 621) - 11th significant height revision
Survey post for Pen y Bigil
Hill Reclassifications post for Pen y Bigil
Pen y Bigil (SH 576 621) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Ordnance Survey 1:25,000 historical map |
Extract from the Ordnance Survey series of Six-Inch maps |
LIDAR image of Pen y Bigil |
The Trimble GeoXH 6000 gathering data at the summit of Pen y Bigil |
Mapping Mountains - Significant Height Revisions - Y Trichant
Cefn Llanbister (SO 116 733) - 10th significant height revision
Survey post for Cefn Llanbister
Summit Relocation post for Cefn Llanbister
LIDAR image of Cefn Llanbister |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Extract from the Ordnance Survey 1:50,000 Landranger map |
The Trimble GeoXH 6000 gathering data at the summit of Cefn Llanbister which resulted in this hill's significant height revision |
Mapping Mountains - Significant Height Revisions - Y Trichant
Upper Park (SJ 189 052) - 9th significant height revision
Survey post for Upper Park
Summit Relocation post for Upper Park
Y Trichant - Welsh hills at and above 300m and below 400m in height that have 30m minimum drop.
Y Trechol - The Dominant Hills of Wales - These are the Welsh P30 hills whose prominence equal or exceed half that of their absolute height. With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33% or more and below 50% of their absolute height.
The Trimble GeoXH 6000 gathering data at the summit of Upper Park (SJ 189 052) which resulted in this hill's significant height revision |
Mapping Mountains - Significant Height Revisions - Y Trichant
Mynydd yr Heol (SO 107 601) - 8th significant height revision
Survey post for Mynydd yr Heol
Hill Reclassifications post for Mynydd yr Heol
The grazed summit of Mynydd yr Heol (SO 107 601) |
Extract from the Ordnance Survey 1:25,000 Explorer map |
Gathering data with the Trimble GeoXH 6000 from the summit of Mynydd yr Heol which resulted in this hill's significant height revision |
Mapping Mountains - Significant Height Revisions - Y Trichant
Teisen Priodas (SN 820 108) - 7th significant height revision
Survey post for Teisen Priodas
Hill Reclassifications post for Teisen Priodas
Significant Name Changes post for Teisen Priodas
When visiting this hill I made place-name enquiries with two of the remaining six mine workers and was told that the name the hill is known by is Teisen Priodas, which translated into English means the wedding cake, an apt name as the hill has three tiers and is relatively flat on top.
Teisen Priodas is adjoined to the Fforest Fawr group, with its Cardinal Hill being Fan Gyhirych (SN 880 191) and is placed in the Region of South Wales (Region C, Sub-Region C2), with the hill positioned between the small communities of Abercraf (Abercrave) to the north and Y Coelbren towards the east.
Teisen Priodas consists of waste spoil that is now landscaped, and as it is customary for Ordnance Survey maps to show mine workings without any form of contour line the hill had not been classified prior to the analysis of LIDAR data, although the area of this hill’s bwlch does possess contours. The mine is situated on the north-eastern part of the Mynydd y Drum ridge, with the south-western part of this broad ridge still intact having not been mined and possessing a 200m Sub-Twmpau that is listed by the name of Mynydd y Drum.
The survey with the Trimble GeoXH 6000 produced a summit height for Teisen Priodas of 337.9m (converted to OSGM15) which comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:
The Trimble GeoXH 6000 gathering data at the summit of Teisen Priodas (SN 820 108) which confirmed this hill's significant height revision |
Mapping Mountains - Significant Height Revisions - Y Trichant
Moel Llaethbwlch (SJ 113 167) - 6th significant height revision
Survey post for Moel Llaethbwlch
There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 to a hill that is listed in the Y Trichant, with the survey that resulted in this height revision conducted on the 6th April 2017.
The criteria for the listing that this height revision affects are:
Y Trichant - Welsh hills at and above 300m and below 400m in height that have 30m minimum drop. The list is authored by Myrddyn Phillips and the Introduction to the list and its re-naming was published on Mapping Mountains on the 13th May 2017.
The name of the hill is Moel Llaethbwlch and it is situated in the Y Berwyn range of hills which are in the south-east part of North Wales, and the hill is positioned between the town of Llanfyllyn to the north-east and the village of Meifod to the south-east.
The Trimble GeoXH 6000 gathering data at the summit of Moel Llaethbwlch (SJ 113 167) which resulted in this hill's significant height revision |
Penmaen Mawr (SH 704 752) - 5th significant height revision
Survey post for Penmaen Mawr
1st Hill Reclassifications post for Penmaen Mawr
2nd Hill Reclassifications post for Penmaen Mawr
There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 that was conducted on the 14th July 2016 to a hill that is listed in the Y Trichant, with the hill subsequently analysed with LIDAR data by Aled Williams and it is the latter result that is being detailed in this Significant Height Revisions post.
