Mapping Mountains – Significant Height Revisions – Y Trichant – The 300m Hills of Wales

 

Moel Gwyn Fynydd (SH 736 288) 

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 Moel Gwyn Fynydd (SH 736 288)

The criteria for the list that this height revision applies to are:

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017. 

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

The name the hill is listed by is Moel Gwyn Fynydd, and it is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with a minor road to its west and south, and the A470 road farther to its west, and has the village of Trawsfynydd towards the north north-west. 

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed with a 385m summit height based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating; 386m on 1984 1:50,000 map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR analysis gives the summit height of this hill as 387.1m 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. 

Therefore, the new listed summit height of this hill is 387.1m and this was derived from LIDAR analysis, this is 2.1m higher than the originally listed summit height of 385m 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:  Moel Gwyn Fynydd 

OS 1:50,000 map:  124

Summit Height (New Height):  387.1m (LIDAR)                                                           

Summit Grid Reference:  SH 73674 28884 (LIDAR) 

Bwlch Height:  336.5m (LIDAR) 

Bwlch Grid Reference:  SH 74542 29998 (LIDAR) 

Drop:  50.6m (LIDAR) 

 

Myrddyn Phillips (December 2021)

 

 

 

 

 

 

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

 

Moel Gwyn Fynydd (SH 739 297) 

There has been a Significant Name Change to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Moel Gwyn Fynydd (SH 739 297)

The criteria for the list that this name change applies to are: 

Y Trichant – The 300m Hills of Wales.  Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017. 

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

The hill is adjoined to the Arenig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned with minor roads to its north-east and west, and the A470 road farther to its west, and has the village of Trawsfynydd towards the north north-west. 

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed under the directional name of Moel Gwynfynydd North Top, with an accompanying note stating; Name from hill to the South.

Moel Gwynfynydd North Top

370c

SH739297

124

18

Name from hill to the South

 

During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them, or as in this instance use a directional name based on the name given an adjacent hill to the south on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found. 

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

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales. 

Extract from the Tithe map

The name of Moel Gwyn Fynydd appears on contemporary Ordnance Survey maps adjacent to the 387.1m heighted hill positioned at SH 73674 28884, with the name Gwyn Fynydd relating to a farm to the south-west.  This implies that this hill is a part of the land associated with the farm of Gwyn Fynydd.  The Tithe map was consulted for the boundary taking in the land associated with these two hills, and it substantiates that at the time of the Tithe these two hills were positioned on the same bounded land and therefore the use of the same name for each hill is appropriate. 

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Moel Gwyn Fynydd, and this was derived from the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map with the land boundary confirmed via the Tithe map. 

 

The full details for the hill are: 

Group:  Arenig 

Name:  Moel Gwyn Fynydd 

Previously Listed Name:  Moel Gwynfynydd North Top 

OS 1:50,000 map:  124

Summit Height:  371.0m (LIDAR)                                                           

Summit Grid Reference:  SH 73951 29746 (LIDAR) 

Bwlch Height:  350.3m (LIDAR) 

Bwlch Grid Reference:  SH 73857 29337 (LIDAR) 

Drop:  20.7m (LIDAR) 

 

Myrddyn Phillips (December 2021)