Tuesday 24 March 2015

Mapping Mountains – Trimble Surveys – Stiperstones


22.03.15  Corndon (SO 305 969), Lan Fawr (SO 297 967) and Stapeley Hill (SO 313 991)   

Stapeley Hill (SO 313 991)

Corndon stands in a part of Wales that straddles the border between the old county of Montgomeryshire and that of Shropshire, when viewed on a map this border diverts from its north – south meandering route to make a land grab of this hill and takes in all its immediate surroundings.  However, the border is never that far away and today I straddled it in the same walk taking in the 500m hill of Corndon, and the two 400m summits of Lan Fawr and Stapeley Hill, the former 400m hill in Wales and the latter in England.  As I wanted to survey each connecting point I would be measuring both a bwlch and a col on the same walk, a novel way to spend a day on the hill!

I parked at the start of an earthen track beside a corner of the lane at SO 301 976 where a number of cars can be left, this is the start of the track that leads to Mitchell’s Fold Stone Circle which I planned on visiting later in the day on my way to Stapeley Hill.

Adjacent to where I parked is an option for the critical col of Stapeley Hill, the Ordnance Survey map gives a 344m spot height on the road, I found that the position of the critical col to be in the adjacent field, during the time I stood in the field near to the fence beside a hedge of hawthorn trees waiting for the Trimble to gather its allotted data, two vehicles stopped, the first was driven by the son of the farmer whose field I was mysteriously standing in, the second occupant wound the window down and asked if I was lost.  Both seemed happy enough with my explanation of what I was doing.

After packing the Trimble away I walked up the continuation of the lane for a short distance and headed on a track that bisects Corndon from Lan Fawr, I left this track adjacent to a fence that climbs up the north-western side of Corndon.  The day’s forecast was good, with high cloud breaking up toward the late morning and sunshine in the afternoon; I stopped to admire the profile of Lan Fawr before following the path beside the fence upto the summit of Corndon.

The summit area of the hill now has a wooden bench which I thought an undue addition to its trig pillar and ancient cairn; it seems man cannot stop dabbling with such places.  Having said that I was tempted to sit and admire the view once the Trimble was set up and gathering data, I didn’t, and instead I noted the details of the survey in a notebook and looked out to the border country below.

Gathering data at the summit of Corndon

When conditions are clear the hills of Cadair Idris, the Aran and Y Berwyn are lined up on the horizon, today the first glimpse of breaking cloud and slender threads of blue sky emerging with a dull ache of monochrome colour obscured these higher hills from view.

I headed down toward Lan Fawr in a southward direction following the fence that once designated the boundary of a conifer plantation that blighted this hill’s western side, in its higher part this has thankfully now been felled leaving a multitude of tree stumps that shone almost white as the sun started to emerge and burn away the high blanket of cloud.

The remains of the conifer plantation on the upper western part of Corndon

By following the fence adjacent to the conifer plantation I ended up at the critical bwlch of Lan Fawr, this has an earthen track crossing it, I chose the spot for the Trimble to be placed, gathered five minutes of data and walked up toward the summit of the hill.

Gathering data at the critical bwlch of Lan Fawr

Lan Fawr forms the western edge of the compact group of hills surrounding Corndon, it is elegant in shape and topped with an appealing small crop outcrop.  I’d visited this hill once before on a winter’s walk doing a circuit of seven P30s when frost edged the landscape.  Today the sun was now partially out, layering shadow interspersed amongst colour across the landscape.

Gathering data at the summit of Lan Fawr

Stapeley Hill (centre background) from the slopes of Lan Fawr with the distinct wooded summit of Callow to its left

As I sauntered down the track from Lan Fawr back toward my car and the continuation toward Stapeley Hill I started meeting other walkers, many heading up Corndon, all with smiles, I stopped and chatted with three people who had driven from Shrewsbury.  By the time I walked past my car and continued on the earthen track toward Mitchell’s Fold Stone Circle I was contemplating converting my trousers to shorts as the strength of the sun almost baked the land after the many months of winter’s enclosing cold.

Lan Fawr from the track that bisects this hill from that of Corndon

Before visiting the stone circle I wanted to gather data at the second option for Stapeley Hill’s critical col, this is beside the end of the earthen track where a number of cars can be parked.  As the Trimble did its stuff a multitude of people were coming and going, with cars departing and arriving in a steady flow, with many accompanied with dogs that flew away from the confines of their leads and sparked into life as only dogs can.

Gathering data at the col area of Stapeley Hill

At the end of the earthen track is a cattle grid and a choice of paths with the main one leading to Mitchell’s Fold Stone Circle.  This is of Bronze Age construction and a popular visiting spot, the circle now supports fifteen stones with as many as thirty having once been part of it.  Many are small and butt out of the ground as almost forgotten afterthoughts, however the circle is impressive, partly for its construction but also for its position as it sits in dry moorland of heath and looks out toward Stapeley Hill. 

Mitchell's Fold Stone Circle

The tallest stone is 1.91m (6ft 3 in) in height and is considered to be positioned at the south-east entrance to the circle; it is also situated close to the line of the southern moonrise.  I hadn’t visited this place for a number of years and to take it in as part of a hill walk seemed rather fitting. 

The tallest stone in the Mitchell's Fold Stone Circle

Ahead lay the shapely mass of Stapeley Hill, green paths criss-cross Stapeley Common between Mitchell’s Fold and its summit, I picked the one that looked as if it was the most suitable ‘summit path’ and headed toward the top of the southern end of the hill.  This is where the Ordnance Survey gives a small 400m ring contour, as opposed to the 403m summit height a little way north of this point.

As I reached the southern end of the hill’s summit ridge I sat in sunshine as the Trimble gathered data atop a large embedded rock that looked as if it was the high point of this part of the hill.  This was about four metres from a medium sized cairn and looked out toward the higher summit about 250 metres further north.

Gathering data at the southern top of Stapeley Hill

As I approached the higher summit a couple were already lazing in the sun with two friendly dogs running around enjoying themselves, we chatted for quite some time, I explained what I was doing and then spent a few minutes judging if an embedded rock was higher than the ground at the base of the summit cairn.  I also spent time wandering around giving the rocks at the base of the cairn a good kick, I don’t consider this vandalism as it is a necessity of surveying, and if a rock was booted hard enough to become dislodged I would always replace it.

Once the couple and their dogs departed I placed the Trimble on a large embedded rock and waited for it to attain its 0.1m accuracy before data can be logged.  It had attained this accuracy level rather quickly during the day’s previous surveys, now it decided to chug down to this point, so I waited.  During the waiting process I noticed another couple; Dave and Michelle Heap, making their way up to where I was from the hill’s southern top. 

Gathering data at the summit of Stapeley Hill

As they approached we chatted and I asked if they would mind diverting around this odd little yellow and black piece of equipment that was beeping every second as it collected another datum point as it balanced on its rock.  Dave and Michelle lived in Telford and seemed quite interested in what I was doing so we chatted away, they were walking as far as Callow (SO 324 011) which is a distinctive wooded hill top that is easily identified from miles around.  I quite envied their ridge walk, heading off in the sunshine to another hill that I had wanted to visit for many years but had still not done so, as we chatted I mentioned that I may do another walk later in the afternoon up Linley Hill, but I wondered if I’d got enough time to do it, Michelle told me about the ‘Linley Birches’ and Dave said ‘go for it’.

Dave and Michelle Heap at the summit of Stapeley Hill

Gathering data at the summit of Stapeley Hill with the distinct wooded summit of Callow in the background

By the time Dave and Michelle headed toward Callow the Trimble had collected 13 minutes of data, I packed it away and re-traced by steps back to Mitchell’s Fold Stone Circle.  I stopped and took photographs of the standing stones, all looking out on a landscape that no doubt had changed over the millennia, but although a local landmark and visited by many people during each year, the solitude and positioning of this stone circle is one of unstated grandeur.  Next stop; Linley Hill.

LIDAR image of Stapeley Hill (SO 313 991)

Postscript:

Since the survey of 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, resulting in the LIDAR height and position for some of these hills being prioritised over that produced by the Trimble GeoXH 6000.



Survey Result:


Corndon

Summit Height:  513.6m (converted to OSGM15, average of two Trimble GeoXH 6000 surveys)

Summit Grid Reference:  SO 30599 96922

Bwlch Height:  310.5m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Bwlch Grid Reference:  SO 32519 99517 (from previous Trimble GeoXH 6000 survey)

Drop:  203.0m

Dominance:  39.54%




Lan Fawr

Summit Height:  426.1m (converted to OSGM15)

Summit Grid Reference:  SO 29711 96759

Col Height:  392.5m (converted to OSGM15)

Col Grid Reference:  SO 29968 96772

Drop:  33.6m

Dominance:  7.88%




Stapeley Hill

Summit Height:  402.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 31347 99169 (Trimble GeoXH 6000)

Col Height:  341.3m (LIDAR)

Col Grid Reference:  SO 30273 98052 (LIDAR)

Drop:  61.6m (Trimble GeoXH 6000 summit and LIDAR col)

Dominance:  15.30% (Trimble GeoXH 6000 summit and LIDAR col)




For details on the bwlch survey of Corndon




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





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