Tuesday, 31 August 2021

Mapping Mountains – Trimble Surveys – Carnedd Wen

 

02.07.21  Quarry Field (SJ 183 147) 

Quarry Field (SJ 183 147)

Prior to visiting this hill I had analysed its numerical data via LIDAR and confirmed it as a P20 Sub-Twmpau.  I had also looked at its uppermost enclosed field on the Tithe map for an appropriate name to use for that of the hill.  This walk also fitted nicely in to a circuit of five hills I could visit during the morning as due to afternoon commitments I needed to be home by 1.00pm.

LIDAR image of Quarry Field (SJ 183 147)

By the time I parked close to Cil Bach farm, under a convenient large tree giving a shaded spot to leave my car, the heat of the morning was increasing and with a forecast of possible late afternoon showers and thunder, I was glad of the excuse of those afternoon commitments and to get home before any heavy rain materialised. 

At the time of the Tithe the upper field of this hill was named Cae Bryn (no doubt documented by an English scribe as it is written as Cae Brin).  This would be an appropriate name to use for this small heighted hill, but as ever; if I could find the local farmer I was sure this name would either be confirmed or a current name given. 

Leaving my car I walked the short distance up the narrow lane to where a track veered left, following this gave access to the upper field which was planted with wheat.  I noticed this when driving toward the hill as its upper section shimmered in the light against a slight breeze.  Wheat fields are a delight to encounter; usually they have good vehicle tracks leading across them, and thankfully near to where I emerged next to the field a vehicle track headed up cresting the upper part of the hill close to its high point. 

As I walked up the vehicle track leading through the wheat I noticed Cwm Farm below.  I was in view of this farm, therefore did not want to linger at the summit however delightful wheat fields can be. 

Once near the high point I zeroed in to the summit position using the Trimble as a hand-help GPS unit with the ten figure grid reference produced via LIDAR leading me to the high point.  Once at the summit I set the Trimble up on top of my rucksack, which gives it elevation above its immediate surrounds and acts as an improvised tripod.  I quickly measured the offset between its internal antenna and the ground at its base and waited for the 0.1m accuracy level to be attained before data should be logged.  Once this appeared on the equipment’s screen I pressed ‘Log’ and walked the short distance back to the vehicle track. 

During data collection I sat on one of the tracks submerged beside the wheat.  I’d done something similar on previous occasions whilst surveying; these have usually been at bylchau, it doesn’t happen very often at a summit.  Whenever it does, be it summit or bwlch, it always brings a smile to my face as it is an unusual place to find oneself; sitting submerged in a field full of maturing crops.  This is not something that I imagine happens to many people and especially when one considers the purpose of the situation, but purpose and situation sometimes dictate and today that is exactly what happened. 

My view whilst waiting for the Trimble to gather data

Time out during data collection!

Considering its position the Trimble attained its 0.1m accuracy level remarkably quickly and gathered its five minutes of allotted data without any complaint, as sometimes when satellite reception is not good it squeals in anger and frustration! 

Gathering data at the summit of Quarry Field 

Once five minutes of data were gathered and stored I closed the equipment down, took a few photographs and packed it away.  Turning away from the summit I headed down the vehicle track amongst the wheat, thinking that a few minutes later I would be back at my car.  However, soon after leaving the summit a farm vehicle came chugging its way up the near gravelled track, and by the time I was out of the wheat it was making its way toward me.  My luck was certainly in as it was the local farmer; Richard Morris from Cil Farm. 

I talked with Richard for 15 minutes or so, it turned out that he used to go to school with my old boss and was friends with another ex-work colleague who lived in Meifod.  He also knew other friends I have from the village. 

Richard explained that he grew up in this community and farmed all his life, but only took over this field three years ago.  He knew the upper field as the Quarry Field after the disused small quarry near-by.  I mentioned the name Cae Bryn to him, which he had never heard.  I explained where I had been and the hills visited, and he then told me that he is also the local farmer for my previously visited hill, which is positioned at SJ 171 137, he told me its name is Dol Gron. 

Richard Morris of Cil Farm

When back home I checked the Ordnance Survey series of Six-Inch maps and there under the hill positioned at SJ 171 137 is an old house named Ddol-gron, with the near wood also named as Coed Ddol-gron.  Dol Gron is translated in to English as the Round or Rounded Meadow, an apt description of the hill and especially so for its upper section. 

Thanking Richard for his time I waited for him to continue down the gravelled track before I followed on foot.  I was back at my car at just before 10.50am, the walk and survey and meeting Richard had taken 50 minutes and proved very enjoyable and importantly gave names for the last two hills I had visited.  Only one hill remained for my morning’s little hill foray; this was Y Gaer (SJ 204 155) which I wanted to re-survey as during my previous visit the Trimble was placed on top of the earthen section of a covered reservoir and as this is a relatively recent man-made construct it should not be included in the height of a hill, therefore I now wanted to gather data from natural ground at its base.

 

Survey Result: 

 

Quarry Field (significant name change)

Summit Height:  109.5m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 18332 14741 (Trimble GeoXH 6000) 

Bwlch Height:  86.6m (LIDAR)

Bwlch Grid Reference:  SJ 18549 14551 (LIDAR)

Drop:  22.9m (Trimble GeoXH 6000 summit and LIDAR bwlch) (100m Sub-Twmpau addition)

Dominance: 20.89% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

 

 

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