Showing posts with label Carnedd Iago. Show all posts
Showing posts with label Carnedd Iago. Show all posts

Wednesday, 10 June 2020

Mapping Mountains – Trimble Surveys – Arenig Fach


07.02.20  Carnedd Iago (SH 782 406), only bwlch surveyed

The summit of Carnedd Iago is easily reached if heading to it from the convenience of the B4391 to its south.  Otherwise its summit is a prize to be savoured as it forms a part of the Y Migneint; this area comprises wild moorland that stretches for many miles where open moors and bog meet.  I’d surveyed this hill’s summit in March 2014 along with Aled Williams, when we miraculously missed incoming and threatening rain.  Although the connecting bwlch forms a part of the Y Migneint it is relatively easily accessed from the B4407 which winds its way between Ffestiniog and Ysbyty Ifan across the moor to its north-west.

Carnedd Iago (SH 782 406)

I parked next to Ffynnon Eidda; which is a well positioned beside the road.  This is on an old drover’s route and the well would have provided water for travellers and their animals.  To its north-west and rising above the B road as a grassed moorland hill is Graig Goch, its eastern aspect shields its western crags, which stretch northward giving the hill a dramatic feel when on its upper ridge.  However, for today it was the opposing land to the east where I headed.

Prior to my visit I had examined this land from the convenience of a Google car on my laptop, and all except for confirming the parking place close to Ffynnon Eidda this digitised trip did not give much away as the driver ventured to these parts on a particularly misty day. However, I did note a ten figure grid reference where contour interpolation places the bwlch and that the easiest access to this point would be to walk back up the road to where a sign signifies the county boundary; from here I would have to dive in to the morass of moor.  Once my car was parked I decided otherwise and headed in to the morass of the Y Migneint almost immediately, partly as it looked so inviting but also from this direction of approach I wanted to examine the valley to valley traverse further north from where interpolation places the critical point of the bwlch.

The bwlch of Carnedd Iago

As I headed down to the lower moor, Arenig Fawr and Arenig Fach rose above the distant surrounds, floating skyward with a foreground of breeze blown wild moor grass and bog, they looked a wonderful site.  I soon confirmed that the continuation of the valley to valley traverse headed downward from where my interpolated position placed the critical point of this bwlch.  This now meant a steady plod trough reed grass, heather and bog to where the bwlch lay.

Looking across the Y Migneint toward Arenig Fach and Arenig Fawr

The bwlch of Cranedd Iago consists of a number of uninviting peat laden channels, all of which today oozed black slime.  It was relatively easy to pinpoint where the approximate position of the critical point lay as one of the peat channels conveniently oozed its way upward toward a green slimed bog.  Nearing the bog the channel diverged in to two thinner, but still noticeable routes, each led to the green bog that then slithered downhill in to copious amounts of reed grass signifying the start of the opposing stream valley.

The green slimed bog

I spent a number of minutes wandering in the ooze jumping from one tussock laden patch of moor grass and heather to the next; always thankful that I had donned wellies and not walking boots, which for such a task would by now be immersed in wet slime.  I eventually chose the spot that I judged to be the critical point and as the Trimble beeped away gathering its allotted data I stood back and marvelled at such a place as this, one that few people must visit, and yet one that portrays the wild elements of our beautiful uplands.

Gathering data at the bwlch area of Carnedd Iago

Once six minutes of data were gathered and stored I scampered back to the equipment through the bog, closed it down, packed it away and took a much easier, direct route to the B road for a slow plod back to my awaiting car.  I’d spent just under an hour in the splendour of the bog and enjoyed every minute of it!


Postscript:

Since surveying this bwlch full LIDAR coverage is now available.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height and positional data that is now freely available for England and Wales.  Consequently the numerical details for this point have been analysed using this technique, resulting in the height and position ascertained from LIDAR analysis being prioritised in favour of that produced by the Trimble, the latter placement was approximately 16 metres from where LIDAR gives the critical bwlch to be placed; not bad considering the territory!       




Survey Result:


Carnedd Iago

Summit Height:  538.0m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Summit Grid Reference:  SH 78271 40653 (from previous Trimble GeoXH 6000 survey)

Bwlch Height:  463.85m (LIDAR)

Bwlch Grid Reference:  SH 76016 43204 (LIDAR)

Drop:  74.15m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

Dominance:  13.78% (Trimble GeoXH 6000 summit and LIDAR bwlch)


  








Monday, 3 March 2014

Mapping Mountains – Trimble Surveys – Arenig Fach


01.03.14  Carnedd Iago (SH 782 406) and Llechwedd Deiliog (SH 785 398)

Carnedd Iago (SH 782 406)

After visiting the two hills of Y Garn and Pt. 477m (SH 758 375 and SH 758 378) Aled and I drove to the junction of the B4391 and proceeded toward Ffestiniog, where we parked next to the forest boundary at SH 788 395.  Parking can be found either on the northern side of this road where a forest track enters the conifer plantation or on the southern side where there is a relatively large graveled area.

