Sunday, 30 October 2016

Mapping Mountains – Trimble Surveys – Bryniau Dyfi


20.10.16  Cribin Fawr (SH 794 152), Waun Oer (SH 785 147, bwlch only), Craig Portas (SH 801 141), Mynydd Gartheiniog (SH 807 142), Mynydd yr Hewyrch (SH 816 150) and Maen Du (SH 822 151)

Cribin Fawr (SH 794 152)

Bwlch Oerddrws is one of the gateways between the east and its gentle sloping hills and the ruggedness of the west at it plunges toward the coast, and at over 360m it is also a convenient starting point to tackle the Aran ridge to its north or part of Bryniau Dyfi to its south.  It was the latter Alan and I visited today, this was the second day out with the Leica and Trimble and I was enthusiastic to see how my right knee dealt with the rigours of two consecutive days in the hills after I twisted it a number of weeks ago.

By the time we parked the Dyfi hills were clear of cloud and the forecast for the remainder of the day was good with only an occasional shower predicted to meander across the country.

I’d only ascended Cribin Fawr once from this high starting point and then used a zig zagging path that takes an almost direct route onto the hill’s northern ridge, today we decided to explore the path that skirts the hill’s eastern ridge and continues westward to gain the ridge north of the summit.

I set off first and toiled in the overly warm conditions as little breeze was present, but progress was made, as it always is, and as I plodded up the final slopes toward the ridge, Alan appeared in front having taken a path directly up the eastern ridge, and by the time I joined him on the summit of Cribin Fawr he had assembled his Leica RX1250 and it was gathering data.

Alan beside the Leica RX1250 at the summit of Cribin Fawr

When on a part of the Berwyn yesterday we’d used a surveying method with the Leica gathering data for approximately 20 minutes, followed by the Trimble set up over the same point for five minutes, and whilst the latter gathered data Alan headed toward the next survey point to set up his Leica and I would later join him to set up my Trimble, this method worked extremely well and we used it again today.

Gathering data with the Trimble GeoXH 6000 at the summit of Cribin Fawr

Once Leica and then Trimble data were gathered I followed the wet path beside a fence past a number of oozing black peat channels and continued south-eastward down to the first bwlch of the day.  We planned on surveying three main bylchau with each having map contours between 550m – 560m, and therefore their respective hills may swap dependent upon which is higher or lower.

By the time I arrived the Leica was gathering another 21 minute data set, this we listed as the critical bwlch for Waun Oer; a 670m map heighted hill to the south-west of Cribin Fawr.  These meetings at each summit and bwlch gave an opportunity to chat and relax as the equipment gathered its data.

Relaxing at the bwlch of Waun Oer


Gathering data with the Trimble GeoXH 6000 at the critical bwlch of Waun Oer

Looming above us were the steep slopes of Craig Portas which is a 605m map heighted Simm, Dewey and Twmpau, and after Alan had packed the Leica away he headed up as I assembled the Trimble, a few minutes later and with data stored I followed him up to the hill’s featureless summit.  During the first few hours of the walk the sky remained a dulled light grey and the ever present threat of rain pervaded as showers were breaking out further west and north, and occasional spits of rain fell our way on the light breeze that ebbed across the hills, but thankfully no persistent rain or heavy shower materialised during the day on the hills we visited.

Craig Portas (SH 801 141)

The summit of Craig Portas is one that must be usually bi-passed unless visited by a bagger as the main path skirts its upper northern cwm, leaving its summit lonely and tussock ridden, today it was surveyed with both the Leica RX1250 and Trimble GeoXH 6000.  After Alan headed off toward the next bwlch, I remained at the summit and waited for the Trimble to gather its customary five minutes of data and stood looking west toward the higher peaks radiating out from Cadair Idris, whose profile always stands out from the Dyfi ridge.

