Friday 20 March 2015

Mapping Mountains – Trimble Surveys – Stiperstones



19.03.15  Corndon (SO 305 969, only bwlch surveyed), Ratlinghope Hill (SO 408 976), Cothercott Hill (SO 408 997) and Betchcott Hill (SO 421 982)   

Cothercott Hill (SO 408 997) in distance on right

Standing in a misty Shropshire field in the morning with a good splattering of mud on the ground is an esoteric pastime, but bwlch surveying throws up its own particular delights and as the quiet hum of cars lost in the morning mist disappeared off into the distance I placed the Trimble down on an earthen track that gave access from one green and pleasantly nondescript field into another.  This was the position of the critical bwlch for Corndon, which is one of my local hills.  I’d visited the summit of Corndon on a number of occasions but had never had the pleasure of visiting its bwlch.

The critical bwlch of Corndon

Once the Trimble had gathered its allotted data I packed it away and turned and smiled at the field as it ebbed into the mist of a springtime morning, and walked back to my car which was squeezed off the road adjacent to a letterbox.  As I drove further east blue skies emerged above the swirling mist, this was only a foretaste of conditions to come as by the time I’d found my parking spot the mist covered the hills I planned to visit.

The first of these was Ratlinghope Hill which is listed as a Four and is situated overlooking the Darnford Brook as it flows down through the sleepy hamlet of Ratlinghope.  I’d parked high on the minor lane as it boldly climbed east toward and over the northern confines of the Long Mynd.  As I didn’t want a lengthy climb back up hill to the car at the end of my walk I headed down the road toward the old farm of Lower Darnford.

There’s a unique beauty on the land when mist pervades, a quietness given to a linear landscape.  Today the mist was just a passing visitor as the sun would soon burn it away.  Mist can concentrate one’s mind onto the smallest detail and this morning I glimpsed a dew laden web, balanced between the squared wire of a fence with each drop pearl like, heavily laden, a moment in time ready to be edged away by the late morning’s warmth.

Dew laden web

Pearl like and heavily laden

I followed a track down past an old farm and used a footbridge made of railway sleepers to cross the upper Darnford Brook.  The lingering mist shielded me as I went off path and walked up the last remaining fields toward the summit of Ratlinghope Hill.  As I assessed the summit area trying to pinpoint the highest point the mist quickly dispersed leaving spring warmth with radiant blue of sky butting against the greens of high pasture.

Crossing the Darnford Brook

The mist starts to disappear

As the Trimble started collecting data I noticed a tractor making its way through a near open gate delivering feed for sheep, I was in full view so I wandered down to have a chat with the occupant.  Matt Stankey farms from Upper Stitt Farm, he was delivering the feed to one of his father’s fields.  We chatted for quite some time, we both knew that the hill has no right of access, but he said that he didn’t really mind me being there.

Gathering data at the summit of Ratlinghope Hill

After Matt drove off to deliver another stack of feed I gathered the Trimble and headed down to the connecting col between Ratlinghope Hill and Cothercott Hill, once this had been Trimbled I continued toward a lane that gave access onto the next hill of the day.

Time for eaties

Gathering data at one of two options for the col of Ratlinghope Hill

By now the mist had gone leaving a slight haze to distant views, but the freshness was evident with spring growth just showing itself.  The lane led northward past a number of buildings named Thresholds, a footpath then gave access onto the large, open field which makes up the upper part of Cothercott Hill.  As I approached the summit the tumulus marked on the map became evident, a cylindrical masterpiece seemingly deposited on the high point of the hill, rounded through design and erosion it nestled on its perch and waited to be Trimbled.

Gathering data at the summit of Cothercott Hill

By now my watch had stopped again, which had also happened on my last walk, therefore I continued noting the time of each data set via the clock in the Trimble, this needs to be done to download the correct Rinex Data from the Ordnance Survey website, with the data then being post-processed.  Because of this some of the allotted data collection times overshot my usual five minutes.

After the summit of Cothercott Hill had been surveyed I re-joined the high lane and continued onto a partly paved track heading south-east toward the critical col of Cothercott Hill.  As the Trimble gathered data from this spot four people walked down the track heading toward refreshment in the Bridges, we chatted for a few minutes, I quite envied their company and a beer in the afternoon sunshine and wondered if my life was now dictated by endless surveys on my own; woe is me!

The critical col of Cothercott Hill

Only one summit remained to survey and that was Betchcott Hill which is listed as a 400m Sub-Four with 20m of drop.  I placed the Trimble adjacent to a fence on the high point of the hill and patiently waited for it to attain its 0.1m accuracy before data can be logged.  Once complete I sauntered over to the near trig, gathered another data set from the highest ground beside it and waved ‘hello’ to a passing couple, soon we were chatting; James and Kate Morgan were on their way to the Bridges to stay the night before continuing the next day to Bishops Castle following part of the Shropshire Way.  They had come from Wolverhampton by train and had picked a few glorious days to do this part of the long distance footpath as the weather seemed set fine.

The summit of Betchcott Hill

James and Kate Morgan on part of the Shropshire Way

Beyond the summit of Betchcott Hill is its critical col, I took data from two points, the first on a track next to a fence, passing the time talking to four young lads taking part in their Duke of Edinburgh silver award scheme.  The second was in a reed infested bog.

All that remained was a walk down a good path that crossed the Colliersford Gutter as it flowed down past fern, bracken and grazing sheep before a small climb uphill to the awaiting car.  It had been another excellent day on the hill with the Shropshire hills proving a delight, as new ground visited usually does. 

LIDAR image of Betchcott Hill (SO 421 982)

Postscript:

Since the survey of these hills 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 these hills have been analysed using this technique, resulting in the LIDAR height and position for some of these hills being prioritised over that produced by the Trimble GeoXH 6000.



Survey Result:


Corndon

Summit Height:  513.6m (converted to OSGM15, average of two subsequent Trimble GeoXH 6000 surveys)

Summit Grid Reference:  SO 30599 96922 (from subsequent Trimble GeoXH 6000 surveys)

Bwlch Height:  310.5m (converted to OSGM15)

Bwlch Grid Reference:  SO 32519 99517

Drop:  203.0m

Dominance:  39.54%





Ratlinghope Hill

Summit Height:  411.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 40834 97625 (Trimble GeoXH 6000)

Col Height:  367.4m (LIDAR)

Col Grid Reference:  SO 40696 98345 (LIDAR)

Drop:  44.2m (Trimble GeoXH 6000 summit and LIDAR col)

Dominance:  10.73% (Trimble GeoXH 6000 summit and LIDAR col)





Cothercott Hill

Summit Height:  443.8m (converted to OSGM15)

Summit Grid Reference:  SO 40837 99725

Col Height:  387.9m (converted to OSGM15)

Col Grid Reference:  SO 42032 98546

Drop:  55.8m

Dominance:  12.58%





Betchcott Hill

Summit Height:  414.2m (LIDAR)

Summit Grid Reference:  SO 42106 98231 (LIDAR) (summit relocation)

Col Height:  394.3m (LIDAR)

Col Grid Reference:  SO 42922 97926 (LIDAR)

Drop:  20.0m (LIDAR) 

Dominance:  4.82% (LIDAR)
  
    

  


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


  


No comments: