Mapping Mountains – Hill Reclassifications – Y Pedwarau – The 400m Hills of Wales

Lan Fawr (SN 692 501) – Pedwar reclassified to 400m Sub-Pedwar

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 survey conducted on the 5^th January 2020 by Myrddyn Phillips with assistance from Rob Woodall, with subsequent LIDAR bwlch analysis prioritised.

Lan Fawr (SN 692 501)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are five categories of sub hills, with this hill being reclassified to the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

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

The name the hill is listed by is Lan Fawr, and it is adjoined to the Esgair Wen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with the Afon Teifi and the B4343 road to its north-west and the A482 road to its south-west, and has the village of Llanbedr Pont Steffan (Lampeter) towards the west.

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with 28m of drop, based on the 429m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 401m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and which is positioned at SN 69498 50464.  This spot height is also shown on Ordnance Survey data that appears on the Magic Maps website. 

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

The details for this hill were re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on the Ordnance Survey 1:25,000 Explorer map and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 30m of drop, based on interpolation of 5m bwlch contouring between 395m – 400m.

The Trimble GeoXH 6000 gathering data at the summit of Lan Fawr

The 401m spot height that appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map originates from a 1316ft (401.1m) imperial height that appears on the Ordnance Survey series of Six-Inch maps.  This seems to be a levelled height and was not necessarily taken to the critical point of this bwlch.  As a consequence of these re-assessments this hill was reclassified to a Pedwar with an estimated c 30m of drop.

The Trimble GeoXH 6000 gathering data on the bwlch area of Lan Fawr

However, it was not until The Trimble GeoXH 6000 survey and subsequent LIDAR analysis 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 image of Lan Fawr (SN 692 501)

Therefore, the reclassification of this hill to 400m Sub-Pedwar status is due to a Trimble GeoXH 6000 survey and subsequent LIDAR analysis, resulting in a 427.4m summit height and a 398.2m bwlch height, with these values giving this hill 29.2m of drop which is insufficient for it to be classified as a Pedwar.

The full details for the hill are:

Group:  Esgair Wen

 

Name:  Lan Fawr

OS 1:50,000 map:  146

Summit Height:  427.4m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 69244 50156 (Trimble GeoXH 6000)

Bwlch Height:  398.2m (LIDAR)

Bwlch Grid Reference:  SN 69489 50456 (LIDAR)

Drop:  29.2m (Trimble GeoXH 6000 summit and LIDAR bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (May 2020)

Mapping Mountains – Trimble Surveys – Esgair Wen

05.01.20  Lan Fawr (SN 692 501), Cerrig Cyffion (SN 689 479) and Esgair Fawr (SN 681 482)  

Cerrig Cyffion (SN 689 479)

Within the updated list of the Y Pedwarau – The 400m Hills of Wales, Lan Fawr has been reclassified from a 400m Sub-Pedwar to a Pedwar, as such it is a new P30.  This newly crowned status is based on OS Maps 5m bwlch contouring and is of interest to a number of people, including Rob Woodall, who has visited all Welsh mainland P30s; which is an incredible achievement.  Therefore, as Rob had not visited this hill, he wanted to. 

Rob arrived Saturday evening and we were soon in The Raven enjoying an excellent meal.  We were away by 7.30am on Sunday heading to the wild landscape south of Llanddewibrefi and north of the small community of Ffarmers.

Weather conditions were not ideal, with mist and drizzle for the majority of the journey.  However, as we set off walking the mist hugging the opposing ridge of Garn Fawr (SN 668 502) slowly lifted and pushed further inland.

We planned a three hill circuit around the upper reaches of the Afon Cothi, with Lan Fawr and Cerrig Cyffion being of particular surveying interest with both hills considered for reclassification to Pedwar status.  Hopefully the Trimble would give a definitive result for each.

A track led from the last farm in the valley; Blaen-Twrch, making steady progress up the south-western flank of our first hill of the day; Lan Fawr.  Encircling us gloom pervaded, with higher summits cloaked in mist with banks of mist rolling in from the lowlands to our south heralding intermittent drizzled conditions.

Heading to the hill

We spent quite some time at the summit of Lan Fawr taking three data sets with the last beside the remains of a flattish cairn which was our favoured position for the high point.  During data collection a number of sheep walked our way, standing facing us either expectant of feed or just being inquisitive.  They made an appealing foreground to the misted hills in the distance.

Gathering data at the summit of Lan Fawr

Being watched

The hill’s grassed north-eastern ridge soon led us down to a tussocky bwlch, and soon the Trimble was positioned on top of my rucksack gathering data.  As the equipment gathered its allotted data we stood back and looked out on the mass of unsavoury but nevertheless beautiful yellow tinged land between us and the haven of green grass atop a small ridge which would take us down to a track leading toward our second hill of the day; Cerrig Cyffion.

Gathering data on the bwlch area of Lan Fawr

Once data were gathered and stored I closed the Trimble down, packed it away and followed Rob as he contoured around the upper easterly flank of Lan Fawr, eventually loosing height down through dark browned bracken to a reed invested stream where he easily jumped its watery depths.  I however made an unceremonious landing with my left foot slipping on the bank and dangling over the stream which resulted in Rob trying to hold on to me and the two of us landing heap like on the ground.

Leaving Lan Fawr and heading toward Cerrig Cyffion

By now each drizzly spell would be replaced by a semblance of clarity and semi-dryness, and considering the surrounding conditions we were lucky as all surveys were conducted clear of mist and it did not hamper navigation.

Making progress toward Cerrig Cyffion

We gained height above the stream with Rob unsurprisingly leading the way seemingly at only a quarter of his normal pace as I huffed and puffed on the uphill section.  A muddied track led us down to a stream crossing where an old track led past the ruined Blaen Cothi.  This old house must have been a wild place to make a life.

Blaen Cothi with Cerrig Cyffion in the background

The muddied track met a more recent construct which wound its way around the northern and eastern flank of Cerrig Cyffion, we soon left it and opted for a path leading up its northerly ridge.  By the time I reached the summit Rob was standing beside one of a number of small rocks jutting out of the ground and had declared this the high point.  The Trimble was soon aligned with this, a measurement offset taken and away it went, gathering its allotted data.  During data collection I stood and munched on a banana, my only sustenance of the walk.

Gathering data at the summit of Cerrig Cyffion

The bwlch adjoined to Cerrig Cyffion is just to the north-west of the continuation of the track which had wound its way higher on the hill.  This bwlch was particularly unpleasant with large tussocks predominating.  We spent a number of minutes assessing the bwlch and visually followed the hill to hill traverse to a point that we judged bisected the valley to valley traverse and used an upended red animal feed bucket as an improvised tripod, and as my rucksack was positioned on its top and the Trimble atop this it gave a 0.70m offset between its internal antenna and the ground at its base and was sufficiently high enough to clear the large tussocks.  Just one hill now remained.

Heading toward the bwlch of Cerrig Cyffion

Gathering data at the bwlch of Cerrig Cyffion

The Trimble set-up position at the bwlch of Cerrig Cyffion

Esgair Fawr is the highest of the three hills we visited and between us and its summit was another large mass of tussocks and bog.  To get there we circumvented the edge of a conifer plantation and contoured grassed slopes toward the bwlch.  This gave an advantage point to look down and judge where the critical point lay.  As Rob ventured further in to the mass of bog and tussocks I assessed the ground and chose a spot and placed the rucksack on top of a tussock and waited for Rob to re-join me with his assessment.  He considered the position good and we both then stood an appropriate distance away as data were gathered.

Gathering data at the bwlch of Esgair Fawr

It was a steady plod to the summit of Esgair Fawr and Rob was there waiting for me when I arrived.  The high point is at the base of a fence that is on top of a grassed over stone wall.  As the grassed stone wall was considered unnatural I positioned the Trimble on what we judged the highest natural point of the hill and the day’s eighth data set was gathered.

Gathering data at the summit of Esgair Fawr

All that remained was to join our downward track and head back to the awaiting car.  However, Esgair Fawr has a twin map heighted top which stared back at us as it balanced above a small rock carved drop.  Aled had LIDARed this hill and the point that had just been Trimbled proved to be the higher, we also thought this visually, but as we were there, Rob suggested a last data set and soon the Trimble was placed aligned with this tops highest point and quietly beeping away gathering data.

Once the Trimble was packed away we headed toward the track and its steep zig zags forever downward to the car.  It was good to get these hills surveyed, and especially Lan Fawr and Cerrig Cyffion as these two hills could be 400m Sub-Pedwarau or indeed Pedwarau.  It was also good to catch up with Rob, without whom I would have waited another few months before attempting this walk which had been penciled in as one of this year’s priority surveys.

LIDAR image of Lan Fawr (SN 692 501)

Postscript:

Since visiting 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 LIDAR being prioritised over some of the results produced by surveying with the Trimble GeoXH 6000. 

Survey Result:

Lan Fawr 

 

Summit Height:  427.4m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 69244 50156 (Trimble GeoXH 6000)

Bwlch Height:  398.2m (LIDAR)

Bwlch Grid Reference:  SN 69489 50456 (LIDAR)

Drop:  29.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) (Pedwar reclassified to 400m Sub-Pedwar)

Dominance:  6.83% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Cerrig Cyffion 

 

Summit Height:  414.8m (converted to OSGM15)

Summit Grid Reference:  SN 68924 47937

Bwlch Height:  386.1m (converted to OSGM15)

Bwlch Grid Reference:  SN 68829 47667

Drop:  28.7m (400m Sub-Pedwar status confirmed)

Dominance:  6.91%

Esgair Fawr 

 

Summit Height:  412.4m (converted to OSGM15)

Summit Grid Reference:  SN 68189 48249

Bwlch Height:  361.5m (converted to OSGM15)

Bwlch Grid Reference:  SN 68287 47838

Drop:  50.9m

Dominance:  12.34%

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains – Hill Reclassifications – Y Pedwarau – The 400m Hills of Wales

THIS HILL HAS SUBSEQUENTLY BEEN RECLASSIFIED BACK TO SUB-PEDWAR STATUS

Lan Fawr (SN 692 501) – 400m Sub-Pedwar reclassified to Pedwar

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary Ordnance Survey maps.

Lan Fawr (SN 692 501)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified from the 400m Sub-Pedwar category.  The criteria for 400m Sub-Pedwar status being all Welsh hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

The name the hill is listed by is Lan Fawr, and it is adjoined to the Elenydd group of hills, which are situated in the northern part of Mid and West Wales (Region B, Sub-Region B2), and it is positioned with the Afon Teifi and the B4343 road to its north-west and the A482 road to its south-west, and has the village of Llanbedr Pont Steffan (Lampeter) towards the west.

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

When the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013, this hill was listed as a 400m Sub-Pedwar with 28m of drop, based on a 429m summit height that appears as a spot height on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and a 401m bwlch height that appeared as a spot height on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map and which is positioned at SN 69498 50464.  This spot height is also shown on Ordnance Survey data that appears on the Magic Maps website. 

Extract from the Magic Maps website

The details for this hill were re-assessed when the OS Maps website became available online.  This is the replacement for OS Get-a-map and has contours at 5m intervals which are proving consistently more accurate compared to the 5m contours that sometimes appear on Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the hill being listed with an estimated c 30m of drop, based on interpolation of 5m bwlch contouring between 395m – 400m.

Extract from the OS Maps website

The 401m spot height that appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map originates from a 1316ft (401.1m) imperial height that appears on the Ordnance Survey series of Six-Inch maps.  This seems to be a levelled height and was not necessarily taken to the critical point of this bwlch.

Extract from the Ordnance Survey series of Six-Inch maps

Therefore, the reclassification of this hill from 400m Sub-Pedwar to Pedwar status is due to re-assessment of detail on contemporary Ordnance Survey maps, resulting in a 429m summit height and an estimated c 399m bwlch height, with these values giving this hill c 30m of drop which is sufficient for it to be classified as a Pedwar.

The full details for the hill are:

Group:  Elenydd 

Name:  Lan Fawr

OS 1:50,000 map:  146

Summit Height:  429m (spot height)

Summit Grid Reference:  SN 69253 50157 (spot height)

Bwlch Height:  c 399m (interpolation)

Bwlch Grid Reference:  SN 69480 50453 (interpolation)

Drop:  c 30m (spot height summit and interpolated bwlch)

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

Y Pedwarau

Y Pedwarau – 400m Sub-Pedwarau

Y Pedwarau – 390m Sub-Pedwarau

Y Pedwarau – 390m Double Sub-Pedwarau

Myrddyn Phillips and Aled Williams (March 2020)