Alan beside the Leica RX1250 at the summit of Craig Portas


Waun Oer (SH 785 147) from the summit of Craig Portas

I soon joined Alan at the next bwlch, this we listed as the critical one for Craig Portas, the bwlch is a tight affair with a few rogue conifers to its immediate south, and a fence and plunging drop to its immediate north, Alan had set his Leica on an extended pole and after it had gathered 20 minutes of data I placed the Trimble on the top of the Leica antenna and noted a 1.12m measurement offset between its internal antenna and the critical point of the bwlch, and the two of us waited for five minutes of data to be gathered.  As the equipment beeped away gathering its individual data points an occasional flash of sunlight brightened the land giving colour to the otherwise dulled surrounds.

Alan setting the Leica RX1250 up at the critical bwlch of Craig Portas, with Mynydd Gartheiniog in the background


Alan beside the Leica RX1250 at the bwlch of Craig Portas


The Trimble GeoXH 6000 gathering data perched on top of the Leica RX1250 at the bwlch of Craig Portas

The next summit along the ridge is another that must usually be bi-passed unless visited by a bagger as its high point is positioned away from the path which continues toward the high point of these hills; Mynydd yr Hewyrch.  We both visited its top, and as I set the Trimble up Alan continued toward the next bwlch.  This hill is a part of Mynydd Gartheiniog and is listed as such in the 500m Twmpau, whilst Michael uses the name of Craig Portas – East Top in his listing of Deweys.  Its summit consists of soft tussocks with a slight path of sorts leading toward its high point.

Ascending Mynydd Gartheiniog from Craig Portas


Dramatic cloud out to the west


Gathering data at the summit of Mynydd Gartheiniog

As I joined Alan at the next bwlch the western sky started showing signs of late afternoon light as dramatic clouds built up out to the west, this late light remained with us for the remainder of the walk giving beautiful conditions over Cadair Idris and succulent autumnal colours on the high Aran.

As data were gathered at the last of the three main bylchau Alan spotted two people near the summit of Craig Portas, they continued toward Mynydd Gartheiniog and eventually disappeared into the day.  Beyond this bwlch lay a fence line heading toward the summit of Mynydd yr Hewyrch; the high point of Bryniau Dyfi, and as the Trimble gathered the last of its allotted 300 datum points I watched Alan make progress up the slope, beside the fence line and disappearing beyond view.

The Trimble GeoXH 6000 gathering data at the critical bwlch of Mynydd Gartheiniog


Looking toward Cadair Idris from the ascent of Mynydd yr Hewyrch

The summit of Mynydd yr Hewyrch consists of a large watery puddle with four grassed peat hags vying for its high point; it is an unusually attractive place and is one that we spent a great amount of time at, as three points were each surveyed with the Leica and Trimble, with each having been Distoed by Alan.

The Leica RX1250 gathering data at one of the three points surveyed atop Mynydd yr Hewyrch


Late afternoon light above Cadair Idris


The Leica RX1250 gathering data at one of the three points surveyed atop Mynydd yr Hewyrch


The Leica RX1250 gathering data at one of three points surveyed atop Mynydd yr Hewyrch


The Trimble GeoXH 6000 gathering data at one of three points surveyed atop Mynydd yr Hewyrch


The Leica RX1250 gathering data at one of three points surveyed atop Mynydd yr Hewyrch


The Trimble GeoXH 6000 gathering data at one of three points surveyed atop Mynydd yr Hewyrch

As the Leica was set up at the third summit point I headed off toward Maen Du, the 674m map heighted top further east which for many years was the recognised high point of the hill.  As I followed the narrow peaty path colour cascaded down across the hills, it was radiant and piecing in its intensity, giving brilliance to the autumnal colour.  I stopped and soaked in the scene as grey shadowed summits were edged against the glowing greens, oranges and autumnal yellows.

On my way toward Maen Du I stopped and surveyed its connecting bwlch with Mynydd yr Hewyrch and then continued to its summit, where Alan joined me a few minutes later.  The summit of Maen Du was the eleventh survey with the Trimble during the day and once data were gathered and the equipment packed away we followed the path southward around the edge of Craig Maesglase and its impressive plunging waterfall.

Long shadows and autumnal colours at the bwlch of Maen Du


Aran Fawddwy
Gathering data at the summit of Maen Du

By now the colour was intense as the last of the days light illuminated Aran Fawddwy, this late intensity of colour only lasts for a few short minutes as the sun sinks ever lower and once gone it was replaced by a subdued light that crept ever onward toward darkness.

Our route down following the escarpment edge above Craig Maesglase


Aran Fawddwy illuminated in late afternoon light


Succulent autumnal colour illuminating Aran Fawddwy


Maen Du with the high Aran in the background

We arrived back at the awaiting car at 6.55pm in dimmed light, having followed the path down onto a lane with the ever present upper reaches of the cwm nestling the Nant Maesglase at its heart, giving us a wonderful darkened and almost silhouetted view up to the ridge line that we had just followed down.


Survey Result:


Cribin Fawr

Summit Height:  658.7m (converted to OSGM15, Trimble GeoXH 6000) 658.8m (Leica RX1250)

Summit Grid Reference:  SH 79452 15285

Drop:  93m

Dominance:  14.12% (based on Leica RX1250 summit and bwlch spot height)


 

Waun Oer

Bwlch Height:  549.4m (converted to OSGM15, Trimble GeoXH 6000) 549.6m (Leica RX1250)

Bwlch Grid Reference:  SH 80115 14398

Drop:  120m  
         
Dominance:  17.98% (based on summit spot height and Leica RX1250 bwlch) 
  



Craig Portas

Summit Height:  603.8m (converted to OSGM15, Trimble GeoXH 6000) 604.1m (Leica RX1250)

Summit Grid Reference:  SH 80154 14120

Bwlch Height:  549.7m (converted to OSGM15, Trimble GeoXH 6000) 549.9m (Leica RX1250)

Bwlch Grid Reference:  SH 80530 14218

Drop:  54.2m (Trimble GeoXH 6000) 54.2m (Leica RX1250)  
       
Dominance:  8.97% (Leica RX1250 summit and bwlch) 
 



Mynydd Gartheiniog

Summit Height:  586.3m (converted to OSGM15)

Summit Grid Reference:  SH 80794 14282

Bwlch Height:  552.8m (converted to OSGM15, Trimble GeoXH 6000) 553.1m (Leica RX1250)

Bwlch Grid Reference:  SH 80951 14527

Drop:  33.3m (Dewey and 500m Twmpau status confirmed) (based on Trimble GeoXH 6000 summit and Leica RX1250 bwlch)

Dominance:  5.67% (based on Trimble GeoXH 6000 summit and Leica RX1250 bwlch) 


 

Mynydd yr Hewyrch

Summit Height:  678.3m (converted to OSGM15, Trimble GeoXH 6000)  678.5m (Leica RX1250) (significant height revision)

Summit Grid Reference:  SH 81697 15003

Drop:  318.0m (based on Trimble GeoXH 6000 bwlch and Leica RX1250 summit)

Dominance:  46.87% (based on Trimble GeoXH 6000 bwlch and Leica RX1250 summit) (Lesser Welsh Dominant status confirmed) 
 



Maen Du

Summit Height:  675.0m (converted to OSGM15)

Summit Grid Reference:  SH 82237 15172

Bwlch Height:  667.8m (converted to OSGM15)

Bwlch Grid Reference:  SH 81910 15043

Drop:  7.2m

Dominance:  1.07% 
 










Friday, 28 October 2016

Mapping Mountains – Significant Name Changes – Y Pedwarau


Fawnog Gnapiog (SN 930 761)

This is the fifty fifth post under the heading of Significant Name Changes, and the following details are in respect of a hill that was surveyed with the Trimble GeoXH 6000 on the 12th March 2016.

The hill is part of the group of hills associated with Pegwn Mawr, this range of hills is situated in the north-eastern part of Mid and West Wales.  The hill is positioned between the small community of Llangurig to the north north-west and the town of Rhaeadr Gwy (Rhayader) to the south south-east.

The Trimble GeoXH 6000 gathering data at the summit of Fawnog Gnapiog

The hill appeared in the 400m P30 list on Geoff Crowder’s v-g.me website under the name of Bryn Titli, which is a name that appeared close to the summit of the hill on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps of the day.  This listing of hills is now co-authored with Aled Williams and known as Y Pedwarau, and the height of the hill had been previously surveyed with a Leica 530 and the drop of the hill was confirmed by the survey with the Trimble. 


Bryn Titli
    497m
    SN930762
    136/147
  214
   

During my early hill listing I paid little regard to name placement on a map, or the meaning of names and to what feature the name was appropriately applied to.  Therefore I prioritised names for listing purposes that I now understand are inappropriate, and Bryn Titli is such an example as this name has been consistently applied by the Ordnance Survey to land taking in a 492.7m (converted to OSGM15) high hill at SN 93383 75719 whose summit is positioned 500 metres to the south-east, whilst a number of different scaled Ordnance Survey maps position the name Fawnog Gnapiog as applicable to land extending to the south south-west from this hill’s summit and importantly this land is a part of this hill.  

Extract from the Ordnance Survey series of Six-Inch maps

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

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

Therefore the name this hill is now listed by in Y Pedwarau (Europeaklist May 2013 and Haroldstreet January 2014) is Fawnog Gnapiog and this was derived from a number of different scaled Ordnance Survey maps that place this name applicable to land extending from the summit of this hill.


The full details for the hill are:

Group:  Pegwn Mawr

Name:  Fawnog Gnapiog

Previously Listed Name:  Bryn Titli
 
Summit Height:  495.7m (converted to OSGM15)

OS 1:50,000 map:  136, 147

Summit Grid Reference:  SN 93038 76169 

Drop:  59.0m





Myrddyn Phillips and Aled Williams (October 2016)









Wednesday, 26 October 2016

Mapping Mountains – Significant Name Changes – Y Pedwarau


Pen Crwn (SN 963 736)

This is the fifty fourth post under the heading of Significant Name Changes, and the following details are in respect of a hill that was surveyed with the Trimble GeoXH 6000 on the 12th March 2016.

The hill is part of the group of hills associated with Pegwn Mawr, this range of hills is situated in the north-eastern part of Mid and West Wales.  The hill is positioned to the south-west of the small community of Pant-y-dŵr and to the north of Rhaeadr Gwy (Rhayader).

The Trimble GeoXH 6000 gathering data at the summit of Pen Crwn

The hill appeared in the 400m P30 list on Geoff Crowder’s v-g.me website under the name of Cefn Lletyhywel, which is a name that appeared close to the summit of the hill on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps of the day.  This listing of hills is now co-authored with Aled Williams and known as Y Pedwarau, and the height and drop of the hill was confirmed by the survey with the Trimble.  


Cefn Lletyhywel
    487m
    SN963736
    136/147
  214
  

During my early hill listing I paid little regard to name placement on a map, or the meaning of names and to what feature the name was appropriately applied to.  Therefore I prioritised names for listing purposes that I now understand are inappropriate, and Cefn Lletyhywel is such an example as this name has been consistently applied by the Ordnance Survey to land below and to the south of the summit of this hill, whilst a number of different scaled Ordnance Survey maps position the name Pen Crwn as applicable to land taking in the summit of this hill.  

Extract from the Ordnance Survey series of Six-Inch maps

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

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

Therefore the name this hill is now listed by in Y Pedwarau (Europeaklist May 2013 and Haroldstreet January 2014) is Pen Crwn and this was derived from a number of different scaled Ordnance Survey maps that place this name applicable to land that takes in the summit of this hill.


