Mapping Mountains – Trimble Surveys – Mynydd Twr

30.12.14  Ynys Llanddwyn (SH 388 629)   

Ynys Llanddwyn (SH 388 629)

Ynys Llanddwyn is an island positioned toward the south-western tip of Ynys Môn (Anglesey) and is connected to the main island by a spit of sand in all but high tide conditions.  It holds a special place in my memory as visiting the island was the last walk I ever did with my Mum.

On my last visit we had parked close to a toll gate (SH 414 619) and devised an extended circular walk through Newborough Forest to the far end of Ynys Llanddwyn and then back on the sands.  Today I visited with Bryn; my brother, and as he has accumulated over 20 ambulance journeys involving a multitude of motorcycle accidents that culminated in two new hips by the time he was 50, we decided to park as far into the forest as we could.

When we drove through the forest down the road to the toll gate it was open, giving free entrance for the day.  Although not marked on the map the road continues as paved until the last large car park is reached at SH 405 634.

We didn’t have any ambitions of investigating the island as Bryn had said that his knee would probably give up if we did, so our walk was aimed at reaching the spit of sand connecting the island to Ynys Môn.  This at least would give me an opportunity to accustom the Trimble with a survey on sand, which would be fun.

Leading from the car park are a number of paths, all heading either into the forest or out onto the sands, we chose a boarded section that swung around into the forest and gave views toward Ynys Llanddwyn.

The boarded section gives access onto one of a number of forest walks

The boarded section led onto a forest track which ran parallel with the sands.  As we left the track for the sands the brightness of the sun against the sand and forest gave a Mediterranean feel to the surroundings, which for Wales is an unusual occurrence.

Heading onto the sands

Arriving on the sands with the elongated shape of Ynys Llanddwyn heading out to sea with the high peaks of Eryri as backdrop to our south-east was a marvellous sight.

As Bryn continued on the sands toward a series of steps which we had spotted on the eastern fringe of the island, I set about trying to determine where the Trimble should be set up on its connecting bwlch which is named Gwddw Llanddwyn.

Bryn heads toward the island whilst I try and get to grips with assessing where the critical bwlch lay

I had imagined assessing the lay of the land at this point would be relatively easy, but as we had timed our visit for low tide, the sea was out and had left rippled contortions on the sand with a rock pool and a few other places that could be the position of the critical bwlch.  Visiting just after high tide would be a better option for gathering data at the bwlch as its position would be easier to determine.

As I chose my spot and set the Trimble up I stood back and re-assessed the ground, during this I noticed that Bryn had reached the first high point above the steps and was watching the proceedings on the beach.  As I switched the Trimble off after its allocated five minutes of data gathering I looked back up and he had disappeared beyond the first high point, I smiled with the realisation that he had pressed on into the island which would mean that I would probably be able to get summit data as well as data from the island’s bwlch.  As I climbed the steps to where Bryn had been standing I looked down onto the sands and made a note that another data set on the beach was needed, this time a few metres south-east from where the Trimble had just been positioned.

Gathering data at the first of two bwlch set up positions

There are a number of paths on the island, the one that we were on made its way on the western fringe overlooking picturesque beaches with the lighthouse at the far end of the island as a backdrop.

The western coastline of Ynys Llanddwyn

I caught up with Bryn and we switched paths to the main central one just below what I thought to be the high point of the island; I’d visited this on my previous visit and remembered that although the Ordnance Survey map gives at least six separate continuous contours at 20m the high point is not difficult to distinguish.

As Bryn continued I walked up to the high point and looked out to the other bumps on the island, all looked lower when compared to where I was standing, I placed the Trimble on its chosen spot, set it to ‘Log’ and took a few photos.  As I was doing this Bryn disappeared into the distance toward the lighthouse which stands at the far end of Ynys Llanddwyn.

Gathering data at the high point of Ynys Llanddwyn

Once five minutes of data were collected I re-joined the path and headed toward the cross and the remains of the Church of St Dwynwen, it is this that lends its name to the island of Llanddwyn.  Dwynwen is the Welsh patron saint of lovers with her Saint’s day being celebrated on the 25^th of January.

Interpretive board giving details about Dwynwen

Toward the western tip of the island are a variety of buildings with the remains of the Church being one, there is also a neat white washed line of Pilot’ Cottages and as I approached them Cliff Basterfield came out of one.  We chatted for a number of minutes; Cliff is an Honorary Warden with the Countryside Council for Wales and had lived in the area for 30 years.

Celtic Cross

Pilots' Cottages

Cliff Basterfield - Honorary Warden with the Countryside Council for Wales

By now Bryn was heading toward what we presumed was once the old lighthouse and which is marked on the map as a ‘tower’.  This looks out over Porth Tŵr-bach (cove of the small tower), and with the lighthouse shining sturdily on the opposite of the cove and with a silver sheen highlighting the high mountains on the mainland across the sea, it was a perfect place to stop and watch the world go by.

Porth Tŵr-bach and the lighthouse at the western tip of Ynys Llanddwyn

As we headed back across the stone wall that splits Porth Tŵr-bach with Pilots’ Cove I stood and watched as one lone figure did likewise on top of a rocky bluff.  The sea forever dashed against the rocks below as the sun shone, quite a magical spot, one amongst many on this island.

Looking out to sea

We re-traced our way back up to the main central path toward the cottages and onward past the high point of the island and through a gate.  I’d bi-passed this gate when visiting the summit and was now transfixed with its carving.  I waited for direct sunlight to appear from behind the cloud and look a series of photos. 

Heading back to the central path

Beauty of carving on wood

The main path comes straight down onto the sands avoiding the steps that we had used on our inward journey, and as Bryn headed off into the distance I chose another spot on the sands for a second bwlch positional survey.

Bryn (centre of photo) heading back on the sands

As the Trimble gathered another data set I watched as a number of people walked across the sands past the sheen of water cast from the lowering sun, a moment in time forever captured, quite an idyllic place.

Once the Trimble had gathered its data all that remained was to try and catch up with Bryn, but as he was now a small dot on the horizon I realised that this was futile and resigned myself to walking as quickly as I could so not to keep him waiting too long back at the car.

Gathering data at the second of two bwlch set up positions

My last memory of the beach walk consisted of a highlighted darkened image of a snow capped Mynydd Mawr, bold and big in design with Crib Nantlle extending westward toward another coastline.

Mynydd Mawr and Crib Nantlle

Ynys Llanddwyn does not disappoint, it is a popular place to visit, but one that gives, and one where solitude can easily be found.

     

LIDAR image of Ynys Llanddwyn (SH 388 629)

Since the Trimble GeoXH 6000 survey of this hill's summit was conducted, LIDAR (Light Detection and Ranging) has become available and this has revolutionised the accuracy for both height and position of hills, and it is LIDAR that is now being prioritised for this hill.

 

Survey Result:

Ynys Llanddwyn 

Summit Height:  21.8m (LIDAR)

Summit Grid Reference:  SH 38841 62953 (Trimble GeoXH 6000 and LIDAR)

Bwlch Height:  1.5m (LIDAR)

Bwlch Grid Reference:  SH 39107 63441 & SH 39099 63431 (LIDAR)

Drop:  20.3m (LIDAR) (Double Sub-Twmpau addition)  

Dominance:  93.16% (LIDAR)

For details on the 2nd visit to Ynys Llanddwyn

For further details please consult the Trimble survey spreadsheet click {here}