Monday 30 November 2020

Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales and 200m Twmpau


Square Field (SJ 070 031) – Trichant reclassified to 200m Twmpau

There has been a reclassification to the list of Y Trichant – The 300m Hills of Wales and the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips.

Square Field (SJ 070 031)

The criteria for the two listings that this reclassification applies to are:

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13th May 2017.

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

The 200m Twmpau by Myrddyn Phillips

The name the hill is being listed by is Square Field and this was derived from local enquiry, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is encircled by minor roads, with also the A458 road to its north, the A470 road to its south-west and the B4389 road to its east, and has the village of Adfa towards the south south-west.

When the original 300m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list and listed with a 300m summit height, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.

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 image of Square Field (SJ 070 031)

The result produced by LIDAR analysis gives this hill a 299.4m summit height, and as the summit has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes.

The Trimble GeoXH 6000 gathering data at the summit of Square Field

Therefore, the confirmation of the reclassification of this hill from Trichant status is due to LIDAR analysis and a Trimble GeoXH 6000 survey, resulting in 45.8m of drop, with a 299.4m summit height and a 253.6m bwlch height, with the summit height insufficient for Trichant status the therefore the hill is reclassified to a 200m Twmpau


The full details for the hill are:

Group:  Carnedd Wen

Name:  Square Field

OS 1:50,000 map:  136

Summit Height:  299.4m (converted to OSGM15, Trimble GeoXH 6000)
                                                           
Summit Grid Reference:  SJ 07034 03161 (Trimble GeoXH 6000)

Bwlch Height:  253.6m (LIDAR)

Bwlch Grid Reference:  SJ 06533 03161 (LIDAR)

Drop:  45.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)


Myrddyn Phillips (November 2020)






Sunday 29 November 2020

The 500-Metre Tops of England and Wales – the Deweys


Y Drum (SJ 082 378) – Dewey addition

The listing to The 500-Metre Tops of England and Wales appeared in Michael’s Mountain tables book which was published by Constable in 1995.  This list mixed metric and imperial height in its criteria to bookend up to the 2000ft height band and listed hills between 500m – 2000ft (609.6m) in height with 30m minimum drop.

Mountain tables by Michael Dewey

Since publication of this list there have been a number of status changes to it. In recent years this has involved independent surveyors and the use of LIDAR.  Both have enabled an accurate re-assessment of many of the hills included in Michael’s list as well as potential new Deweys that were considered marginal on height and/or drop and not initially included. 

Michael Dewey is in receipt of the survey details relating to this hill and has confirmed its addition to his list of The 500-Metre Tops of England and Wales.

Y Drum (SJ 082 378)

 

Dewey addition:

Y Drum (SJ 082 378) was surveyed using the Trimble GeoXH 6000 whilst on a walk with Aled Williams and Mark Trengove, the hill is positioned in the north-western Berwyn and situated between Moel yr Henfaes (SJ 077 385) and Cefn Dylif (SJ 089 369).

The Trimble GeoXH 6000 gathering data at the summit of Y Drum

 

Survey details: 

Name:  Y Drum 

Summit:  579.1m at SJ 08247 37893 

Bwlch:  549.0m at SJ 08003 38256 

Drop:  30.1m 

 

Myrddyn Phillips (November 2020)

 

 

 

 

 

 

 

 

 

 

 



 

 

 

 

 

 

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


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

There has been a deletion 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 maps produced from Ordnance Survey data.

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

Y PedwarauThe 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 deleted from the 390m Double Sub-Pedwar category.  The criteria for this sub category being all Welsh hills at or above 390m and below 400m 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 Boncyn Nadroedd and it is adjoined to the Mynydd Hiraethog group of hills which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is positioned with minor roads to its north, west and east, and has the town of Rhuthun (Ruthin) towards the east north-east.

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was not included in the Hills to be surveyed sub list that accompanied the main P30 list, as it was considered not to meet the criteria then used for this sub category. 

When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 23m of drop, based on interpolated values of c 390m and c 367m for its summit and bwlch respectively, with each based on interpolation of 10m contouring on the Ordnance Survey 1:25,000 Explorer map, and these were the details that it appeared under after the 390m sub categories were added to the Y Pedwarau list.

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 Ordnance Survey 1:25,000 Explorer maps and used to appear on the online Vector Map Local.  This re-assessment resulted in the estimated bwlch height for this hill being amended to c 368m, with this based on interpolation of 5m contouring between 365m – 370m.

Extract from the Magic Maps website

The details for this hill were also re-assessed against Ordnance Survey data hosted on the Magic Maps website as well as the WalkLakes website, and what was thought to be a tiny uppermost 390m summit ring contour is given a 389m spot height on these two interactive maps, implying that what was taken as a small ring contour on the Ordnance Survey 1:25,000 Explorer map, is in fact a spot height missing its 389m height.

Extract from the WalkLakes website

Therefore, the deletion of this hill from 390m Double Sub-Pedwar status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 389m summit height and a c 368m bwlch height, with these values giving this hill c 21m of drop, which is insufficient for it to be classified as a 390m Double Sub-Pedwar.


The full details for the hill are:

Group:  Mynydd Hiraethog

Name:  Boncyn Nadroedd

OS 1:50,000 map:  116

Summit Height:  389m (spot height)

Summit Grid Reference:  SJ 02740 54035 (spot height)

Bwlch Height:  c 368m (interpolation)

Bwlch Grid Reference:  SJ 02565 54068 (interpolation)

Drop:  c 21m (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:










Aled Williams and Myrddyn Phillips (November 2020)





Saturday 28 November 2020

Mapping Mountains – Trimble Surveys – Carnedd Wen


26.08.20  Sixteen Acres (SO 120 987), Moel y Lump (SO 120 997), Pt. 275.1m (SO 131 995), Pen y Gaer (SO 139 976, summit previously Trimbled, only bwlch surveyed), Field Above The House (SO 135 990), Pt. 218.8m (SO 122 978), Henfaes Common (SO 120 974), Cow Pasture (SO 110 977) and Crasty Frain (SO 109 983, previously Trimbled)  

Sixteen Acres (SO 120 987) with Pt. 275.1m (SO 131 995) in the background on the left

The area around the small communities of Tregynon and Betws Cedewain drew me back again, the third time since the five mile local restriction due to the Covid-19 pandemic was lifted in Wales.  This area takes in other villages and hamlets, including Llanwyddelan, Adfa, New Mills and Llangugan, all are nestled amongst farming land, with stream valleys below and grazing fields above.  This land is typical mid-Walian; it has a pleasantness and quietness to it and is seldom visited by the hill walker.

Today I planned on visiting eight summits and had examined each via LIDAR, some weren’t covered, but the details for each that were, were noted.  The hills comprise a variety of classifications with four being P30s, two being subs and two about to be confirmed via the Trimble what LIDAR was stating as deleted subs.  With two bwlch surveys also included, with one adjoined to Pen y Gaer (SO 139 976) which had previously been Trimbled and a few farms to call at en route, the circular walk would give lots of variety for hills, surveys and place-name enquiries.

The forecast predicated better weather as the day progressed, although with the possibility for a shower mid-afternoon.  I was parked and walking up the continuation of the narrow lane that heads eastward out of Tregynon by 10.10am.  Patches of blue mingled with the white cloud as glimpses of sunlight pieced through highlighting the green pastured fields dotted with white specks of sheep.

The lane led to a small cross roads where I turned left heading up toward the farm of Moel y Wigoedd, as I did so a quad bike towing a trailer appeared, I flagged it down and then spent ten minutes chatting with Paul Marsh who rents land on the first hill I planned on visiting.  Paul told me the names he uses for the high field where the summit of this hill is situated and suggested I should call at Alan Jones’s house, which was further up the lane, as he owned the land and would doubtless know the proper field name.  Before leaving Paul, I asked his permission to visit the summit and this was duly given.

Thanking Paul I continued toward the first hill using a gate to access the upper field and a few minutes later the Trimble was set up, beeping away gathering data.  From this vantage point I could follow my planned route over the high field tops as it headed eastward before doubling back south-westward.  As long as the rain kept off I was in for a treat!

