Tuesday 12 January 2021

Mapping Mountains – Trimble Surveys – Elenydd

 

29.09.20  Gaer Fawr (SN 649 719) 

Gaer Fawr (SN 649 719)

Misted mornings can give some of the most beautifully tranquil encounters with hills.  The forecast for the day was for dry and sunny conditions, but as I pulled up below the slopes of Gaer Fawr it was bathed in mist with wisps dancing around the near conifer plantation to the south-east. 

Misted morning

Prior to my visit I’d analysed the details for this hill via LIDAR and produced ten figure grid references for both its summit and bwlch, as well as accurate heights for each.  In many instances the Trimble only confirms what LIDAR produces, but on occasion its placement can mean a more accurate height and position. 

LIDAR image of Gaer Fawr

Leaving the car I accessed the hillside through a gate and followed a fence line as it strode steeply uphill.  Below me the mist continued in ever intricate patterns ebbing this way and that.  Above, the fence line continued across more gently rising ground where groups of sheep, horses and cattle all grazed together. 

Friendly horses

The summit of Gaer Fawr was still cloaked in mist as I gained height.  Passing the sheep who ignored me, my next encounter was with the horses, who trotted my way as friendly as can be.  Meanwhile the cattle also seemed oblivious to my presence.  I stopped and stroked a couple of the horses who instinctively edged back as my hand was held out toward them. 

LIDAR summit image of Gaer Fawr

By the time I reached the summit glimpses of blue were appearing through the mist, and although beautiful in its own right I wasn’t given any extended view from this summit on this particular day.  This didn’t matter as it was just a pleasure to be out and standing on top of the earthen ramparts that lend themselves towards the hill’s name. 

The Trimble set-up position at the summit of Gaer Fawr

The high point of Gaer Fawr is a nobble of earth on the ancient raised embankment close to a rock.  Soon the Trimble was set up aligned to this high point and beeping away gathering individual data.  During data collection I wandered down the embankment, looking back at the summit as it contoured around in a great misted sweep. 

Gathering data at the summit of Gaer Fawr

Once the allotted data were gathered and stored I closed the equipment down, packed it away and retraced my inward route back down to my car and was soon below the mist as the sun burnt it away.  Such walks are simple affairs, but still heightened by conditions and scenery. 

 

Survey Result: 

 

Gaer Fawr  

Summit Height:  282.1m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 64936 71956 (Trimble GeoXH 6000)

Bwlch Height:  187.6m (LIDAR)

Bwlch Grid Reference:  SN 64978 71574 (LIDAR)

Drop:  94.5m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  33.49% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

No comments: