Thursday, 11 June 2015

Mapping Mountains – Trimble Surveys – Cairngorms

27.05.15  Meall Gaineimh (NJ 166 051)    

Meall Gaineimh (NJ 166 051)

The Cairngorns are renowned as being some of the most committing hills in Britain with a high plateaued area comprising many of the highest mountains in the land.  Although I had seen these hills before, albeit from a afar, this would be my first visit to their inner depths.

Our main purpose for visiting was to survey Meall Gaineimh which is positioned at the end of the north-easterly ridge that continues from Ben Avon down toward the Builg Burn and River Avon.

This survey had been arranged for Iain Robertson who is the instigator behind the heightings programme undertaken by The Munro Society (TMS).  It was this programme that initiated independent absolute height surveys in Britain using Differential GPS equipment; it was also this programme that initiated the surveys of Sgurr nan Ceannaichean and Beinn a’Chlaidheimh, resulting in the Scottish Mountaineering Club (SMC) reclassifying each from Munro to Corbett status.  This heightings programme has now ended, but as a sign of our appreciation toward Iain and TMS we offered a survey of their choice, the hill decided upon was Meall Gaineimh.

The reason for choosing Meall Gaineimh is that it has a 912m spot height beside the cairn on its summit area, however Jim Bloomer had previously assessed this area with an Abney Level and concluded that the granite tor which is positioned approximately 100 metres from the cairn, is at least 2m higher than the ground beside the cairn, meaning that if the spot height is accurate the hill is close to the 914.4m / 3,000ft benchmark height for it to be considered by the SMC for Munro Top status.

We met at the parking area below Corgarff Castle to the east of the hill, having overnighted at the Smugglers Hostel in Tomintoul, which is highly recommended for a base to investigate the eastern part of the Cairngorms.  John had been given permission for us to drive as far as Inchmore by the Balmoral Estate which reduced our walk from 18 to 12 miles.  This was important as we carried all necessary surveying gear with us and the weather forecast from mid-afternoon on was not conducive for surveying, with a low pressure system predicted to hit this part of Scotland with 30-40mph winds and heavy rain. 

There were eleven of us setting off up the hill; John, Graham and me as surveyors, with TMS members being Iain Robertson, Alan Brook, David Batty, Anne Butler, Bill Wheeler, Peter Willimott and John Rogerson, with Rab Anderson also present representing the SMC.  With a further four people; Laurence Rudkin, Ian Rudkin, Katy Thompson and Harry Lowe cycling in from the north and planning on joining us on the summit after visiting Ben Avon.

The team, (L-R) Iain Robertson, Alan Brook, Graham Jackson, Rab Anderson, Anne Butler, Bill Wheeler, David Batty, Peter Willimott, John Barnard and John Rogerson

The Balmoral Estate had also given us permission to drive as far as their boundary fence with the next estate which is owned by the Sultan of Brunei, therefore Anne dropped five of us off a further mile up the track before driving back to Inchmore, this gave John, Graham and Alan an opportunity to set off ahead with the surveying gear, and for Iain and me to plod up at a steady pace behind.

Walking up the track to collect our gear

Having never visited the Cairngorms before I was surprised to find them clad in heather, their rolling ridges reminiscent of my local hills; Y Berwyn in mid-Wales, but their scale is vast and seemingly unending. 

Once we collected the gear that Anne had kindly dropped off as far up the track as she could safely drive, we continued by foot on the track as it contoured around the northerly expanse of Cairn Culchavie toward the boundary fence between the two estates.

All around were heather clad hills rising from elongated glens with larger dominating hills in the distance, these still had large amounts of snow sticking firmly to their corried eastern edges.  Sometimes on these surveys time is of the essence, and with the predicted weather worsening in the afternoon we could not linger, but I had a sense of vast openness in these hills, especially so the higher I got, as the landscape then truly opened up showing a land stretching out to a cloudy western horizon, with lower glens bisecting the hills, it seemed a landscape of solitude, but one that had to be respected as the distances were relatively vast when compared to the ones I was used to in Wales.

Looking west with large amounts of snow still on the hills
Our first view of Meall Gaineimh from the descent to Inchrory

The track led down to Inchrory which sat beside the River Avon looking rather grand and somewhat misplaced; however a metalled private road leads to this estate house from the north.  As we approached the estate house Laurence, Katy, Ian and Harry appeared around the corner having cycled in from the north.  They soon continued over the bridge that spans the Builg Burn, I followed with the knowledge that one by one the quicker members of our party would overtake me as we started up the track and continuing path that weaves its way up the northern flank of Meall Gaineimh.

Inchrory, looking rather grand
Laurence, Katy, Ian and Harry crossing the Builg Burn

Knowing what the forecast was I had set off in full waterproofs, but as the ascent of the hill started I felt as if I was walking in a sauna, I stopped and packed my Goretex coat and over trousers in my rucksack and continued up the hill.  One by one people passed me, this is not uncommon and as long as I steadily make progress at my own pace I’m happy enough.

Rab, John and Alan starting the ascent of Meall Gaineimh
John Rogerson on the upper section of Meall Gaineimh

The views were now opening up with cloud skimming some of the higher tops out to the west and banks of snow still in evidence on their sides.  As I approached the summit the granite tor rose up from the rounded summit area and John and Graham were already busy at work positioning the tripod.

Another view west onto a land of remote hills
Setting the Leica GS15 up on the summit tor of Meall Gaineimh

The highest part of the granite tor was on the lip of a four metre vertical drop to its base on its eastern side, because of this the tripod could not be positioned over the high point, therefore a measurement offset was taken between the set-up position and that of the high point.  A staff reading was also taken from the high point to the ground at the base of the cairn which was positioned approximately 100 metres away, the height difference is 2.7m.  This meant that if the height and positioning of the 912m spot height was accurate the summit of Meall Gaineimh was 914.8m high and would surpass the 914.4m / 3,000ft benchmark height by 0.4m.  However, photogrammetry has a margin of uncertainty of +/- 3m and the height may have been spotted to the top of the cairn, this would be relatively easy to do as a photogrammetist is viewing a 3D image from above and the construction of a cairn has similarities to that of a small rock outcrop.

Once the Leica GS15 had been put in place we positioned a number of rocks at the base of the tripod legs to secure it, pressed the button and started collecting data.

Graham beside the Leica GS15 on the summit tor

The tor was ideal for shelter as it proved chilly on the summit with a keen westerly wind, and as we left the equipment gathering data we descended the tor to join everyone on its eastern side, well sheltered from the brisk wind.

Sheltering on the eastern side of the summit tor

A number of people had either headed further west toward the continuing ridge to bag more hills before joining us on the summit, or they now did so.  Now began the long wait, as the Ordnance Survey require a minimum two hour data set to verify the result and this wait can prove a chilly affair on high hills in Scotland.  Thankfully, the predicted rain had not yet arrived and at times even the brisk wind lessened to a slight breeze.

Curve of snow

During this wait we checked the position of the ten figure grid reference for the 912m spot height and confirmed that it is beside the large cairn, I also took a five minute data set with the Trimble at the summit.  This would give us two data sets for the summit and a ten figure grid reference for the highest point of the hill.

Gathering summit data with the Trimble

I spent a number of minutes wandering around the tor taking photos and stood on its lower southerly part admiring the hills to my south and west, the land looked welcoming but a teense wild as the distances were large in comparison to the ones I am used to.

The southern part of the summit tor with Peter heading off to investigate the land beyond the connecting bealach

Once the first hour of data collection had passed we prepared to descend to the connecting bealach and gather data with the Trimble to give the hill an accurate drop value.  On our way down we met Peter who was on his way back up, he’d been out investigating the land beyond the bealach, and we stopped and chatted for a few minutes before continuing downhill.

Meeting Peter on our way down to the bealach
Graham nearing the bealach

The bealach has a small dried up puddle on it and is relatively tight on the hill to hill traverse, as we assessed the ground Alan Brook appeared like a wild man coming out of the wilderness, he was full of smiles and stayed with us as we chose the spot for the Trimble placement.  Once five minutes of data were gathered John, Graham and Alan headed back up the hill and I headed down as I expected those on the summit to catch me up and overtake me on the descent.

Alan Brook emerging out of the wilderness
The set-up position for the Trimble at the bealach

The path that we had followed up the hill does not continue to the summit of Meall Gaineimh, as it continues to its bealach, it was this path that I now followed as it swept around the northern flank of the hill before heading straight down it.  After sorting my gear out and packing the Trimble away I headed down on the path and looked back toward the bealach and the opposing granite tor as the sky turned a foreboding murky grey colour which heralded the incoming rain.

One last look back toward the bealach as the sky turns an ominous grey

I wanted to pace myself on the downhill as we had commented that the inward descent to Inchrory would be a slow uphill grind at the end of the day on our outward journey.  It was good not to think that I had to try and keep up with faster hill walkers on my descent, it was also good to be in such landscape on my own where the hills can take over in preference to conversation.

As I approached the lower section of the hill a party of horse riders were on the track heading for the bridge across the Builg Burn.  Once on the track I slowly made my way over the bridge toward the deciduous wood and the grounds next to Inchrory, and looked back toward Meall Gaineimh as it climbed into the sky heather bound and rounded. 

Horse riders approaching the bridge across the Builg Burn

I stopped for a while to admire the scene of river and hill and watched as five birds flirted across the sky as they flew up stream.  Slowly I plodded up the track beyond Inchrory and was buzzed by a Lapwing as it darted across the landscape.  We had earlier spotted Black Grouse when starting our walk and I now encountered a Red Grouse and her young chicks nestled on the path, as I approached the mother ran off with her chicks in close pursuit, I contentedly watched as the young scampered off down the track and eventually into the surrounding heather.

Taking flight
Meall Gaineimh and the River Avon
Trying to catch my dinner!

By now the sky had turned a silken grey and I noticed that I had instinctively quickened my pace.  As I approached the boundary fence between the two estates a few rain drops were cast down in the breeze, these were on my back and almost unnoticed except for their touch upon puddles that I passed.  I hoped that I may be able to out-pace the incoming rain and set a brisk pace down the continuing track, but the rain increased and when larger drops started to fall and the land infront as well as behind had turned grey I decided it was time to stop and put on my waterproofs.

It seemed a longer journey out of the hill than into it, but slowly the metres disappeared behind me and at last the welcome sight of the cars parked beside Inchmore came into view.  I hoped that I could find shelter either inside this house or beside it, not unexpectedly the front door was locked, but around its eastern side were breeze blocks stacked up to make a relatively comfortable seat which was a welcome surprise.  I spent 30 minutes happily seated here out of the rain as it blew in from the west, waiting for the others to arrive.

It had been an excellent walk, my first into Cairngorn country, which proved an impressive land of rock tor, glen and wild hill.

Survey Result:

Meall Gaineimh

Summit Height:  913.6m (converted to OSGM15, Trimble GeoXH 6000) 913.6m (converted to OSGM15, Leica GS15) (Corbett Top status confirmed)

Summit Grid Reference:  NJ 16683 05113

Bealach Height:  843.9m (converted to OSGM15)

Bealach Grid Reference:  NJ 16431 05220

Drop:  69.7m (Leica GS15 summit and Trimble GeoXH 6000 bealach)

Dominance:  7.63%

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

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