Mapping Mountains – Trimble Surveys – Cilfaesty

14.07.21  Top Field (SO 110 879) 

Top Field (SO 110 879)

When planning the day’s outing I initially did not include this hill, mainly as it is not classified as a P30, but instead a sub, a P20.  The former are collected by the avid hill bagger, at an alarming rate for many, whilst the latter are almost an afterthought, visited by the dedicated few.  However, many P20s are excellent hills in their own right, and being a person who rarely thinks detrimental thoughts about any hill, I try and visit those hills that are classified as P20s when times allow. 

This hill is situated just southward of the previous hill I had visited and was the sixth of seven hills visited and surveyed during the day.  The day had started just after 6.30am on a quiet and tranquil hill known as Pen y Gelli (SO 180 909) and continued to Bryn Pant y Drain (SO 178 885), before visiting the summit of Pen Aran Hill (SO 137 888) and then Cold Weston (SO 141 907).  The fifth hill is another whose uppermost field is known as Top Field (SO 114 890) and it was only a short drive farther south on the same hill ridge and narrow lane until I found a good parking place just below the upper field where the summit of the second Top Field is situated. 

I contemplated heading straight up the field from an adjacent gate, but as this was in full view of a near house, I decided to walk up the lane away from the summit and by doing so I was soon in the adjacent field and doubling back toward the summit of Top Field.  Between me and it was a fence and a little lower an access gate, I opted to loose height to use the gate.  The upper field of Top Field was strewn with thistles interspersed amongst yellowish grass which added colour to the scene. 

Nearing the summit of Top Field

I had LIDARed this hill for its summit and bwlch height and position and when nearing the high point I used the Trimble as a hand-help device to zero in to the summit position compared to the co-ordinates produced from LIDAR analysis.  However, the summit would not be difficult to pinpoint by just using one’s eye. 

LIDAR image of Top Field (SO 110 879)

When at the summit I positioned the Trimble atop my rucksack, took a measurement offset between its internal antenna and the ground at its base, waited for the 0.1m accuracy level to be attained before data should be logged, and once this figure appeared on the screen I pressed ‘Log’ and scampered away so I was below the equipment and therefore not obstructing it from a clear view of those all-important orbiting satellites. 

Gathering data at the summit of Top Field

The Trimble GeoXH 6000 set-up position at the summit of Top Field

Once the allotted five minutes of data were gathered and stored I closed the equipment down, took a few photographs and packed it away.  Having done what I wanted to do I opted for the easier and direct route back to my car and quietly sauntered down the field to the access gate which was close to where I had parked.  Just one hill remained to visit for my seven hills of the day; Trehafren Hill (SO 100 910) which is positioned above a housing estate in Newtown. 

 

Survey Result: 

 

Top Field (significant name change)

Summit Height:  373.8m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision)

Summit Grid Reference:  SO 11015 87958 (Trimble GeoXH 6000)  

Bwlch Height:  346.1m (LIDAR)

Bwlch Grid Reference:  SO 11279 88639 (LIDAR)

Drop:  27.7m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  7.42% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet