29.08.20 Corndon (SO 305 969) and Lan Fawr (SO 297 967, previously Trimbled)
Triangulation pillars
have adorned the tops of our hills for many years. They were used for triangulating heights, however
with their function complete they are now redundant, as photogrammetry and the
use of GNSS have superseded in taking further height values.
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| Corndon (SO 305 969) |
Although their reason
for being is now redundant, they act as beacons signifying the summit of many a
hill, which can be a welcome sight after a prolonged ascent. As they are now redundant some are showing
the ravages of time after facing years of battering winds and freezing
temperatures. However, there are a
select few who venture out to help maintain trig pillars, and today I was
invited by Alex Cameron to join him, Adrian Dust and Tony Jenkins to re-paint
the triangulation pillar on top of Corndon; one of my local hills.
We met just to the
north-west of the summit where a track leaves the narrow road and heads up
toward the bwlch between Corndon and Lan Fawr; one of the outlying P30s
adjoined to this compact group of hills.
Knowing that Alex, Dusty
and Tony would no doubt catch me up, I set off a few minutes ahead of
them. Leaving the track for open steep
hillside I plodded up as the view to the west ever opened up, with Cadair
Idris, the Aran and the Y Berwyn all lined up on the horizon. Soon the intrepid painters caught me up and I
followed behind them for the remaining distance to the summit.
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| The view to the west as I'm quickly caught up |
Once at the top Alex
cleaned the trig pillar with a wire brush and then set about the paint
job. Whilst the first coat was applied I
set the Trimble up aligned with the high point of the hill, which is a small
protruding rock a few metres from the base of a large cairn and also the trig
pillar.
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| Starting the process of re-painting the trig pillar |
I’d previously surveyed
the summit of Corndon in March 2015, but the opportunity to do so again was not
to be missed, especially as we would be on the summit for around an hour. Therefore, the Trimble could be set-up
gathering data for as long as we were there.
Such a length of time is a rarity for my surveys as usually five minutes
of data is gathered.
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| The Trimble GeoXH 6000 gathering data during the first summit survey of Corndon |
By now the trig was looking extremely smart in its new whiter coat of paint, with two sides of the four complete with their first coat. During the painting and gathering data process a number of people from various directions approached the summit. A few asked whether we were employed by Ordnance Survey, one enquired about the Trimble, but the majority hunkered down with their sandwiches out of the brisk northern wind which chilled proceedings.
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| Starting on the last two sides of the trig |
The first coat now
complete, the painters tidied up a number of patches and applied a second
coat. The trig was now looking decidedly
white and sparkled when direct sunlight hit it.
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| The finished trig pillar with (L-R) Tony Jenkins, Adrian Dust and Alex Cameron |
I closed the Trimble
down having gathered over 64 minutes of data, and all that remained were the
customary photos to be taken and a walk down the southern ridge, swinging
westward following a fence line and path to the bwlch between Corndon and Lan
Fawr. The latter is listed as a Pedwar
and as we were near it we visited its summit which gives good views back toward
its higher neighbour.
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| Lan Fawr from Corndon |
A saunter back on the
track to the awaiting cars, and push bike in Alex’s case, and a good
conversation about all things hilly when back at the cars rounded the day off very
nicely.
Survey Result:
Corndon
Summit Height: 513.6m (converted to OSGM15, average of two
Trimble GeoXH 6000 surveys)
Summit Grid Reference: SO 30599 96922
Bwlch Height: 310.5m (converted to OSGM15, from previous
Trimble GeoXH 6000 survey)
Bwlch Grid Reference: SO 32519 99517 (from previous Trimble GeoXH
6000 survey)
Drop: 203.0m
Dominance: 39.54%
Lan Fawr
Summit Height: 426.1m (converted to OSGM15, from previous
Trimble GeoXH 6000 survey)
Summit Grid Reference: SO 29711 96759 (from previous Trimble GeoXH
6000 survey)
Bwlch Height: 392.5m (converted to OSGM15, from previous
Trimble GeoXH 6000 survey)
Bwlch Grid Reference: SO 29968 96772 (from previous Trimble GeoXH
6000 survey)
Drop: 33.6m (from previous Trimble GeoXH 6000
survey)
Dominance: 7.88% (from previous Trimble GeoXH 6000
survey)
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