Showing posts with label Banc yr Ŵyn. Show all posts
Showing posts with label Banc yr Ŵyn. Show all posts

Thursday, 1 September 2022

Mapping Mountains – Trimble Surveys – Banc Llechwedd Mawr


09.07.22  Banc yr Ŵyn (SN 741 902) 

Banc yr Ŵyn (SN 741 902)

The only time I had visited this hill was 22 years ago in August 2000, during a four hill Dewey walk taking 2 hours 50 minutes.  I have slowed since those heady days when hills were easy affairs to get up.  Nowadays my hill walking is more circumspect, with route, distance and amount of ascent being factors that all too easily keep me away from the higher hills.  Although my pace has slowed, the fact that I’ve visited the higher Welsh hills on a multitude of occasions is also a determining factor and as I always enjoy venturing on to new ground, it is always a pleasure to visit new hills.

Earlier in the morning Aled and I had visited Disgwylfa Fawr (SN 737 847) and Disgwylfa Fach (SN 756 838).  By the end of the walk the conditions were warming to an uncomfortable degree, therefore the hills we planned on now visiting consisted of small walks and we chose wisely with an ascent of Banc yr Ŵyn from the convenience of its forest track to the north proving ideal as my last walk of the day.

It took a long time to drive from the track beside Llyn Syfydrin to the track heading toward the forestry that surrounds Banc yr Ŵyn.  However, the land hereabouts is stunning in its simplicity with openness predominating, with lakes and hills adding depth and perspective to the landscape.

Having driven on the track leading in to the forestry Aled navigated as I continued toward the junction of tracks with a narrower one leading south toward the summit of the hill, it was here that we parked.

Leaving the car we followed the track as it headed confidently southward, gaining height through dappled light that cast down from a deep blue sky.  The track soon led toward the upper, open hillside and nestled its way on the eastern side of the summit ridge before reaching close to the high point of the hill. 

LIDAR image of Banc yr Ŵyn (SN 741 902)

Prior to visiting the hill Aled and then I had LIDARed it.  The bwlch only has partial LIDAR coverage with its critical point just missing LIDAR.  However, its summit is covered and as the area taking in its high point consists of long grass at this time of year I knew it would be all too easy to miss the exact high point with the Trimble placement. 

Heading up the track leading to the summit

Gathering data at the summit of Banc yr Ŵyn

I soon had the Trimble set up gathering summit data and joined Aled sitting in thick grass looking out toward the Sub-Pedwar of Castell, which now has its upper section felled of conifers.  It looked a fine hill from this direction.  It was good to rest and enjoy the brisk breeze as it skimmed across the upper hill.  For me the uphill of the day was now over, which was a relief as conditions were decidedly warm and would continue to be so for a number of hours to come. 

Castell from Banc yr Ŵyn

Approaching the car at the end of another good, albeit hot day on the hill

Once the Trimble had gathered its allotted data I switched it off, took a few photographs and packed it away.  Leaving the summit we reversed our inward route down the track to the awaiting car.  It had been good to be out in blissful sunny conditions, with the hills chosen just giving enough for the day, without the warming conditions becoming too torturous. 

 

Survey Result: 

 

Banc yr Ŵyn

Summit Height:  501.7m (LIDAR)

Summit Grid Reference:  SN 74195 90213 (LIDAR)

Bwlch Height:  c 428m (interpolation)

Bwlch Grid Reference:  SN 74031 90845 (interpolation)

Drop:  73.7m (LIDAR summit and interpolated bwlch)

Dominance:  14.69% (LIDAR summit and interpolated bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

  

Thursday, 11 May 2017

Mapping Mountains – Hill Reclassifications – Welsh Highlands - Uchafion Cymru


Banc yr Ŵyn (SN 771 923) – Double Sub-Uchaf deletion

There has been a reclassification to the listing of Yr Uchafion instigated from analysis of LIDAR data by Aled Williams.  Yr Uchafion is the draft title for a list of the Welsh 500m P15s that takes in all hills in Wales at or above 500m in height that have a minimum drop of 15m, the list is a joint compilation between Myrddyn Phillips and Aled Williams, and details relating to this list were published on the Mapping Mountains site in November 2015.

Accompanying the main Yr Uchafion list are three sub lists; 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub-Uchaf categories, with the reclassification of this hill affecting the Double Sub-Uchaf category, with the criteria for inclusion to this sub category being Welsh hills at or above 490m and below 500m in height that have 14m or more and below 15m of drop.

Prior to analysis of LIDAR data by Aled the hill was listed with c 14m of drop based on the 491m summit spot height that appears on the Ordnance Survey enlarged mapping hosted on the Geograph website and an estimated bwlch height of c 477m based on bwlch contouring between 470m – 480m.

The hill is situated in the Pumlumon group with its Cardinal Hill being Pen y Darren (SN 764 942) and is placed in the Region of Mid and West Wales (Region B, Sub-Region B2), and in Welsh terms it is a long way away from any small community.

As the hill is immersed in conifer plantation a route to its summit cannot be advised, although if wanting to visit waiting for the trees to be felled may be the most sensible and easiest option.

The name of the hill is Banc yr Ŵyn and its deletion from the ranks of Double Sub-Uchaf is due to the analysis of LIDAR data by Aled.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data for the bwlch (summit not covered) gives the hill the following details:


Banc yr Ŵyn

Summit Height:  491m

Summit Grid Reference:  SN 77182 92335

Bwlch Height:  478.1m

Bwlch Grid Reference:  SN 77031 92373

Drop:  13m


Therefore, the 491m summit spot height at SN 77182 92335 and the 478.1m LIDAR data produced for the bwlch position at SN 77031 92373 gives this hill 13m of drop which is insufficient for it to retain its status as a Double Sub-Uchaf.


The full details for the hill are:

Cardinal Hill:  Pen y Darren

Summit Height:  491m

Name:  Banc yr Ŵyn

OS 1:50,000 map:  135

Summit Grid Reference:  SN 77182 92335 
  
Drop:  13m (OS summit spot height and LIDAR bwlch data)


The overall total for Yr Uchafion / The Welsh 500m P15s is now 631 hills with the total for the Double Sub-Uchaf category now being 5.

For the additions, reclassifications and deletions to Yr Uchafion / The Welsh 500m P15s reported on Mapping Mountains please consult the following Change Registers:













Myrddyn Phillips and Aled Williams (May 2017)