Mapping Mountains – Trimble Surveys – Stiperstones

20.03.17  Cefn Digoll (SJ 275 084)

The northern section of Cefn Digoll (SJ 275 084)

My mother once told me that when she married and moved to Welshpool one of the first things my father did was point toward the hill to the east of the town and say ‘that is the Long Mountain’.  This hill dominates the view to the east and forms a natural barrier that over the years has been exploited as a boundary between the Welsh and English, with the modern border running on the eastward side of the broad summit ridge.  The hill is known in Welsh as Cefn Digoll, which can be translated in to English as the unbroken mountain.  The high point is known as the Beacon Ring or Caer Digoll in Welsh and has mixed woodland submerging its triangulation pillar, with the remains of an impressive Iron Age earthen embankment encircling the summit area.

Although the high point of Cefn Digoll is well known and visited by many people each year, the extended hill also has another prominent summit towards its north, this latter summit is almost forgotten but affords good views and quiet surrounds.  However, its high point is not on open access land so permission to visit should be sought.

This northern summit of Cefn Digoll is one of the closest P30 hills to where I live, and yet up until today I had never visited.  The morning’s rain persisted until early afternoon with damp grey sky slowly ebbing to the first sign of blue as I joined Ed in the Royal Oak for an hour’s catch up over coffee.  Once back home I decided to head out and quickly packed all necessary gear. 

The broad summit ridge of Cefn Digoll has a minor lane running from south to north which affords a high starting point if so wished.  I parked in a mud strewn lay-by close to the paved access lane to the Longmountain Farm.  Before venturing up the lane I chatted with a man who was digging a hole to erect a farm sign, he was the brother of the farmer from the Longmountain Farm and grazed some of the lower fields on the hill.  We chatted at length before I continued up the access lane toward a public footpath that heads across a couple of fields.

Ahead, the sun skimmed off the lower fields of the Severn valley which shone silver like without detail but with a friendly embrace.  I followed the footpath before heading toward the hill’s high point using gates to gain access.  Once on the summit I assessed the lay of land and chose the clump of grass I judged to be the highest, and then set the Trimble on top of my rucksack after taking a measurement offset from its internal antenna to the ground at the base of the rucksack and stood back whilst five minutes of data were gathered.

The view of the Breiddin from the summit of Cefn Digoll (SJ 275 084)

Gathering data at the summit area of Cefn Digoll (SJ 275 084)

Once I packed the Trimble away I headed toward the adjacent field where a mast rose skyward, a gate then led me in to the yard of Longmountain Farm.  I knocked on a couple of doors and spoke to the mother in law of the farmer, and just as I thanked her for her time and was about to set off back to my car a vehicle pulled up, the first words weren’t encouraging; ‘you shouldn’t be here you know, what are you doing here?’  Karen and Brian Morris were rightly questioning what I was doing wandering around in their yard; I introduced myself and explained that I’d met Brian’s brother at the end of the paved lane and that I was interested in place-name research for the Welsh hills and particularly for the high point of their hill.  We chatted for 20 minutes or so and I left with smiles and a wave goodbye.

Karen and Brian Morris of Longmountain Farm

The view of the bwlch with the Stiperstones in the background

By the time I reached the bottom of the paved lane Brian’s brother was hard at work digging out a trench to insert a water pipe having erected his farm sign, we chatted again and I asked permission to visit the adjacent field having already explained the fineries of the Trimble.  A few minutes later having assessed the land at the bwlch, the Trimble was atop my rucksack gathering its all-important data.

Gathering data at the bwlch

The bwlch consists of a large greened field with a pond like puddle close to where I judged the critical point to be placed.  As the Trimble gathered its customary five minutes of data I wandered the periphery of the pond and took in the view as the low sun cast illuminated colour on the land.

Packing the Trimble away I walked back to the gate and the minor lane toward my car.  It had been an enjoyable 1½ hours mainly spent waiting for the Trimble to gather its allotted data and chatting with local farmers, an excellent way to spend an afternoon.

LIDAR image of Cefn Digoll (SJ 275 084)

Postscript:

Since the survey of this hill 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 hill has been analysed using this technique, resulting in the LIDAR height and position for the summit of this hill prioritised over that produced by the Trimble GeoXH 6000.

Survey Result:

Cefn Digoll (significant name change)

Summit Height:  381.6m (LIDAR)

Summit Grid Reference:  SJ 27538 08462 & SJ 27541 08460 & SJ 27543 08461 (LIDAR) 

Bwlch Height:  343.1m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SJ 27824 07953 (Trimble GeoXH 6000)

Drop:  38.5m (LIDAR summit and Trimble GeoXH 6000 bwlch)

Dominance:  10.09% (LIDAR summit and Trimble GeoXH 6000 bwlch)

  

For further details please consult the Trimble Survey Spreadsheet