We wanted to visit Carnedd Iago (SH 783 406) which has a 538m spot height at the summit on the Ordnance Survey 1:50,000 map, and the 502m summit of Llechwedd Deiliog (SH 785 398) which looked as if it may require a little tree bashing to get to its highest point.

It was spotting with rain when we set off and the sky didn’t look very promising for the remainder of the walk.  At least by keeping to the forest track we were a little sheltered.

Carnedd Iago is situated in the expanse of Y Migneint between Arenig Fach (SH 820 415) to its east and Cerrig y Ieirch (SH 758 425) to its north-west.  It really is a lonely and forgotten spot; if not for the nearness of the B road it would also be relatively remote for a hill in Wales.

We soon came to the small clearing in the trees where access to the open hill side can be found.  From here it’s a few minutes uphill to the highest point of Carnedd Iago.  As we approached the top the views opened up, we could see that the greyness that was playing with the coastal hills to the west had escaped and was now rapidly taking over the inland hills to our east.  However, the threatened rain was miraculously being kept at bay. 


Approaching the summit of Carnedd Iago

As we picked what we thought to be the highest point for the Trimble to gather 12 minutes of data, the hill ridges to the west were trying to emerge from their dark grey enshroudment.  Sometimes when the weather is turning inclement the cloud conditions can give sudden glimpses of accentuated ridges that otherwise may be taken for granted.

The Trimble GeoXH 6000 gathering data at the summit of Carnedd Iago

Looking toward the Moelwynion

Away to the north-east one building stood out amongst the loneliness of desolate moor – Cefngarw.  We’d visited this old farm house toward the end of December 2013 on our way to the summit of Bryn Mawr (SH 801 442).

Lonely Cefngarw

Toward the west the Rhinogydd looked at their impressive best, tinged in a primeval dullness with dark cloud empathising their roughness.  All highlighted with the smallest flash of light on cloud.  The mountains are quite magical whatever the time or weather, they never seem to disappoint.

The Rhinogydd looking grey and inviting

Rhinog Fach (L) and Rhinog Fawr (R)

Once the Trimble was packed away we headed down beside the forest edge to the bwlch that connects with Llechwedd Deiliog.  Our plan was to survey the bwlch and if the forestry permitted; also its summit.  As Aled stood beside the fence I ventured in to the land of the bwlch, which not surprisingly consisted of a bog.  The more I squashed my way around its domain the more methane gas was released, this was foul spelling.

A foul spelling bog is not the best to crawl around on your hands and knees trying to estimated where the hill to hill traverse meets the valley to valley traverse.  After a particularly unpleasant few minutes I picked a spot for Trimble placement with Aled verifying that this looked the best point, and set the Trimble on the ground to gather its customary data.

The Trimble GeoXH 6000 gathering data at the bwlch of Llechwedd Deiliog

The only place left to survey was the summit of Llechwedd Deiliog.  This is immersed in a conifer plantation which I had previously visited in May 2004 when conducting a basic leveling survey.  We pottered around in the forestry and having no clear sight from one possible high point to another, we eventually had to opt for a point to survey and found one that at least in its immediate vicinity looked to be the highest.  However, it was anyone's guess whether higher ground existed to our south.

Having set the Trimble up connected to its 2m pole we waited for nine minutes of data to be collected, then switched it off, packed the equipment away and headed back through to the trees to the forest track and the awaiting car below.  It proved an excellent couple of hours on the hill.

LIDAR image of Llechwedd Deiliog (SH 785 398)

Postscript:

Since surveying these hills full LIDAR coverage is now available.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height and positional data that is now freely available for England and Wales.  Consequently the numerical details for these hills have been analysed using this technique, and where appropriate these results appear below. 



Survey Result


Carnedd Iago

Summit Height:  538.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 78271 40653 (Trimble GeoXH 6000)

Bwlch Height:  463.85m (LIDAR)

Bwlch Grid Reference:  SH 76016 43204 (LIDAR)

Drop:  74.15m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  13.78% (Trimble GeoXH 6000 summit and LIDAR bwlch)




Llechwedd Deiliog

Summit Height:  501.7m (LIDAR)

Summit Grid Reference:  SH 78522 39815 (LIDAR)

Bwlch Height:  481.2m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 78298 40196 (Trimble GeoXH 6000)

Drop:  20.6m (LIDAR summit and Trimble GeoXH 6000 bwlch) (500m Sub-Twmpau addition)

Dominance:  4.10% (LIDAR summit and Trimble GeoXH 6000 bwlch)