Wednesday, 3 February 2016

Mapping Mountains – Hill Reclassifications – 200m Twmpau

Broniarth (SJ 166 120) - 200m Sub-Twmpau addition

There has been a confirmation of a new addition to the Sub category within the 200m Twmpau (thirty welsh metre prominences and upward) hill list instigated by a survey with the Trimble GeoXH 6000.   The hill is situated between the small community of Meifod to its north-west and that of Maesmawr to its south-east and is part of the Carnedd Wen range of hills.

These details are retrospective, as the Trimble GeoXH 6000 survey that resulted in this hill’s confirmation as a 200m Sub- Twmpau was conducted on the 20th January 2016 on a beautiful crisp winter day in good, dry and sunny conditions.

The hill can be easily accessed from its south where a narrow lane crosses from south-west to north-east across its southerly flank.  This would be a short visit of no more than a few minutes, so combining the hill with some of its neighbours is recommended.  However, permission should be sought for those wishing to visit as the summit is not on open access land.

The hill is unnamed on current Ordnance Survey 1:25,000 Explorer maps but is part of land known locally as Broniarth and which appears on some Ordnance Survey maps as an extended name of either Broniarth or Broniarth Hill.

This is a confirmation of this hill’s addition to the 200m Sub-Twmpau ranks as current Ordnance Survey enlarged mapping on the Geograph website has a 247m spot height on this hill’s bwlch, with the summit having a 268m spot height on the Ordnance Survey 1:25,000 Explorer map and the enlarged map hosted on the Geograph website.  These values give the hill 21m of drop, which compares favourably with the Trimble survey of 21.5m of drop.

The survey with the Trimble GeoXH 6000 resulted in a 267.9m (converted to OSGM15) summit height and a 246.5m (converted to OSGM15) bwlch height, giving this hill 21.5m of drop and confirming its entry in to the 200m Sub-Twmpau ranks.

The full details for the hill are:

Cardinal Hill:  Carnedd Wen

Summit Height:  267.9m (converted to OSGM15)

Name:  Broniarth

OS 1:50,000 map:  125

Summit Grid Reference:  SJ 16648 12055

Drop:  21.5m (converted to OSGM15)

Broniarth (SJ 166 120) 200m Sub-Twmpau status now confirmed by the Trimble GeoXH 6000

For details on the survey that resulted in this hill being confirmed as a 200m Sub-Twmpau please click {here}

Myrddyn Phillips (January 2016)

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