Mapping Mountains – Significant Name Changes – The Welsh P15s

 

Caer Helen (SH 325 780) 

There has been a Significant Name Change 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 Caer Helen (SH 325 780)

The criteria for the list that this name change 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 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The hill is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the coast to its west, the A5 and A55 roads to its north and minor roads to its west and south, and has the village of Llanfiangel-yn-Nhywyn towards the south-west. 

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, but it was documented under the point (Pt. 34m) notation with an estimated c 13m of drop, based on the 34m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 21m bwlch height, based on interpolation of 5m contouring between 20m – 25m. 

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

Since the initial compilation of this list there have been a number of Ordnance Survey maps made available online, some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website, whilst others are current and digitally updated such as the mapping on the Magic Maps and WalkLakes websites. 

One of the mapping resources now available online is the Ordnance Survey series of Six-Inch maps via the National Library of Scotland website.  This mapping preceded the 1:10,000 base maps and has proven an excellent resource for name placement and is much better for this compared to the publicly available Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.  And it is the Six-Inch map that places the name of Caer Helen adjacent to the summit of this hill. 

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the name this hill is now listed by in The Welsh P15s is Caer Helen and this was derived from the Ordnance Survey series of Six-Inch maps. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Caer Helen

Previously Listed Name:  Pt. 34m 

OS 1:50,000 map:  114

Summit Height:  33.9m (LIDAR)                                                           

Summit Grid Reference:  SH 32589 78052 (LIDAR) 

Bwlch Height:  17.4m (LIDAR) 

Bwlch Grid Reference:  SH 32770 78215 (LIDAR) 

Drop:  16.5m (LIDAR) 

 

Myrddyn Phillips (October 2021)