Tuesday, 11 May 2021

Mapping Mountains – Trimble Surveys – Carnedd Wen

 

08.03.21  Pt. 170.7m (SJ 193 018) and Lower Cil (SJ 185 016)

Pt. 170.7m (SJ 193 018)

Two weeks ago Linda, Nic and I walked on the canal towpath and visited a hill positioned above Berriew which is known locally as Llwynderw Hill.  This gave a good circular walk using the Red Lane as our way back toward our inward route on the towpath.  Today I was out with Linda and had suggested walking beyond where we had previously left the towpath, visiting two relatively small heighted hills before using the lanes and public footpaths close to the summit of Llwynderw Hill as our descent route. 

With strong winds and rain forecast mid-week the continued settled conditions were not to be missed and therefore I met Linda at 11.00am to saunter on the canal towpath, chatting away about all manner of things past the Belan Lock and onward.  The hum of traffic on the Welshpool to Newtown road slowly ebbed in to the distance with silence taking over the land.  This was only broken by our conversation and the ever present background of birdsong.  This is an accompaniment to spring’s arrival when renewed warmth filters down through the chilled months of winter.  Today the conditions were blissful, not in a dramatic sense but in one where contentedness was easily found. 

The canal towpath leading toward our first hill of the day

We stopped for lunch at a picnic table close to where we would leave the canal tow path for a narrow country lane, and once sandwiches, boiled eggs and chocolate bars had been devoured we set off up the lane toward Lower Brithdir, where a public footpath guided us over a stream beside fields full of newly born lambs suckling their mothers as their thin tails wagged this way and that. 

LIDAR image of Pt. 170.7m (SJ 193 018)

Beyond the stream we followed a rising field toward the summit of our first of two hills of the day.  Both had been LIDARed prior to our visit and although it would have been easy to determine the high point of this first hill, I nevertheless used the ten figure grid reference produced by LIDAR to zero in on its summit.  Once found I placed the Trimble on top of my rucksack, measured the offset between its internal antenna and the ground at its base and stood back as six minutes of data were collected. 

Gathering data at the summit of Pt. 170.7m (SJ 193 018)

Once the Trimble was packed away we made our way across the field and called at Cefn-yr-allt, which I hoped was a farm, it wasn’t, so any thought of finding an appropriate name for either the hill or the upper field that had just been Trimbled would have to wait for another day as the person who answered the door could not help with my enquiry. 

LIDAR image of Lower Cil (SJ 185 016)

Our second hill was relatively near and once we were walking down the access track leading to Cefn-yr-allt we looked out for the most convenient way in to the field that rose toward the top of the hill.  Our way up was via a fence beside a particularly boggy area, disturbing two ducks as we did so.  We were soon on top, with the summit crowned by a small brick enclosed water reservoir.  Once I’d chosen the spot for Trimble placement I joined Linda sitting beside the small brick wall below the Trimble and waited for the allotted data to be gathered and stored. 

Gathering data at the summit of Lower Cil

Our onward route took us down to Lower Cil Farm where we met George Pritchard.  We chatted for a number of minutes and he explained that he was the tenant having been here for 34 years, moving from the Oswestry area to farm this land.  He said that the land taking in the summit of this hill is known by the farm name; Lower Cil, a practice that is not uncommon.  George directed us through his farm yard toward the gate which led down to a stream; warning us that getting over the stream may be problematic. 

Across the fields toward the stream 

We sauntered across fields down to the stream, thankfully it proved relatively easy to cross, but the last few days had been dry, following a downpour it would no doubt be a tricky place to get over, and our onward route necessitated us being on its opposing bank. 

A chicken caravan!

Late afternoon with the Breiddin as backdrop

Rising fields soon took us to a track and then lane which brought us to Cefn-hilin; a farm we called at a couple of weeks ago after visiting the summit of Llwynderw Hill.  We now had options for our descent route; all would in time either lead us on to the Red Lane and / or back to the canal tow path.  We opted for a route taking in new ground following a descending lane through Belan and then across fields above the canal with Welshpool spread out before us with the rising Breiddin as backdrop. 

A gentle land

Dusk approaching

It proved a lovely route down, stopping and looking back as the sun sank forever lower leaving a silvered sheen in the sky as dappled clouds were highlighted pink.  I left Linda in town and slowly walked back home happy and content with the day’s outing. 

 

Survey Result: 

 

Pt. 170.7m (significant name changes)

Summit Height:  170.7m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision) 

Summit Grid Reference:  SJ 19323 01898 (Trimble GeoXH 6000) 

Bwlch Height:  132.5m (LIDAR)

Bwlch Grid Reference:  SJ 18115 01656 (LIDAR)

Drop:  38.2m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  22.40% (Trimble GeoXH 6000 summit and LIDAR bwlch)


 

 

Lower Cil (significant name change)

Summit Height:  159.3m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SJ 18556 01630 (Trimble GeoXH 6000) 

Bwlch Height:  137.8m (LIDAR)

Bwlch Grid Reference:  SJ 18939 01777 (LIDAR)

Drop:  21.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) (100m Sub-Twmapu addition)

Dominance:  13.49% (Trimble GeoXH 6000 summit and LIDAR bwlch)


 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

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