Mapping Mountains – Significant Height Revisions – The 500-Metre Tops of England and Wales – Deweys

Craig Dolfudr – North Top (SH 822 317) 

There has been a Significant Height Revision to a hill that is listed in the The 500-Metre Tops of England and Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Craig Dolfudr - North Top (SH 822 317)

The criteria for the list that this height revision applies to are:

The 500-Metre Tops of England and Wales are affectionately known after their hill list compiler; Michael Dewey.  This list mixes metric and imperial height in its criteria to bookend up to the 2000ft height band and takes in all hills in England, Isle of Man and Wales that are 500m and above and below 2000ft (609.6m) in height that have 30m minimum drop. 

Mountain tables by Michael Dewey

Michael Dewey died on the 5^th November 2022.  His wife; Gillian wished for this list to be carried on and made provision for it to be co-authored by Myrddyn Phillips.  Michael will always be the compiler and originator, it’s just that he’s now got a co-author to safeguard and carry this list on.

The name given the hill by Michael Dewey is Craig Dolfudr – North Top and it is adjoined to the Arenig Fawr group of hills, which are situated in the central part of North Wales, and it is positioned with a minor road to its north and the A494 road to its south-east, and has the small community of Llanuwchllyn towards the east south-east.

Extract from the Ordnance Survey 1:50,000 Landranger map

When the original list of Deweys appeared in the Mountain tables book published by Constable in 1995, this hill was listed with a 519m summit height, based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

Extract from the Ordnance Survey 1:25,000 Explorer map

Since the original publication of this list there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites, and it is the Ordnance Survey series of Six-Inch maps that formed the basis in the change of the listed height of this hill.

The Ordnance Survey series of Six-Inch maps formed the base map Ordnance Survey used for many decades leading to the production of the 1:10,000 Series of maps, both have now been superseded by the digitised Master Map, and it is this series of maps that give a 1709.9ft (521.18m) Bench Mark on the summit of this hill. 

Extract from the Ordnance Survey series of Six-Inch maps

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Craig Dolfudr - North Top (SH 822 317)

LIDAR analysis gives the summit of this hill as 521.4m positioned at SH 82250 31702, and this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey, Harvey or other interactive map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or other GNSS equipment or analysis of data produced via LIDAR.  Also included are hills whose summit map data is missing an uppermost ring contour when compared with the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 521.4m and this was derived from LIDAR analysis, this is 2.4m higher than the originally listed summit height of 519m, which was based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

 

The full details for the hill are:

Group:  Arenig Fawr

Name:  Craig Dolfudr – North Top

OS 1:50,000 map:  124, 125

Summit Height (New Height):  521.4m (LIDAR)

Summit Grid Reference:  SH 82250 31702 (LIDAR)  

Bwlch Height:  444.8m (LIDAR)

Bwlch Grid Reference:  SH 81324 31319 (LIDAR)

Drop:  76.6m (LIDAR)

 

Myrddyn Phillips (November 2026) 

Mapping Mountains – Hill Reclassifications – The Fours – The 400m Hills of England

Doe Tor (SX 542 848) – Sub-Four addition

There has been an addition to the listing of the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Doe Tor (SX 542 848)

The criteria for the list that this addition applies to are:

The Fours – The 400m Hills of England - English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list is a sub list entitled the Sub-Fours, the criteria for which are all English hills at or above 400m and below 500m in height that have 15m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available to download in Google Doc format from the Mapping Mountains site.

The Fours - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Doe Tor, and it is adjoined to the High Willhays group of hills, which are situated in the south-west of England, and it is positioned with the A386 road to its west, and has the village of Lydford also towards the west.

When the Introduction to the first group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published by Mapping Mountains on the 10^th September 2022, it was announced that the accompanying sub lists were being revised with the two 390m categories dispensed with and the criteria and name of the 400m Sub-Fours revised.  The one accompanying sub list is now named the Sub-Fours with its criteria being all English hills 400m and above and below 500m in height that have 15m and more and below 30m of drop.

Prior to this revision this hill was not listed, as although the Ordnance Survey 1:25,000 Explorer map has a 425m summit spot height, it is missing the 410m and 420m ring contours for this hill, which makes interpolation for the col height and the drop value difficult. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the addition of this hill to Sub-Four status is due to LIDAR analysis, resulting in a 424.9m summit height and a 407.6m col height, with these values giving this hill 17.3m of drop, which is sufficient for it to be classified as a Sub-Four. 

 

The full details for the hill are:

Group:  High Willhays

Name:  Doe Tor

OS 1:50,000 map:  191

Summit Height:  424.9m (LIDAR)

Summit Grid Reference:  SX 54204 84832 (LIDAR)

Col Height:  407.6m (LIDAR)

Col Grid Reference:  SX 54413 84829 (LIDAR)

Drop:  17.3m (LIDAR)

 

For the additions, deletions and reclassifications to The Fours – The 400m Hills of England reported on Mapping Mountains since the December 2013 publication of the 1^st edition of this list by Europeaklist please consult the following Change Registers:

 

The Fours

 

Sub-Fours

 

Myrddyn Phillips and Aled Williams (November 2026)               

Mapping Mountains – Trimble Surveys – Mullach Coire Mhic Fhearchair

 

08.07.26  Meall Leac an Fhaobhair (NG 895 968) and Meall na Creige Moire (NG 889 973)

Meall Leac an Fhaobhair (NG 895 968)

Being based in Laide gave us opportunity for a variety of walking, but as we were staying in Mark’s home away from home there were a number of tasks needed doing, one being pulling of invasive thistles.  Therefore, the morning was a relatively easy affair with internet catching up including the writing of the first draft for the Yr Wyddfa bwlch survey post, breakfast and the later preparation of lunch and of course the pulling of those aforementioned thistles, which John and I set about with enthusiasm, clearing a large patch of land leading to and just beyond the front door.  This relatively leisurely start to the day also enabled the weather to improve, from the overcast morning skies to increasingly blue, and by the time we were ready to depart for an afternoon walk the overhead conditions were positively sublime.

We had two small hills on our radar, each overlooking the north-eastern part of the peninsula to the immediate north-west of Laide.  Coastal walking can be invigorating with views out to sea and brisk breeze, and today it was just that with the added bonus of vivid colouring to both the sea and the land.

My main walking ground is Wales, and although I’ve been to Scotland and walked various hills over the years, I wouldn’t profess to know either the country or its hills.  One of the aspects I enjoy about the Welsh uplands is the variety of its hills and landscape, but during occasional forays north I was all too aware of the shear scale of what Scotland has to offer and today the microcosm of land we were visiting was an example of where those Welsh beauties were multiplied tenfold when in Scotland.  It is the shear scope, variety, number and height of hills that amaze. 

Deep blues of the sea

We parked at the road end where a number of tents and camper vans were positioned overlooking the most beautiful beach.  The colour was spectacular and reminded me of past visits to Greek islands with the azure of the deep blue sea and succulent blue sky contrasting against the light coloured sand and all looking upon a backdrop of high hills lined up across the water.  It really was a marvellous sight. 

Our walk started on the beach, when seldom do in Wales where hills are involved.  I happily crossed the outflow of a fresh water burn as it widened in to the depths of salty water. The sands soon gave way to large and smoothed rocks consisting of a multitude of colour.  As I headed up on to a narrow green path that was evident from the higher part of the large rocked section Mark and John caught me up.  I then followed my colleagues feeling content whilst taking numerous photographs, as the landscape unerringly set itself against the most stunningly beautiful view where both the foreground and background were perfectly aligned. 

Ben Mór Coigach

Nearing the summit of our first hill of the day

The path became slightly boggy in places, but never so difficult to course concern.  It led in time over an intermediary bump before gaining height on its way past Loch Dubh na Maoil before gaining height to the summit of our first hill of the day; Meall Leac an Fhaobhair.  The high point of the hill was positioned about 4 metres from the base of a relatively large cairn and the Trimble was soon set up gathering its first five minute data set.  As data were collected I scribbled all necessary information in my surveying notebook as my two colleagues stood looking out to sea and examining our next objective which was close at hand to our north-west.  Once data were gathered and stored, I closed the equipment down, took a few photographs and joined Mark and John as we headed down to the connecting bealach. 

Meall na Creige Moire from Meall Leac an Fhaobhair

Gathering data at the summit of Meall Leac an Fhaobhair

This part of the walk was especially stunning with coastal crags immediately on our right and the sea stretching beyond to distant islands.  Again the going was slightly boggy but not enough to hinder. 

Mark on the path between the two hills

Approaching the summit of the second hill

On the first summit I’d collected data at approximately quarter past the hour and wanted to collect data from the top of our second hill; Meall na Creige Moire in the same hour range, by doing so only one set of data would need downloading and then converting to Rinex 2 from the Rinex 3 data now offered by Ordnance Survey.  Therefore, having crossed the bealach I was in head down and fast plodding mode arriving at the next summit before my two companions and having the Trimble placed on the hill’s high point and ebbing down to its 0.1m accuracy level before data should be logged before John and then Mark joined me for more sea views. 

The summit of Meall na Creige Moire

The Trimble set-up position at the summit of Meall na Creige Moire

From this vantage point it seemed as if we were positioned near the edge of the earth with islands off in the distance and blue azured sea below.  The onward part of the walk aimed for a cairn placed atop a small rise. Between us and it was a watery course of bog channels, again all easy to avoid and none drastic enough to detract from the overall beauty of the walk. 

Leaving the small cairned bump and heading down to join the outward track

On the track

Another good day on the hill

A path led down from the small cairn on to a wider track that in time swung back to rejoin our starting point.  By now I was more than content to bring up the rear and enjoy the scenery of rock and sea and those stunningly sublime colours that were on grand display, with strings of white and grey clouds streaming across that succulent blue sky and those deep coloured blues of the sea, all interspersed with the varied grey coloured rock and the greenery of the hills.  Such a marvellous place to visit and a walk I would recommend anyone doing if ever the opportunity arises. 

 

Survey Result: 

 

Meall Leac an Fhaobhair

Summit Height:  54.0m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision) 

Summit Grid Reference:  NG 89519 96856 (Trimble GeoXH 6000) 

Bealach Height:  c 19m (interpolation)

Bealach Grid Reference:  NG 89162 97013 (interpolation)

Drop:  c 35m (Trimble GeoXH 6000 summit and interpolated bealach)

Dominance:  64.84% (Trimble GeoXH 6000 summit and interpolated bealach)

 

 

Meall na Creige Moire

Summit Height:  55.3m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  NG 88972 97371 (Trimble GeoXH 6000) 

Bealach Height:  c 12m (interpolation)

Bealach Grid Reference:  NG 88459 96413 (interpolation)

Drop:  c 43m (Trimble GeoXH 6000 summit and interpolated bealach)

Dominance:  78.30% (Trimble GeoXH 6000 summit and interpolated bealach)

 

 

My thanks to Alan Dawson with help processing these data

 

For further details please consult the Trimble Survey Spreadsheet

Monthly Synopsis

 

Synopsis of all major changes detailed on Mapping Mountains during the last calendar month.  These can include new, confirmation and retrospective changes

 

Hill Reclassifications: 

Boncyn Nadroedd (SJ 027 540) - 390m Double Sub-Pedwar reinstatement

Foggintor Quarry (SX 566 735) - Sub-Four addition

Bryn Engan (SH 720 568) - Welsh P15 addition

 

Significant Height Revisions: 

Braich Bryn Engan (SH 723 569) - The Welsh P15s

Foggintor Quarry (SX 566 735) - The Fours - The 400m Hills of England

Bryn Engan (SH 720 568) - The Welsh P15s

Summit Relocations: 

Top Piece (SO 101 641) - 200m Twmpau

Significant Name Changes: 

Ffridd Uchaf (SH 799 668) - 100m Twmpau

Mapping Mountains – Significant Height Revisions – The Welsh P15s

 

Braich Bryn Engan (SH 720 568) 

There has been a Significant Height Revision to a hill that was listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Braich Bryn Engan (SH 720 568)

The criteria for the list that this height revision applies to are:

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is listed by is Braich Bryn Engan, and it is adjoined to the Moel Siabod group of hills, which are situated in the north-western part of North Wales (Region C, Sub-Region C1A), and it is positioned with the A4086 road to its north-west and the A5 road to its north-east, and has the village of Capel Curig towards the north.

When the listing that became known as The Welsh P15s was being compiled, this hill was not included in either the main list or the accompanying sub list, with subsequent interpolation giving the hill an estimated c 335m summit height and an estimated c 327m bwlch height, with both heights based on interpolation of 10m contouring. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Braich Bryn Engan (SH 720 568)

The summit height produced by LIDAR analysis is 339.9m and when compared to the interpolated summit height, this comes within the parameters of the Significant Height Revisions used within this page heading, and these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey, Harvey or other interactive map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR.  Also included are hills whose summit map data is missing an uppermost ring contour when compared with the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 339.9m and this was derived from LIDAR analysis.  This is 4.9m higher than the previously estimated summit height of c 335m, which was based on interpolation of the uppermost 330m ring contour that appears on the Ordnance Survey 1:25,000 Explorer map. 

 

The full details for the hill are: 

Group:  Moel Siabod 

Name:  Braich Bryn Engan 

OS 1:50,000 map:  115

Summit Height (New Height):  339.9m (LIDAR) 

Summit Grid Reference:  SH 72062 56877 (LIDAR)                                                  

Bwlch Height:  334.0m (LIDAR) 

Bwlch Grid Reference:  SH 71985 56818 (LIDAR) 

Drop:  15.9m (LIDAR) 

                                                           

My thanks to Aled Williams for advice relating to the listed name of this hill

Myrddyn Phillips (October 2026)