19
Aug
2013
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Knight’s Peak – Britain’s most difficult mountain survey

Following on from the success of Britain’s new mountain back in April this year, we have a guest post from Myrddyn Phillips on his next mountainous challenge.

Balanced precariously on the aptly named Pinnacle Ridge in the Cuillin Mountains of  Skye in the Highlands of Scotland is a lump of rock that may well prove to offer the most difficult mountain survey ever conducted in Britain.

The mountain in question is Knight’s Peak (grid reference NG 471 254).  Its summit is situated amongst castellated peaks in the most challenging and dramatic mountain range Britain has to offer.

The summit of Knight’s Peak consists of two tops a short distance apart.  One top is spacious enough for one person to balance on its highest point, whilst the other is a pointed top where standing is not advised.  The land beyond the summit area is precipitous.

The reason why Knight’s Peak is being surveyed is that it is currently listed as a Munro Top with a height of only 915 m (3,002 ft).  In Scotland the 3,000 ft bench mark height is a magical barrier as it denotes Munro (Separate Mountain) and Munro Top (Subsidiary Top) status.  The Munros are the 3,000 ft Scottish mountains first published in the 1891 Scottish Mountaineering Club Journal and are now known eponymously after Sir Hugh Munro, the person who compiled the list.  They are Britain’s most popular mountains with upwards of 6,000 completers of the list and there are probably three times as many people slowly working their way through the compilation.  So at only just over 3000 ft on the map, Knight’s Peak only just qualifies as a Munro Top in this most famous of lists.

Knight’s Peak is being surveyed by G and J Surveys in conjunction with the Scottish Mountaineering Club and The Munro Society.

In recent times G and J Surveys has carried out the surveys that have led to the reclassification of Sgùrr nan Ceannaichean and Beinn a’ Chlaidheimh from Munro to Corbett status and the team has also determined that Buidhe Bheinn is the higher summit of the twin Corbett Sgùrr a’ Bhac Chaolais/Buidhe Bheinn situated in Glen Shiel.  South of the Scottish border their surveys have elevated Mynydd Graig Goch and Thack Moor to 2,000 ft mountain status.

Will this most difficult mountain survey prove Knight’s Peak to be over the magical height of 3,000 ft or will Knight’s Peak be dethroned and fall off its airy perch?

All will be revealed as the participants gather 10–16 September for Britain’s most difficult mountain survey.

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6 Responses

  1. Reamonn Lenkas

    Hi Gemma,

    Now that this has been confirmed today I would be interested to hear what Knight’s Peak is now designated as. A quick google and social media search doesn’t reveal any answers. Has it now joined another famous list and become a Corbett or a Corbett top? Surely this would become the most challenging Corbett and worthy of an article?

    Regards

  2. Dr Leslie V Morrison

    The report in The Times today states that Knight’s Peak is 6.5 inches below the 3000 feet level. I presume that the mountaineers took into account the solid earth tides in their measurement. I am not sure what the amplitude of the tides is for that region of the Earth, but they can reach an amplitude of about 40 cm (about 16 inches) in a semi-diurnal cycle. So, the result for the height of the peak would be critically dependent on when the measurements were taken. The Times reports a period of 2 hours. This would not be sufficient to smooth out the fluctuation in height due to solid earth tides. Perhaps a mathematical calculation was used to subtract the effect of solid earth tides in the measurements?

    1. Gemma

      Hi Leslie,

      The final coordinates for Knight’s Peak were computed by Ordnance Survey using state of the art scientific processing software (‘Bernese Software’) which models both solid Earth tides and also the impact of ocean tide loading. The resulting height is therefore free of tidal effects. The height accuracy is +-30mm.

      Thanks

  3. Dr Leslie V Morrison

    Thank you. It was as I suspected. However, the height of the peak must fluctuate around 3000 feet, and therefore maybe it should still qualify as a Munro?

    1. Gemma

      Hi Leslie,

      Of course all land does fluctuate up and down on a regular basis under the influence of various “tides” both within and upon the Earth. However this is no good for surveying and mapping since a stable reference frame is required within which to work and within which all features are coordinated. For satellite positioning in GB the stable reference frame is known as ETRS89 and is realised by the accurate (2mm in plan, 6mm in height) coordinates of the 108 OS Net permanent GNSS stations around the country (http://www.ordnancesurvey.co.uk/business-and-government/products/os-net/index.html).

      The position of Knight’s Peak was fixed relative to the surrounding OS Net stations and, as previously stated, this relative position is free of the influence of tides due to the use of sophisticated models within the processing software. So the surveyed height of Knight’s Peak is tide free and fixed in ETRS89.

      The height of 3000’ in this country specifically means 3000’ above mean sea level (MSL). MSL in GB is defined by Ordnance Datum Newlyn (ODN) and physically realised across GB by a network of high accuracy fundamental bench marks (FBMs). The FBM heights, and therefore ODN, are related to ETRS89 using a geoid model (currently OSGM02). The geoid model relates the varying difference between height in ETRS89 and ODN height. The 914.24m MSL height of Knight’s Peak comes from the ETRS89 height and OSGM02. It is therefore fixed in the official height reference frame of GB and, for positioning/mapping/Munro classification purposes, does not move. The estimated height quality of +-30mm comes from an estimate of the errors in the whole process from observation to conversion to ODN.

      Hope this helps
      Gemma

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