Wednesday, 19 December 2018

Mapping Mountains – Hill Reclassifications – 30-99m Twmpau


West Park (SR 940 990) – 30-99m Sub-Twmpau reclassified to 30-99m Twmpau

There has been confirmation of a reclassification to the list of 30-99m Twmpau due to LIDAR analysis conducted by Myrddyn Phillips.

The criteria for the listing that this reclassification applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

LIDAR image of West Park

When the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill appeared in the accompanying Hills to be surveyed sub list as it did not meet the criteria then used for the main P30 list; however this sub list has now been standardised and interpolated heights also included in the main P30 and the accompanying sub list.

When this list was standardised and interpolated heights also included this hill was listed with an estimated c 30m of drop, based on an estimated c 82m summit height and an estimated bwlch height of c 52m based on 5m contouring on the Ordnance Survey 1:25,000 Explorer map.

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

The bounded land where the summit of this hill is situated is named as West Park on the Tithe map, and this is the name the hill is now listed by, and it is adjoined to the Brandy Hill group of hills, which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned between the B roads of the 4320 to the north and the 4319 to the south, and has the town of Penfro (Pembroke) towards the north-east.

If wanting to visit this hill permission to do so should be sought as it is not a part of designated open access land, for those wishing to do so the most convenient approach would be from a minor road to the west of the summit.

The confirmation of this reclassification is due to LIDAR analysis conducted by Myrddyn Phillips.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

The LIDAR analysis gives the hill the following details:


Name:  West Park

Summit Height:  81.7m

Summit Grid Reference:  SR 94023 99001

Bwlch Height:  51.3m

Bwlch Grid Reference:  SR 94747 99655

Drop:  30.4m


Therefore, the 81.7m LIDAR analysis for the summit position at SR 94023 99001 and the 51.3m LIDAR analysis for the bwlch position at SR 94747 99655 gives this hill 30.4m of drop, which confirms its 30-99m Twmpau status.


The full details for the hill are:

Group:  Brandy Hill

Name:  West Park

OS 1:50,000 map:  158

Summit Height:  81.7m (LIDAR)

Summit Grid Reference:  SR 94023 99001 (LIDAR)

Bwlch Height:  51.3m (LIDAR)

Bwlch Grid Reference:  SR 94747 99655 (LIDAR)

Drop:  30.4m (LIDAR)


Myrddyn Phillips (December 2018)






No comments:

Post a Comment