The criteria for the listing that this height revision affects are:
Y Trichant - Welsh hills at and above 300m and below 400m in height that have 30m minimum drop. Sub-Trichant - Welsh hills at and above 300m and below 400m in height that have 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips and the Introduction to the list and its re-naming has been published on Mapping Mountains.
The hill is named Penmaen Mawr and it is situated in the Carneddau range of hills, and is positioned above and to the immediate south of the busy A 55 as it heads westward between the towns of Penmaenmawr and Llanfairfechan, which are situated to the hill’s east and west respectively.
The summit is a part of the hill named Penmaen Mawr and the extended hill has been quarried with its old 1,550ft (472m) map heighted summit now a distant memory as the whole inner section of the summit has been blown apart leaving two remaining tops with this post concentrating on the lower easterly summit.
Mapping Mountains - Significant Height Revisions - Y Trichant
Penmaen Mawr (SH 698 755) - 4th significant height revision
Survey post for Penmaen Mawr
There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 to a hill that is listed in the Y Pedwarau and the Y Trichant, with the survey that resulted in this height revision being conducted on the 14th July 2016.
The criteria for the listings that this height revision affects are:
Y Pedwarau - Welsh hills at and above 400m and below 500m in height that have 30m minimum drop. 300m Double Sub- Pedwarau - Welsh hills at and 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.
Y Trichant - Welsh hills at and above 300m and below 400m in height that have 30m minimum drop. Sub-Trichant - Welsh hills at and above 300m and below 400m in height that have 20m or more and below 30m of drop. The list is authored by Myrddyn Phillips and the Introduction to the list and its re-naming has been published on Mapping Mountains.
The hill is named Penmaen Mawr and it is situated in the Carneddau range of hills, and is positioned above and to the immediate south of the busy A 55 as it heads westward between the towns of Penmaenmawr and Llanfairfechan, which are situated to the hill’s east and west respectively.
The summit area of Penmaen Mawr has been quarried, and prior to the first quarry opening in 1830 and the subsequent resulting expansion of operations the hill was substantially higher, with a 1,550ft (472m) map height given it on the Ordnance Survey Popular and New Popular One-Inch maps, with this height also appearing on the Ordnance Survey Six-Inch map published in 1888.
Penmaen Mawr: 390.4m (converted to OSGM15, Trimble GeoXH 6000) at SH 69865 75523
The Trimble GeoXH 6000 gathering data 0.39m above the summit of Penmaen Mawr (SH 698 755) which resulted in this hill's significant height revision |
Mapping Mountains - Significant Height Revisions - Y Trichant
Cefn Llwydallt (SO 074 409) - 3rd significant height revision
Survey post for Cefn Llwydallt
There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 to a hill that is listed in the Y Trichant, with the following details being retrospective as the survey that resulted in this height revision was conducted on the 29th September 2015. The Y Trichant comprises all Welsh hills at and above 300m and below 400m in height that have 30m minimum drop, with the Introduction to this list and its re-naming being published on Mapping Mountains.
Access to the hill is relatively easy as the summit is situated on open access land and there is a minor road to the north-west next to where the bwlch of the hill is positioned. Alternate routes to the summit can use public footpaths from the north-east, east and south that head toward the open access land, with the summit of the hill positioned amongst small gorse bushes.
Gathering data from the summit of Cefn Llwydallt which resulted in this hill's significant height revision |
Mapping Mountains - Significant Height Revisions - Y Trichant
Coed y Gaer (SO 004 843) - 2nd significant height revision
Survey post for Coed y Gaer
The criteria for the two listings that this height revision affects are:
Y Trichant - The 300m Hills of Wales - these are the Welsh hills at or above 300m and below 400m in height that have a minimum drop of 30m.
Y Trechol - The Dominant Hills of Wales - these are the Welsh P30 hills whose prominence equal or exceed half that of their absolute height. With the criteria for Lesser Dominant status being those addition Welsh P30 hills whose prominence is 33% or more and below 50% of their absolute height.
LIDAR image of Coed y Gaer (SO 004 843) |
Dominance: 33.65% (LIDAR)
Myrddyn Phillips (August 2015)
Old Radnor Hill (SO 251 587) - 1st significant height revision
Survey post for Old Radnor Hill
There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 to the listing of the Y Trichant, with the following details being retrospective as the survey that resulted in this height revision was conducted on 11th January 2014.
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