Mapping Mountains – Trimble Surveys – Stiperstones

25.01.14  Black Rhadley Hill (SO 342 955)

Black Rhadley Hill (SO 342 955)

Black Rhadley Hill is positioned at the southern edge of the Stiperstones ridge, the outcrops of quartzite rock so evident on the latter are not to be found on this hill, but it portrays a quiet solitude as it looks out over the River West Onny and the hills of Heath Mynd, Cefn Gunthly and farther afield; Corndon.

The OS 1:25,000 map and the enlarged Geograph map have a summit spot height of 401m, whilst the OS 1:50,000 map has 402m.  The 1:50,000 map height matches the imperial height of 1,320ft given this hill on the old OS One-Inch maps.  As both heights are close to the height of 400m to qualify for the list of The Fours, I wanted to gather accurate data and see if the hill should retain its current status.

There are few parking opportunities when approaching the hill on the narrow lane that contours around its southern flank and then gains height on its eastern side.  But a car can just be squeezed off the road close to a gate that gives access on to a good path approaching the hill from the north-east.

The sky had brightened when compared to the greyness that pervaded the land earlier in the morning.  I assessed the col when I walked over it and decided to visit the summit and gather data first.  The path led up at an easy gradient toward the summit cairn. 

Land immediately at the base of the cairn seemed higher than any other, and no doubt the land under the cairn was even higher, but I wanted good clearance for satellite reception and did not want to put the Trimble immediately against the cairn and by doing so block off half the satellite reception.  Therefore I chose a spot about a metre away and set the Trimble on the ground and waited a couple of minutes until it had attained its required 0.1m accuracy and then pressed ‘Log’.

The Trimble set-up position in relation to the summit cairn

The summit area of Black Rhadley Hill with the Stiperstones in the distance

Over the last month I’d usually gathered data for five minutes at each summit or bwlch, today I’d been extravagant and gathered a minimum of ten minutes of data at each point I’d surveyed.  This gave me time to wander down to another cairn on the southern side of the hill’s summit.  Just below this vantage point is a mature monkey puzzle tree looking rather exotic and somewhat out of place. 

The grey murk of the early morning having disappeared it left a rich clarity of colour with Heath Mynd and Cefn Gunthly being highlighted to the south.  Towards the west Corndon stood out as an elongated, almost flat topped bulk of a hill, a very different profile to the conically shaped hill I am used to seeing.  Further west a mass of cloud was gathering heralding the next front of wet weather, this could be picked out as an almost straight line across the sky, it wouldn’t be long before the thunder and hail arrived, but just for the moment everything was tranquil atop Black Rhadley Hill.

Cefn Gunthly (SO 331 948) from the summit of Black Rhadley Hill

 

Corndon (SO 305 969) from the summit of Black Rhadley Hill

Once the Trimble had gathered ten minutes of data I headed down to the hill’s connecting col.  Ahead of me the first outcrop of the Stiperstones ridge rose out of the land, a welcome site amongst rounded hills of heather.  Once at the col I chose a spot and placed the Trimble beside a vehicle track for another ten minutes of data.  From here it was no longer than a minute back to the awaiting car.  All that was left was to investigate the critical col for Heath Mynd before the massed bulk of rain and hail arrived.

The col is positioned this side of the silver car with the rock outcrops of the Stiperstones ridge in the background

LIDAR image of Black Rhadley Hill (SO 342 955)

Postscript:

Since the survey of this hill full LIDAR coverage is now available.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height and positional data that is now freely available for England and Wales.  Consequently the numerical details for this hill has been analysed using this technique, resulting in the LIDAR height and position for the col of this hill being prioritised over that produced by the Trimble GeoXH 6000.

Survey Result:

Black Rhadley Hill

Summit Height:  402.2m  (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 34263 95594 (Trimble GeoXH 6000)

Col Height:  347.7m (LIDAR)

Col Grid Reference:  SO 34656 96003 (LIDAR)

Drop:  54.5m (Trimble GeoXH 6000 summit and LIDAR col)

Dominance:  13.55% (Trimble GeoXH 6000 summit and LIDAR col)

For further details please consult the Trimble survey spreadsheet click {here}