The full details for the hill are:

Group:  Pegwn Mawr

Name:  Pen Crwn

Previously Listed Name:  Cefn Lletyhywel 

Summit Height:  486.7m (converted to OSGM15)

OS 1:50,000 map:  136, 147

Summit Grid Reference:  SN 96320 73629
 
Drop:  52.0m





Myrddyn Phillips and Aled Williams (October 2016)









Tuesday, 25 October 2016

Mapping Mountains – Trimble Surveys – Y Berwyn


19.10.16  Foel y Groes (SH 918 235), Moel y Cerrig Duon (SH 923 241), Pt. 605.6m (SH 918 257), Cefn Coch (SH 923 266), Foel y Geifr (SH 937 275), Trum y Gwragedd (SH 941 284, bwlch only) and Cyrniau Nod (SH 988 279, bwlch only)

Moel y Cerrig Duon (SH 923 241)

Parts of the Berwyn have a reputation as being pathless heather bound wonders of torture, whilst other parts are just heather bound.  Today we encountered the former as tussocks; moor grass and heather stretched away in a sea of wilderness which is probably seldom visited except for the occasional sheep gatherer and peak bagger.

The land we visited stretches between Bwlch y Groes and Cwm Hirnant and consists of a number of 500m and 600m hills, all are bulbous affairs of heather and moor where solitude and pathless wandering is the order of the day.

I was out with Alan and we planned to survey everything we could, I met him at the high point of the road that heads from the northern extremity of Llyn Efyrnwy (Lake Vyrnwy) to Y Bala, leaving one car here we continued to Bwlch y Groes, which was where my interest in mountain surveying first cast its hold over me many a year ago when I met Dewi Jones in the car park and he told me that the Nuttall’s had missed a hill from their listing of Welsh mountains, and that he’d surveyed it as having over 15m of drop.  This chance meeting was in the late 1990’s and it led me down a rather unusual but very fulfilling surveying route that was totally unexpected.

As Alan got his autumnal wellies on I positioned the Trimble on top of my rucksack on the edge of the road beside the entrance to the large gravelled and rocky parking area at the top of Bwlch y Groes for the first of what proved to be 14 surveys of the day, this was for the critical bwlch of Moel y Cerrig Duon.

Surveying the critical bwlch of Moel y Cerrig Duon on the edge of the road at Bwlch y Groes

Once data were collected I headed up beside a fence on a narrow path which led toward the summit of Moel y Cerrig Duon, on the way is an Uchaf; Foel Groes, which is also the watershed summit of Wales, as drainage to its south flows into the Afon Dyfi (River Dovey) and Cardigan Bay, whilst drainage to its east flows into the Afon Hafren (River Severn) and the Bristol Channel and drainage to its north flows into the Afon Dyfrdwy (River Dee) and Liverpool Bay.

By the time the Trimble was being set up on the first of two potential summit positions for Foel y Groes, Alan had caught up, and as the second summit position was surveyed he headed off toward the higher summit of Moel y Cerrig Duon leaving me to survey the bwlch between.  This was the start of a system that worked extremely well with Alan heading off to find the next position to survey, leaving me to gather data with the Trimble where he had just surveyed with his Leica; this system remained with us all day.

Gathering data at the summit of Foel y Groes with (L-R) Pt. 605m and Moel y Cerrig Duon in the background

To our north and west the sky massed an ominous grey as dark showers broke out on the higher hills, and although the morning’s rain has ceased the thread of showers remained with us for the remainder of the walk.  The overhead conditions gave us an occasional flash of autumnal colour as deep greys of sky were highlighted by flashes of sunlight brightening an otherwise featureless and monochrome scene of mountain and moor.

When I joined Alan on the summit of Moer y Cerrig Duon his Leica was already gathering data beside the summit cairn, and once 22 minutes of data were collected he set off north-west toward a wilderness of open land that is pathless.  After the Trimble had gathered its customary five minutes of data I followed.  The going was uneven and a little tough in places, but just being there was compensation enough as I’d only joined the hills of Moel y Cerrig Duon with Foel y Geifr once before; with my Mother and her second husband; Barry, many a year ago, my memories from that day was of a great swathe of featureless tough moorland heather bashing, and the course of time has not diminished the nature of this land.

Alan beside the Leica RX1250 at the summit of Moel y Cerrig Duon


Gathering data with the Trimble GeoXH 6000 at the summit of Moel y Cerrig Duon

As I slowly stumbled my way down toward Alan who was assessing the lay of land and choosing his spot for Leica placement at the critical bwlch of Foel y Geifr, I looked toward the west as a great mass of blackened cloud enveloped the Arennig, being high when showers are breaking out is somewhat fulfilling as one can watch their course, this can sometimes be disconcerting as showers are prone to head the same way that you are going, and the going can then get rather wet, but on occasion showers can follow the course of valleys and break out either side of the hill you are on, leaving a pleasing feeling of dryness.

Alan beside the Leica RX1250 at the critical bwlch of Foel y Geifr


Foel y Geifr from its critical bwlch


Gathering data with the Trimble GeoXH 6000 at the critical bwlch of Foel y Geifr

As I joined Alan we had a quick chat before his Leica was packed away and my Trimble assembled over the same spot, next stop was the summit of a 606m map heighted Simm and Dewey, I followed Alan up the hill on pathless moor that developed in to a bed of wet peat toward the summit.  Once Alan’s Leica had gathered the customary 20 minutes of data he headed down to the next bwlch and I positioned the Trimble over the same spot and gathered five minutes of data, and then proceeded down to the next bwlch where the Leica was already in position. 

Nearing the summit of Pt. 605.6m (SH 918 257)


Approaching the summit of Pt. 605.6m (SH 918 257)


The Leica RX1250 gathering data at the summit of Pt. 605.6m


Pt. 605.6m (SH 918 257)


The Trimble GeoXH 6000 gathering data at the summit of Pt. 605.6m

The bwlch of the 606m map heighted hill was soon surveyed before I joined Alan on the summit of Cefn Coch which is listed as a Dewey with 31m of drop, this drop value is based on a rudimentary survey I conducted with Rob Woodall on the 28th October 2001, the result was sent to Michael Dewey who then promoted Cefn Coch to his 500m list of English and Welsh hills.  Since then the Ordnance Survey enlarged mapping on the Geograoh website has become available and shows a 565m spot height at this hill’s bwlch and when coupled with its 594m summit spot height, only gives this hill 29m of map drop, which is insufficient for Dewey qualification, it will be good to finally confirm this hill’s drop value and status, as well as having another comparison of data between my old rudimentary staff and the Trimble.

Once on the summit area Alan set his Leica up on what looked like the high point and suggested that I could Trimble this point and another which looked close in height, each was separated by a small cleft of land, Alan used a Disto to sight from one to the other and confirmed that the further westerly point, where his Leica was now gathering data, was just higher.   The same procedure then took place with the Leica set up first and gathering around 20 minutes of data, and after the Trimble had gathered one set of data at the slightly lower point it was positioned at the same point as the Leica and gathered a further five minutes data set.

Alan's Leica gathering data at the summit of Cefn Coch whilst the Trimble gathers data at what proved to be a lower point


The Trimble GeoXH 6000 gathering data at the summit of Cefn Coch

The bwlch for Cefn Coch proved another wondrous affair of featureless and wild moor where few must wander.  However featureless it proved the critical point was relatively easy to pinpoint and as I joined Alan he had already assembled his Leica RX1250 and it was gathering another 20 minute data set.

Somewhere down there is Alan setting up the Leica RX1250


The Leica RX1250 gathering data at the critical bwlch of Cefn Coch

As the Trimble gathered data at the bwlch, Alan set off toward the summit of Foel y Geifr, the ground looked pathless and we hoped that a semblance of path may exist adjacent to a fence that was later joined and headed toward the last summit of the day.  It was unusual but also pleasing to be left on my own in such landscape, a rather unforgiving place of nothingness except for lingering late afternoon light, a cooling breeze and the chill of solitude and empty moor.

I found the going to the summit of Foel y Geifr to be tough, but thankfully a form of path did exist beside the fence line which strode confidentially up and across the hill.  By the time I reached the summit all I wanted to do was smile and sit down.  This summit has a trig pillar perched at its top with a number of small embedded rocks around its base, one to its north proved the highest and Leica and Trimble data were gathered.

The Leica RX1250 gathering data at the summit of Foel y Geifr

All that remained were two bylchau, the first being that of Trum y Gwragedd and the last being that of Cyrniau Nod.  The former was Leicaed and Trimbled and the latter just Trimbled.  The first bwlch proved another peat laden affair amongst copious amounts of moor grass and heather, and I joined Alan as the Leica gathered another data set.  As I positioned the Trimble on top of my rucksack to give it elevation above its immediate surrounds the light faded to dusk as the sun cast out from behind cloud beyond Aran Benllyn and the high Aran, giving a dramatic display of late evening light.

The high Aran


The Trimble GeoXH 6000 gathering data at the critical bwlch of Trum y Gwragedd


Last burst of sunlight

Just one survey remained and we stumbled our way down the hill to pinpoint the critical bwlch of Cyrniau Nod, which proved another heather and bog bound beauty.  From here it was no more than a few minutes plod up to join the high point of the road above Cwm Hirnant where my car awaited, it had been an excellent day on the hill.

 
The last survey of the day, the fourteenth, at the critical bwlch of Cyrniau Nod


Survey Result:


Foel y Groes

Summit Height:  580.9m (converted to OSGM15)

Summit Grid Reference:  SH 91835 23507

Bwlch Height:  560.5m (converted to OSGM15)

Bwlch Grid Reference:  SH 92028 23791

Drop:  20.4m (500m Sub-Twmpau status confirmed)

Dominance:  3.51% 

 

Moel y Cerrig Duon

Summit Height:  624.3m (converted to OSGM15, Trimble GeoXH 6000) 624.4m (Leica RX1250)

Summit Grid Reference:  SH 92349 24147

Bwlch Height:  545.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 91331 23270

Drop:  79.0m (Leica RX1250 summit and Trimble GeoXH 6000 bwlch)

Dominance:  12.64%  



Pt. 605.6m

Summit Height:  605.3m (converted to OSGM15, Trimble GeoXH 6000)  605.6m (Leica RX1250)

Summit Grid Reference:  SH 91857 25730

Bwlch Height:  558.5m (converted to OSGM15, Trimble GeoXH 6000) 558.8m (Leica RX1250)

Bwlch Grid Reference:  SH 92167 26319

Drop:  46.7m (Trimble GeoXH 6000) 46.8m (Leica RX1250)

Dominance:  7.73% (Leica RX1250 summit and bwlch)   



Cefn Coch

Summit Height:  592.6m (converted to OSGM15, Trimble GeoXH 6000) 592.9m (Leica RX1250)

Summit Grid Reference:  SH 92310 26674

Bwlch Height:  561.4m (converted to OSGM15, Trimble GeoXH 6000) 561.6m (Leica RX1250)

Bwlch Grid Reference:  SH 92501 26927

Drop:  31.2m (Trimble GeoXH 6000) 31.3m (Leica RX1250) (Dewey and 500m Twmpau status confirmed)

Dominance:  5.27% (Leica RX1250 summit and bwlch)   



Foel y Geifr

Summit Height:  626.0m (converted to OSGM15, Trimble GeoXH 6000) 526.2m (Leica RX1250)

Summit Grid Reference:  SH 93710 27524

Bwlch Height:  514.7m (converted to OSGM15, Trimble GeoXH 6000) 514.9m (Leica RX1250)

Bwlch Grid Reference:  SH 91823 24620

Drop:  111.3m (Trimble GeoXH 6000) 111.3m (Leica RX1250)

Dominance:  17.77% (Leica RX1250 summit and bwlch) 

 

Trum y Gwragedd

Bwlch Height:  586.4m (converted to OSGM15, Trimble GeoXH 6000) 586.7m (Leica RX1250)

Bwlch Grid Reference:  SH 93945 27889

Drop:  24.5m (converted to OSGM15, Leica 530 summit and Leica RX1250 bwlch)

Dominance:  4.01% 

 

Cyrniau Nod

Bwlch Height:  487.4m (converted to OSGM15)

Bwlch Grid Reference:  SH 94458 27324

Drop:  179m

Dominance:  26.88%