Mapping Mountains – Trimble Surveys – Carnedd Wen

 

15.09.20  Top Field (SJ 070 055)  

Top Field (SJ 070 055)

This was the seventh of a planned thirteen hills that Alex and I hoped to visit during the day, with me sitting out three of these as they had recently been Trimbled.  Alex had navigated the short distance from our previous hill; Caer Wedyn (SJ 095 047) on the narrow lanes that pre-dominate much of the land hereabouts, and I parked in a passing place close to the entrance track to the old farm of Rhiw-hiriaeth-uchaf after Alex had removed a large tangled tree branch that was lodged in the soon to be parking place. 

It was only a short walk on the narrow lane to the access track that swept up the northern flank of the hill toward the old farm which was tucked away out of sight under the summit to the south. 

Alex heading up the start of the access track toward the summit of Top Field

Prior to our visit I’d examined LIDAR and produced data for this hill’s summit and bwlch, and now with the grid co-ordinates produced by LIDAR analysis we zeroed in on the high point.  This consists of grass and as I set the Trimble up a small herd of cows slowly headed our way. 

LIDAR image of Top Field

After asking Alex if he could usher the cows a safe distance from the survey equipment I waited for the Trimble to achieve the 0.1m accuracy level before data should be logged, and once this appeared on the screen I pressed ‘Log’ and retreated to join Alex who was sitting admiring the view. 

With the cows a safe distance away the Trimble could start gathering data

Gathering data at the summit of Top Field

Away to our north Moel Bentyrch dominated the view with its greyed scree and crags on fine display, with the distant outline of ridges and summits beyond.  However, to our west a grey murk had appeared that forever crept nearer.  This looked like cloud bearing rain which was surprising as rain was not forecast. 

Moel Bentyrch

Once the Trimble had gathered and stored its allotted data we headed toward the access track leading to the farm.  From this viewpoint it looked as if the farm required quite a distance to walk, therefore we headed back with intention to use the track back toward the car. 

On our way Alex noticed a vegetated knoll above a small quarry and as this looked a similar height to the point that had just been Trimbled, we headed toward it.  Arriving at the knoll we both thought it probably consisted of debris from the quarry, but as we were now there we decided to gather data. 

Gathering data at the top of the knoll

The farm was now directly below us and as the Trimble beeped away gathering individual data I headed down the continuation of the field to see if I could access it from this direction.  I couldn’t due to wired fences and therefore made my way back to join Alex. 

Once the Trimble was packed away I decided to walk down the track to the farm to make place-name enquiries whilst Alex headed back to the car to get a brew on.  Having knocked at the front door of the old farm and getting no reply I slowly made my way back up the track and decided to get a third data set from where we both considered the highest part of natural ground was positioned at the base of the small vegetated knoll. 

Gathering data at the base of the knoll

After the third data set was taken I sauntered back over the hill and joined the access track and headed down to the narrow lane and the car where Alex duly gave me a welcome large cup of tea. 

Getting the brew on

We stood and chatted whilst sipping on tea and tucking in to the variety of food on offer which included Alex’ Mum’s bara brith and an assortment of crisps, boiled eggs, sandwiches and bananas. 

During our lunch break a tractor appeared chugging up the lane, once it safely negotiated the narrow gap between the paved section of road and my car I flagged it down.  The person driving the tractor was the local farmer; Owen Evans and he told me that unsurprisingly the hill has no individual name, but the field where the summit of the hill is situated is known as Top Field. 

Owen Evans

The day was proving productive with lots of hills being visited and chance encounters with farmers.  The summit of our next hill was beside a track leading to a farm.  I wanted to visit this farm to make place-name enquiries as I’d passed this way a few weeks before and due to the oppressive heat I decided to press on rather than face the re-ascent of the steep track leading down to the farm house. 

 

Survey Result: 

 

Top Field (significant name change)  

Summit Height:  333.3m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 07082 05572 (Trimble GeoXH 6000) (summit relocation confirmed)

Bwlch Height:  301.1m (LIDAR)

Bwlch Grid Reference:  SJ 06237 05273 (LIDAR)

Drop:  32.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) (Sub-Trichant reclassified to Trichant)

Dominance:  9.65% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet