Mapping Mountains – Summit Relocations – The Welsh P15s

 

Cae Tros Ffordd (SH 797 643) 

There has been a Summit Relocation to a hill that is listed in the 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 Tros Ffordd (SH 797 643)

The criteria for the list that this summit relocation 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 name the hill is now listed by is Cae Tros Ffordd, and this was derived from the Tithe map, and it is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned encircled by minor roads with the A470 road farther to its west, and has the town of Llanrwst towards the south.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the accompanying 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 20m of drop, based on the 129m 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 109m bwlch height, based on interpolation of 10m contouring between 100m – 110m. 

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 highest ground on this hill as 127.6m positioned at SH 79758 64295.  However, this is to the top of a raised field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Cae Tros Ffordd (SH 797 643)

The height produced by LIDAR analysis to the natural summit of this hill is 127.1m and is positioned at SH 79756 64305, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or the listing of a new twin summit or de-twinning of a summit, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 127.1m and is positioned at SH 79756 64305, this position matches that of the 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 is approximately 10 metres northward from where the high point of the raised field boundary is positioned. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Cae Tros Ffordd 

OS 1:50,000 map:  115

Summit Height:  127.1m (LIDAR)                                                           

Summit Grid Reference (New Position):  SH 79756 64305 (LIDAR) 

Bwlch Height:  107.9m (LIDAR) 

Bwlch Grid Reference:  SH 79900 64455 (LIDAR) 

Drop:  19.2m (LIDAR) 

 

Myrddyn Phillips (May 2026)