Mapping Mountains – Hill Reclassifications – Humps

Pentir-bach (SN 739 300) – Subhump reclassified to Hump

This is the thirty fifth in a series of Hill Reclassification posts that detail hills whose status has either been altered in the listing of the Humps (HUndred Metre Prominences) through map study and / or surveys that I have instigated, or it is the recommendation that their status is altered.

Many preceding posts detailing these hill reclassifications to the Humps are retrospective as they were initiated from studying the Ordnance Survey Interactive Coverage Map hosted on the Geograph website, or from surveying with the Trimble GeoXH 6000, or from LIDAR analysis, and for this reclassification that affected the Humps the email I posted on the Tump Yahoo Group forum in relation to this hill was dated 24.11.18.

The listing of Humps was published in book format by Lulu in 2009 and entitled More Relative Hills of Britain, its author; Mark Jackson gives credit to a number of people who contributed toward the formation of this list, these include; Eric Yeaman, Alan Dawson, Clem Clements, Rob Woodall, Bernie Hughes, Pete Ridges and others.  When the list was published in book format there were 2987 Humps listed with their criteria being any British hill that has 100m or more of drop, accompanying the main list is a sub category entitled Subhumps, with the criteria being any British hill that has 90m or more and below 100m of drop.

More Relative Hills of Britain by Mark Jackson

The details for the reclassification appear below:

There has been a reclassification to the listing of the Humps (HUndred Metre Prominences) instigated by LIDAR analysis conducted by Myrddyn Phillips.

This hill was initially listed as a Subhump with c 99m of drop based on the 198m spot height adjoined to a triangulation pillar positioned at SN 73901 30019 and an estimated bwlch height of c 99m based on bwlch contouring at 10m intervals and between 90m – 100m.

However, the advent of LIDAR has meant greater accuracy for summit and bwlch heights and their positions, with LIDAR analysis giving this hill a 198.5m summit height positioned at SN 73918 30015 and a 97.9m bwlch height positioned at SN 74245 30684, with these values giving this hill 100.6m of drop, which is sufficient for it to be reclassified to Hump status.

LIDAR image of Pentir-bach

Pentir-bach is adjoined to the Mynydd Du group of hills and is situated overlooking the Afon Tywi (River Towy) and the A4069 road to its north-west, and is positioned between the village of Llangadog towards its south-west the small town of and Llanymddyfri (Llandovery) towards its north-east.

The reclassification of this hill from Subhump to Hump status was accepted and its new classification augmented in to the listing of the Humps on the 25.11.18.

The full details for the hill are:

Name:  Pentir-bach (as listed in the Humps)

OS 1:50,000 map:  146, 160

OS 1:25,000 map:  12

Summit Height:  198.5m (LIDAR)

Summit Grid Reference:  SN 73921 30020 (LIDAR) (as listed in the Humps)

Bwlch Height:  98.0m (LIDAR) (as listed in the Humps)

Bwlch Grid Reference:  SN 7423 3068 (LIDAR) (as listed in the Humps)

Drop:  100.5m (LIDAR) (as listed in the Humps)

Myrddyn Phillips (February 2019)