Gathering data at the summit of Sixteen Acres

Another gate gave access back to the lane and I followed this up to Alan Jones’s house, where I met his son; Ryan.  We stood outside with the field that I had just surveyed behind us and Ryan told me it is known as Sixteen Acres.  These high fields that comprise summits of what hill bagger’s refer to as hills are seldom known by individual names as local residents and farmers alike would not necessarily recognise them as hills, they are just high fields and therefore using the name of the upper field where the summit of the hill is situated is an appropriate naming protocol for listing purposes and one that is more in tune with historical and also contemporary usage when compared to the transposed use of farm names that may have no direct association with the respective hill, or the use of invented or directional names.

Thanking Ryan, my next port of call was Moel y Wigoedd where I met Ian Jerman and his sister.  We chatted for a number of minutes in the farmyard and soon afterward I was sitting in a vehicle as Ian drove to the top of the next hill.  He knows this hill as Moel y Lump or The Lump and it was the highest on the day’s walk and a fine viewpoint looking out toward the distant Aran and a part of the Cadair Idris range just poking above the intervening land.

I showed Ian the Trimble and quickly explained the set-up procedure and then assessed the lay of land for the hill’s high point, which was not too difficult a process on this particular hill.  Ian told me of the jovial competitiveness between himself and his neighbour at Bryncaemaeshir relating to whose hill was highest.  Soon the Trimble was gathering its allotted data whilst we were joined just below the summit by two of Ian’s sheep dogs.

Ian Jerman at the summit of Moel y Lump

Afterward Ian drove us back down the hill and through his farmyard and down the continuation of a track toward my onward route.  I’d spent about 40 minutes in Ian’s company and he was extremely generous with his time and imparting knowledge of the hill.

I waved my goodbye’s to Ian as he headed back up the track toward his farm leaving me to slowly plod up steepening ground toward the edge of a small wood, which when followed upward would take me to the first bwlch survey of the day.  This bwlch connected with my third hill of the day and another which is unnamed on contemporary Ordnance Survey maps and one which is positioned just above the old farmhouse of Fachir.

Assessing the area of the bwlch from a number of directions I eventually chose the spot for the Trimble and stood back as it gathered data, enjoying the quietness of the scene as a westerly cloud bank edged ever nearer.  This was commented on with Ian whilst on top of Moel y Lump and I wondered if it heralded an unwelcome spell of rain.  Thankfully when it did arrive it was no more than 30 minutes of breeze-blown drizzle and a quick shower.  But before this I still had more summits to visit and the next one was placed above Fachir.

Gathering data at the bwlch of Pt. 275.1m

Rising ground led me to the next summit and as the Trimble gathered its allotted data I stood as the grey cloud heralding the incoming rain edged ever closer, and waited for the customary five minutes of data to be stored whilst munching on a boiled egg.

Gathering data at the summit of Pt. 275.1m

I’d been told by Ian that Fachir is no longer occupied but after the summit survey was finished and the equipment packed away I made my way down to its front door.  Having knocked and received no reply I continued down its access track to the bwlch that connects with Pen y Gaer.  I’d surveyed the summit of this hill with Mark Trengove in January 2015 and it was now good to do likewise with its bwlch.  LIDAR analysis shows that the track heading over the bwlch is elevated and that a natural bwlch still exists on its eastern side.  The elevation of the track was easily confirmed by eye as I approached it, and the area of the natural bwlch could also be distinguished and followed as it headed up over grazing fields to the point where I now stood.  I took two data sets, with each only a few metres apart.  During this the first breeze-blown flecks of drizzled rain fell from what was now a grey sky.

Gathering data at the bwlch of Pen y Gaer

Leaving the bwlch I headed up the continuation of the track and joined a footpath leading toward my next and fourth summit of the day.  The natural high point of this hill is on the southern side of a raised hedge which is a field boundary.  As I set up the Trimble the drizzle quickly progressed to rain.  I stood beside the hedge as data were gathered and stored, expecting to get quite wet, but thankfully the rain soon relented.

Gathering data at the summit of Field Above The House

I wanted to call at Penyffridd to make place-name enquiries; this farm is just below the summit of the hill I had just surveyed.  Descending a couple of fields took me down to the farm house where I met Gareth Jones and his daughter Katie.  Having explained my interest in hill and field names Gareth and I happily discussed the merits of the name he knows the high field as; Field Above The House.  The conversation progressed to other subjects and after ten minutes or so he asked if I wanted a drink.  Soon afterward I was sitting in his conservatory with nibbles prepared by his wife; Glenys, who also served up a large mug of very welcome tea.  I spent about an hour in the company of Gareth, chatting and laughing until the cake that was then served filled me up and I joked that if I didn’t leave soon I’d be getting back to my car when it was dark.

Gareth Jones outside Penyffridd

Over the years that I have made place-name enquiries the farming community have proved wonderfully hospitable and ever generous with their time, being only too willing to impart the knowledge of their local land to a complete stranger.  Gareth and Glenys were no different and I left having thanked them for the tea and cake and their hospitality.

The access track to Penyffridd took me down to a lane which would take me toward the last four summits of the day.  I had been with Gareth so long that the grey sky that had deposited its rain had been replaced by afternoon sunshine and lightening skies.

I called at Manor Farm on my way to the next hill, unfortunately no one was in.  My route now led through an access gate up a long field as the lowering sun cast accentuated colour across the land.  This field as many others visited on the walk is used for grazing sheep, and as I walked up it they gathered in an inquisitive line slowly approaching until they realised I had no feed and then wandered away.  The grid reference produced by LIDAR analysis led me to the high point and soon the Trimble was set-up gathering data.

Gathering data at the summit of Pt. 218.8m (SO 122 978)

This hill and the next are two that will be confirmed as deleted subs, with the following hill given as a part of Henfaes Common on the Tithe map.  To get from one summit to the other involved gates, public footpaths, a quiet wander through a field grazed by cattle until the small open wooded summit was reached.  I was nearing the end of the day’s journey but still had two summits to visit beyond this one.  The summit of this hill is positioned below mature trees and the Trimble struggled to achieve the 0.1m accuracy level before data should be logged.  I spent a long time enjoying the small open wooded summit area.  Setting the Trimble up to gather data on four separate occasions, closing down on each as the accuracy level was not obtained and eventually pressing ‘Log’ just to see what would happen, not surprisingly it screeched and closed itself down after two seconds of data were gathered.  I’ll process this just to compare its position and height against that produced by LIDAR.

The western ridge of this hill glinted green against the late afternoon sunshine as I left the hill.  Following the ridge downward I headed toward where the map indicates a public footpath follows the edge of a narrow wooded area.  This proved a delight as an old earthen track amongst open trees led down to a stream, this was at a contrast to the openness on each side where greened grazing fields shone.

The western ridge of Henfaes Common

The continuation of the track led toward a rising field and this in time took me up to the summit of the penultimate hill of the day, with the upper field named on the Tithe map as Cow Pasture.  Today the field was full of sheep and they inquisitively approached as the Trimble was being set-up and then conveniently headed away as it was gathering data.

Surveying companions at the summit of Cow Pasture

As I sat on the grass below the Trimble I examined the map.  I had a chose; either follow a footpath to the edge of Coed y Brain which was directly opposite across two grazing fields and head from there toward Red House Farm, or walk directly to the eastern edge of Coed y Brain and up the opposing hillside to visit the summit of Crasty Frain, which when height was regained would give an easier route back to my car, I opted for the latter.

Packing the Trimble away I headed down the field and crossed a fence in to the opposing grazing field and slowly plodded uphill to the track which constituted the public footpath following the edge of Coed y Brain.  Cattle lay in the late afternoon sunshine in an adjacent field whilst a tractor worked another.  Just one summit remained between me and the car and this had previously been Trimbled.

Cow Pasture from the ascent toward Crasty Frain

It proved a slow plod uphill to gain the summit of Crasty Frain, which was the first I had visited after the five mile keep local restriction was lifted in Wales a number of weeks ago.  It was now bathed in afternoon light and except for the piercing cry of a circling overhead buzzard, all was quiet.

The summit of Crasty Frain

From its high point I looked out at part of the day’s route, it had proved an excellent circular walk with lots of variety.  All that was now left was a wander down the adjacent field to the gate which I had used on my previous visit to then access the hill.  The gate led to the narrow lane I had started to walk up earlier in the day, and my car was parked just a couple of minutes’ walk away.  The walk had taken 8 hours 40 minutes with eleven data sets taken and tea and cake enjoyed! 


Survey Result:


Sixteen Acres (significant name change) 
 
Summit Height:  219.2m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision)

Summit Grid Reference:  SO 12005 98756 (Trimble GeoXH 6000)

Bwlch Height:  199.1m (LIDAR)

Bwlch Grid Reference:  SO 11953 98547 (LIDAR)

Drop:  20.1m (Trimble GeoXH 6000 summit and LIDAR bwlch) (200m Sub-Twmpau addition)

Dominance:  9.15% (Trimble GeoXH 6000 summit and LIDAR bwlch)





  
Summit Height:  276.3m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 12003 99753 (Trimble GeoXH 6000)

Bwlch Height:  c 221m (interpolation)

Bwlch Grid Reference:  SO 11982 00152 (interpolation)

Drop:  c 55m (Trimble GeoXH 6000 summit and interpolated bwlch)

Dominance:  20.01% (Trimble GeoXH 6000 summit and interpolated bwlch)





Pt. 275.1m
  
Summit Height:  275.1m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SO 13195 99523

Bwlch Height:  241.3m (converted to OSGM15)

Bwlch Grid Reference:  SO 12737 99457

Drop:  33.8m

Dominance:  12.28%





Pen y Gaer  

Summit Height:  300.0m (converted to OSGM15, from previous Trimble GeoXH 6000 survey) (200m Twmpau reclassified to Trichant)

Summit Grid Reference:  SO 13997 97677 (from previous Trimble GeoXH 6000 survey)

Bwlch Height:  214.8m (converted to OSGM15)

Bwlch Grid Reference:  SO 13170 99222

Drop:  85.2m

Dominance:  28.40%





Field Above The House (significant name change) 
 
Summit Height:  264.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 13508 99039 (Trimble GeoXH 6000) (summit relocation confirmed)

Bwlch Height:  220.0m (LIDAR)

Bwlch Grid Reference:  SO 13331 98643 (LIDAR)

Drop:  44.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  16.93% (Trimble GeoXH 6000 summit and LIDAR bwlch)





Pt. 218.8m 
 
Summit Height:  218.8m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision)

Summit Grid Reference:  SO 12216 97806 (Trimble GeoXH 6000)

Bwlch Height:  205.3m (LIDAR)

Bwlch Grid Reference:  SO 12899 97950 (LIDAR)

Drop:  13.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) (200m Sub-Twmpau deletion)

Dominance:  6.17% (Trimble GeoXH 6000 summit and LIDAR bwlch)





 
Summit Height:  215.2m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 12003 97409 (Trimble GeoXH 6000)

Bwlch Height:  198.8m (LIDAR)

Bwlch Grid Reference:  SO 12171 97587 (LIDAR)

Drop:  16.4m (Trimble GeoXH 6000 summit and LIDAR bwlch) (200m Sub-Twmpau deletion)

Dominance:  7.62% (Trimble GeoXH 6000 summit and LIDAR bwlch)






Summit Height:  215.5m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision)

Summit Grid Reference:  SO 11094 97769 (Trimble GeoXH 6000)

Bwlch Height:  190.2m (LIDAR)

Bwlch Grid Reference:  SO 11043 97985 (LIDAR)

Drop:  25.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  11.72% (Trimble GeoXH 6000 summit and LIDAR bwlch)





 
Summit Height:  256.3m (converted to OSGM15, from previous Trimble GeoXH 6000 survey) (significant height revision)

Summit Grid Reference:  SO 10995 98318 (from previous Trimble GeoXH 6000 survey) (summit relocation confirmed)

Bwlch Height:  226.1m (LIDAR)

Bwlch Grid Reference:  SO 10787 98754 (LIDAR)

Drop:  30.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) (200m Sub-Twmpau reclassified to 200m Twmpau)

Dominance:  11.79% (Trimble GeoXH 6000 summit and LIDAR bwlch)