Mapping Mountains – Trimble Surveys – Moel y Gamelin

20.09.21  Pt. 212.2m (SJ 304 530) 

The summit field of Pt. 212.2m (SJ 304 530)

After visiting Bryn y Gaer (SJ 313 574) and Windy Hill (SJ 307 548) I navigated my way on to the B5101 road and with map in left hand and steering wheel in right, miraculously chose the right roads to turn on to and found my way driving up a narrow seemingly seldom used lane with overgrown hedgerows scraping the sides of my car.  Cresting the upper part of the lane brought me to houses, where I asked permission to pull my car adjacent to the side of someone’s front gardened wall.  With permission granted I headed for the hill. 

When I say headed for the hill, all this entailed was walking back a few metres up the lane to where a slight gap emerged in the hedge on my right, this would give access to the upper field where the summit of the hill was positioned. 

The gap in the hedge proved fun; it had two strands of floppy barbed wire across it and was relatively narrow, with the hedge consisting of thorns.  I straddled the barbed wire and delicately picked my way through the hedge with a tug and a pull and eventually emerged on a closely cropped grassy field, which online logs indicate is used as a paddock.  When driving toward the narrow lane I noticed a number of horses on the lower part of the field, when on its summit they thankfully remained out of sight. 

It was only a short walk from where I had emerged on to the field to the summit.  When approaching it I assessed the lay of land and zeroed in on what looked to be the high point, when there I put my rucksack down to mark the position.  I then assessed this point from a number of directions and decided to take two data sets, each a few metres apart. 

Having set the Trimble up for its first summit data set I walked back toward the hedge a safe distance away from the equipment, so as not to disturb satellite reception, and waited for the allotted data to be gathered and stored. 

Gathering data at the summit of Pt. 212.2m (SJ 304 530)

After closing the equipment down I repositioned it on the second position I judged to be a contender as high point for this hill and again stood back as the Trimble gathered data.  During data collection I looked west and tried to distinguish where my next hill; Middle Field (SJ 282 533) was positioned.  Since my Ordnance Survey 1:25,000 Explorer map was published there has been redevelopment in this area with a number of new houses and accompanying road networks and therefore trying to pinpoint my next hill in relation to these was not ideal as they did not appear on my map! 

The Trimble set-up position at the summit of Pt. 212.2m (SJ 304 530)

Prior to visiting this hill I had looked at LIDAR, the summit is not yet covered but the bwlch is and having produced an accurate height and position for this, it can now be combined with the result produced by the Trimble GeoXH 6000 survey to give an accurate drop for this hill. 

LIDAR bwlch image of Pt. 212.2m (summit at SJ 304 530)

Once the second data set was safely gathered and stored I closed the equipment down and headed back to the narrow gap in the hedge.  Before attempting my exit I took my rucksack off and put it through the small gap, this at least gave me a semblance of dignity as I struggled through and over the boundary hedge and barbed wire.  Once through the hedge and back on the lane it was only a short walk to my car. 

 

Survey Result: 

 

Pt. 212.2m (significant name change)

Summit Height:  212.2m (converted to OSGM15, Trimble GeoXH 6000) (the same 212.191m height produced by the two Trimble GeoXH 6000 surveys)

Summit Grid Reference:  SJ 30413 53067 & SJ 30417 53061 (Trimble GeoXH 6000) (summit relocation confirmed)

Bwlch Height:  176.9m (LIDAR)

Bwlch Grid Reference:  SJ 29817 53587 (LIDAR)

Drop:  35.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  16.65% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet