Showing posts with label Pt. 524.3m (SN 881 163). Show all posts
Showing posts with label Pt. 524.3m (SN 881 163). Show all posts

Sunday, 20 October 2019

Mapping Mountains – Hill Reclassifications – Yr Uchafion


Pt. 524.3m (SN 881 163) – 500m Sub-Uchaf reclassified to Uchaf

There has been a reclassification to a hill that is listed in the The Welsh Highlands – Uchafion Cymru, through the results of a Trimble GeoXH 6000 survey conducted by Myrddyn Phillips on the 27th July 2019.

Pt. 524.3m (SN 881 163)

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

The Welsh Highlands – Uchafion Cymru – This is the revised draft title for the Welsh 500m P15s list that takes in all hills in Wales at or above 500m in height with 15m minimum drop.  Accompanying the main list are three sub lists, these are; 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub category, with this hill being reclassified from the 500m Sub-Uchaf category, the criteria for which are all Welsh hills at or above 500m in height with 14m or more and below 15m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams with the Introduction to the list being published on Mapping Mountains in November 2015 and an update relating to the list appearing on Mapping Mountains on the 19th June 2019.

As an appropriate name for the hill has not been substantiated either from local enquiry or historic research it is being listed by the point (Pt. 524.3m) notation, and it is adjoined to the Fforest Fawr group of hills, which are situated in the western part of South Wales (Region C, Sub-Region C2), and is positioned with the A4067 road to its west, and has the village of Abercraf (Abercrave) towards the south-west.

This hill was not included when the original list of Welsh 500m P15s that later became known as Yr Uchafion and latterly as The Welsh Highlands – Uchafion Cymru was compiled, as details on contemporary Ordnance Survey maps of the day indicated that it did not have the minimum of 15m of drop required to be included in this list.

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 was conducted by Aled Williams and produced a 524.0m summit height positioned at SN 88113 16370 and a 509.4m bwlch height positioned at SN 87908 16298, giving the hill a drop of 14.6m and thereby confirming its status as a 500m Sub-Uchaf.

Gathering data at the summit of Pt. 524.3m (SN 881 163)

Gathering data at the bwlch of Pt. 524.3m

The summit and bwlch of this hill have now been surveyed by Myrddyn Phillips with the Trimble GeoXH 6000, using the LIDAR summit and bwlch grid references produced by Aled Williams as a guide.  This survey resulted in a 524.3m summit height and a 509.2m bwlch height, with these values giving this hill 15.0m of drop, which is sufficient for it to be reclassified to Uchaf status.


The full details for the hill are:

Group:  Fforest Fawr

Name:  Pt. 524.3m

OS 1:50,000 map:  160

Summit Height:  524.3m (converted to OSGM15)

Summit Grid Reference:  SN 88113 16370

Bwlch Height:  509.2m (converted to OSGM15)

Bwlch Grid Reference:  SN 87908 16298
   
Drop:  15.0m 


For the additions, deletions and reclassifications to The Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:










For details on the survey of this hill

Myrddyn Phillips and Aled Williams (October 2019)



Wednesday, 16 October 2019

Mapping Mountains – Trimble Surveys – Fforest Fawr


27.07.19  Carreg Cadno (SN 874 161), Pt. 529.6m (SN 878 160), Pt. 524.3m (SN 881 163) and Twyn y Ffald (SN 852 160)  

Carreg Cadno (SN 874 161)

With Mark having driven to Welshpool, I continued to Caersŵs where Aled was parked and ready for the continuation south to the southern part of Fforest Fawr, where a number of limestone hills awaited for the three of us, and also the higher hills to the north for Aled and Mark.

We set off walking in warm late morning sunshine from the large parking area at Penwyllt.  I’d visited this area once before in July 2002 when along with Lisa we combined the higher Fan Gyhirych and Fan Fraith with the lower Carreg Cadno and finished the day with a welcome pub meal in Llyswen.

A public footpath strode confidently toward the limestone summits that looked out upon this seldom visited area of Fforest Fawr.  The path continued over a disused tramline, with the northerly section of this later being used as part of my descent route.  Soon afterward the path joined a fence and continued upward with only the last few minutes across summer grasses and limestone rock leading us away from the path and toward the summit of Carreg Cadno.

Heading for the hills

This hill is crowned by a large rock which requires a quick scramble to get to its top, and once there I set the equipment up with the Trimble’s internal antenna aligned with the high point and lay below it as it beeped away gathering its datum points.  Once the allotted data were gathered and stored I switched it off, took a few photos and joined Mark and Aled who were sitting in the pleasing sunshine having a bite to eat.

Mark at the summit of Carreg Cadno

As I wanted to survey the summit and connecting bwlch of four hills, Aled had suggested that he and Mark could leave me to my surveying activities whilst they continued northward toward Fan Gyhirych, with Penwaundwr (SN 907 228) being our rendezvous spot in three to four hours’ time.  Therefore as Aled headed east toward the next limestone summit I followed and watched him gain height toward its top, whilst I headed in to thick grassland to the hill’s connecting bwlch.  As data were gathered Mark passed heading toward Aled, and as the equipment was closed down having gathered the allotted data we waved at one another and that would be the last I saw of them for a number of hours.

Pt. 529.6m (SN 878 160)

The compact area taking in Carreg Cadno also takes in two lower limestone summits, all had been LIDARed by Aled and I now wanted to repeat the process with the Trimble.  The land consists of thick grassland, patches of heather with rubbled limestone, at a contrast to the higher hills immediately to the north.

Gathering data at the bwlch of Pt. 529.6m

I was soon on top of the second summit and had the Trimble set-up and gathering data within a few minutes.  During this a dark mass of threatening cloud had built up to the north and as data were gathered this became darker and loomed over the higher hills ready to unload what looked like a deluge.

Gathering data at the summit of Pt. 529.6m

The next point to survey was the connecting bwlch to a 524m map heighted summit that has an old cairn on top.  The bwlch was a few metres north from a green track that passes over the hills, and whilst the Trimble squatted in the thick grassland atop my rucksack I spotted a couple heading my way on the green track.  They reached me just as the Trimble had gathered its allotted five minutes of data, they stopped and we chatted for a few minutes before I scampered off to switch the equipment off and take a number of photos as the dark mass of cloud bore down on the hills.

Pt. 524.3m (SN 881 163)

Gathering data at the bwlch of Pt. 524.3m

As the Trimble gathered data from the third summit the first raindrops scattered in the breeze.  This felt refreshing after the warmth of the ascent and with a warm breeze skimming across the land and with the grassland swaying in tune it felt good to be out. However, the rain soon increased in strength and once the allotted data were gathered and stored and the equipment switched off and packed away, I put my Goretex on and headed north toward a gravelled track which in time would lead me down to the disused tramway and railway.  But before that I had one more survey to conduct which lay further north.

Gathering data at the summit of Pt. 524.3m

The connecting bwlch of Carreg Cadno sits in thick grassland with a few small puddled bogs squat-like waiting for any unsuspecting walkers who may for whatever reason pass this way, I doubt this often happens as there is no reason why such a place would be visited unless wanting to survey it, which I did.

Gathering data at the bwlch of Carreg Cadno

During the bwlch survey the rain lessened and once back on the track and height regained I stopped to take my Goretex off and enjoyed the rest of the walk unencumbered in the afternoon warmth.  The gravel track led down to a series of grassed switchbacks which give access down to the remains of what is now a disused railway line.  A few minutes to the south lay the connecting bwlch for the final hill of the day; Twyn y Ffald, which is now listed as a Sub-Trichant due to LIDAR analysis conducted by Aled.

Twyn y Ffald (SN 852 160)

The connecting bwlch was positioned close to a barb wired fence amongst wild flowers and swaying grasses.  Whilst data were gathered I stood contemplative in the afternoon warmth and looked out past the survey equipment to the rising bulk of Fan Gyrhirych, which loomed darkly silhouetted in the distance.

Gathering data at the bwlch of Twyn y Ffald

All that remained was to visit and survey the summit of Twyn y Ffald and the continuation of the path beside the old disused railway line brought me to its broad and grassed ridge which bi-passed the depths of the near quarry. 

The summit was a delight, with wind-blown wild flowers madly swaying against the two small fangs of rock which constitutes its high point.  Once my rucksack was wedged between the two rocks and the Trimble balanced on top of it and its internal antenna fixed on top of the highest bit of rock, I waited for the allotted data to be stored and luxuriated myself with the view and watched the movement of grass and flowers as the breeze blew.

Gathering data at the summit of Twyn y Ffald

All that remained was the descent to the quarry floor and a walk back to my car and the drive north to pick Aled and Mark up, who when I arrived, were sitting beside the road in the late afternoon sunshine having been waiting for about ten minutes; not bad timing!



Survey Result:



Carreg Cadno 
 
Summit Height:  538.4m (converted to OSGM15)

Summit Grid Reference:  SN 87423 16132

Bwlch Height:  502.9m (converted to OSGM15)

Bwlch Grid Reference:  SN 88466 17006

Drop:  35.5m

Dominance:  6.60%




Pt. 529.6m 
 
Summit Height:  529.6m (converted to OSGM15)

Summit Grid Reference:  SN 87887 16087

Bwlch Height:  510.4m (converted to OSGM15)

Bwlch Grid Reference:  SN 87705 16096

Drop:  19.1m

Dominance:  3.61%




Pt. 524.3m
  
Summit Height:  524.3m (converted to OSGM15)

Summit Grid Reference:  SN 88113 16370

Bwlch Height:  509.2m (converted to OSGM15)

Bwlch Grid Reference:  SN 87908 16298


Dominance:  2.87%




Twyn y Ffald 
 
Summit Height:  369.2m (converted to OSGM15)

Summit Grid Reference:  SN 85226 16033

Bwlch Height:  342.5m (converted to OSGM15)

Bwlch Grid Reference:  SN 85540 16185

Drop:  26.7m (Sub-Trichant addition)

Dominance:  7.23%








Saturday, 15 April 2017

Mapping Mountains – Hill Reclassifications – Welsh Highlands - Uchafion Cymru


Pt. 524.0m (SN 881 163) - 500m Sub-Uchaf addition

THIS HILL HAS SUBSEQUENTLY BEEN SURVEYED WITH THE TRIMBLE GEOXH 6000 AND RECLASSIFIED TO UCHAF STATUS


There has been an addition 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 that have a minimum drop of 15m, the list is a joint compilation with Aled Williams, with the details relating to this list being published on the Mapping Mountains site in November 2015.

Pt. 524.3m (SN 881 163)

The listing of Yr Uchafion includes three sub lists; the 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub-Uchaf category.  This hill has been included as a 500m Sub-Uchaf, with the criteria for this classification being all Welsh hills at or above 500m in height that have 14m or more and below 15m of drop.

This hill is given a 524m summit spot height on the Ordnance Survey 1:25,000 Explorer map and has bwlch contouring between 510m – 520m, implying that it has insufficient drop to be considered for the 500m Sub-Uchaf category.

The hill is adjoined to the Fforest Fawr group of hills with its Cardinal Hill being Fan Gyhirych (SN 880 191) and is placed in the Region of South Wales (Region C, Sub-Region C2), and is situated with the small community of Glyntawe to its west.

The hill can be accessed via public footpaths from Penwyllt towards its west, or from towards its south-east from the end of a minor road that heads north following the course of the Nedd Fechan.

As the authors do not know either a local or historical name that is appropriate for the hill the point (Pt. 524m) notation is being used, and its inclusion as a 500m Sub-Uchaf is due to analysis of LIDAR data by Aled Williams.  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 gives the hill the following details:


Pt. 524m

Summit Height:  524.0m (converted to OSGM15)

Summit Grid Reference:  SN 88113 16370

Bwlch Height:  509.4m (converted to OSGM15)

Bwlch Grid Reference:  SN 87908 16298

Drop:  14.6m


Therefore, the 524.0m (converted to OSGM15) LIDAR data produced for the summit position at SN 88113 16370 and the 509.4m (converted to OSGM15) LIDAR data produced for the bwlch position at SN 87908 16298 gives this hill 14.6m of drop, which is sufficient for its inclusion as a 500m Sub-Uchaf. 


The full details for the hill are:

Cardinal Hill:  Fan Gyhirych

Summit Height:  524.0m (converted to OSGM15) (LIDAR data)

Name:  Pt. 524.0m

OS 1:50,000 map:  160

Summit Grid Reference:  SN 88113 16370 
  
Drop:  14.6m (converted to OSGM15) (LIDAR data)


The overall total for Yr Uchafion / The Welsh 500m P15s remains at 631 hills with the total for the 500m Sub-Uchaf category now being 26.

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 (April 2017)