Tuesday, 25 September 2018

Mapping Mountains – Hill Reclassifications – 100m Twmpau


Pt. 184.3m (SN 202 110) – 100m Twmpau reclassified to 100m Sub-Twmpau

There has been a reclassification to the 100m Twmpau due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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.

Prior to LIDAR analysis this hill was listed with an estimated c 30m of drop based on the 184m summit height given to a triangulation pillar on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated bwlch height of c 154m based on interpolation of 5m bwlch contouring between 150m – 155m on the Ordnance Survey 1:25,000 Explorer map.

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

As I do not know an appropriate name for this hill it is being listed by the point (Pt. 184.3m) notation, with its previously listed name of Castle Ely Hill being an invention and now considered inappropriate and the Tithe map only giving a generic name of Field.  The hill is adjoined to the Brandy Hill group of hills, which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned with the coast to its south and the B 4314 road to its north-east, and has the small community of Rhos-goch (Red Roses) towards its north.

If wanting to visit the hill permission to do so should be sought as it is not a part of designated open access land, for those wishing to do so the nearest public right of way is on a lane / track to the east of the summit.

The reclassification of this hill to 100m Sub-Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips.  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 Pt. 184.3m (SN 20227 11011)

The 1m and 2m DTM LIDAR analysis gives the hill the following details:


Name:  Pt. 184.3m

Summit Height:  184.3m

Summit Grid Reference:  SN 20227 11011

Bwlch Height:  154.7m

Bwlch Grid Reference:  SN 20492 11533

Drop:  29.5m


Therefore, the 184.3m 2m DTM LIDAR analysis for the summit position at SN 20227 11011 and the 154.7m 1m DTM LIDAR analysis for the bwlch position at SN 20492 11533 gives this hill 29.5m of drop, which is not sufficient for its continued 100m Twmpau status.


The full details for the hill are:

Group:  Brandy Hill

Name:  Pt. 184.3m

OS 1:50,000 map:  158

Summit Height:  184.3m (2m DTM LIDAR)

Summit Grid Reference:  SN 20227 11011 (2m DTM LIDAR)

Bwlch Height:  154.7m (1m DTM LIDAR)

Bwlch Grid Reference:  SN 20492 11533 (1m DTM LIDAR)

Drop:  29.5m (LIDAR)


Myrddyn Phillips (September 2018)




Monday, 24 September 2018

Mapping Mountains – Significant Name Changes – The Fours


Cefn Fron Hill (SO 165 838)

There has been a Significant Name Change to a hill that is listed in The Fours, with this being announced when the 2nd edition of The Fours was published by Mapping Mountains Publications on the 24th April 2018.

The criteria for the list that this name change applies to are:

The Fours – English hills at or above 400m and below 500m in height that have 30m minimum drop.  Accompanying the main list of The Fours are three categories of sub hills, with this hill listed as a 400m Sub-Four.  The criteria for 400m Sub-Four status are all English 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, with the 1st edition of the list having been published by Europeaklist in December 2013 and by Haroldstreet in January 2014, with the 2nd edition of the list published by Mapping Mountains Publications and by Haroldstreet on the 24th April 2018.

The hill is situated in the Welsh Borders and is placed in Region 38, Section 38A: Shropshire, with its Cardinal Hill being Cilfaesty (SO 128 840).  The hill is positioned with the B 4355 road to its south and the B 4368 road to its north, and has the small community of Felindre towards the south and the town of Trefyclo (Knighton) towards the south-east.

The hill was not included in the listing that is now known as The Fours when originally compiled as it did not at that stage meet the criteria used for the accompanying sub list, this sub list has now been standardised and the hill was listed by its contemporary Ordnance Survey map composition of Cefn Vron Hill in 1st edition of The Fours when the list was published by Europeaklist in December 2013. 

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

Where hill names are documented on contemporary Ordnance Survey maps in an anglicised form and the name is proven to have originated from a Welsh form, it is accepted practice that the name should be presented in its original form, and the anglicised form of Cefn Vron Hill in such an example.

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

Therefore, the name composition this hill is now listed by in The Fours is Cefn Fron Hill and this follows the standard and accepted practice for using the Welsh form where a hill name appears as an anglicised form on contemporary Ordnance Survey maps.  


The full details for the hill are:

Cardinal Hill:  Cilfaesty

Name:  Cefn Fron Hill

Previously Listed Name:  Cefn Vron Hill 

Summit Height:  415.5m (LIDAR)

OS 1:50,000 map:  136

Summit Grid Reference:  SO 16547 83808
  
Drop:  24.0m (LIDAR)


Myrddyn Phillips and Aled Williams (September 2018)







Sunday, 23 September 2018

Mapping Mountains – Hill Reclassifications – 100m Twmpau


White Park (SN 158 091) – 100m Sub-Twmpau reclassified to 100m Twmpau

There has been confirmation of a reclassification to the 100m Twmpau due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m 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.

When the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill appeared in the accompanying Hills to be surveyed sub list as it did not meet the criteria then used for the main P30 list; however this sub list has now been standardised and interpolated heights also included in the main P30 and the accompanying sub list.

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

When this list was standardised and interpolated heights also included this hill was listed with an estimated c 29m of drop, based on the 137m height given to a triangulation pillar on the summit area and an estimated bwlch height of c 108m based on interpolation of 5m bwlch contouring between 105m – 110m on the Ordnance Survey 1:25,000 Explorer map.  The drop value was re-assessed prior to LIDAR analysis and a tentative estimate of c 30m then given.

The name of the bounded land where the summit of this hill is situated is White Park, and this was derived from the Tithe map.  The hill is adjoined to the Brandy Hill group of hills, which are situated in the south-western part of Mid and West Wales (Region B, Sub-Region B4), and is positioned between the coast to its south and the A 47 road to its north, and has the small community of Ludchurch to its north-west.

If wanting to visit the hill permission to do so should be sought as it is not a part of designated open access land and has no rights of way on it, although a permissive path does cross the hill to the south of its summit.

The confirmation of the addition of White Park to 100m Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips.  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 the bwlch of White Park

LIDAR image of the summit of White Park

The 2m DTM LIDAR analysis gives the hill the following details:


Name:  White Park

Summit Height:  138.1m

Summit Grid Reference:  SN 15867 09111

Bwlch Height:  107.1m

Bwlch Grid Reference:  SN 15723 09669

Drop:  31.0m


Therefore, the 138.1m LIDAR analysis for the summit position at SN 15867 09111 and the 107.1m LIDAR analysis for the bwlch position at SN 15723 09669 gives this hill 31.0m of drop, which confirms its addition to 100m Twmpau status.


LIDAR image of White Park

The full details for the hill are:

Group:  Brandy Hill

Name:  White Park

OS 1:50,000 map:  158

Summit Height:  138.1m (LIDAR)

Summit Grid Reference:  SN 15867 09111 (LIDAR)

Bwlch Height:  107.1m (LIDAR)

Bwlch Grid Reference:  SN 15723 09669 (LIDAR)

Drop:  31.0m (LIDAR)


Myrddyn Phillips (September 2018)









Saturday, 22 September 2018

Mapping Mountains – Trimble Surveys – Bannau Brycheiniog


30.06.18  Waun Rydd (SO 062 206 [only bwlch surveyed SO 031 205]), Fan y Big (SO 036 206), Gwaun Cerrig Llwydion (SO 041 196) and Craig Gwrelyg (SO 055 203)

Gwaun Cerrig Llwydion (SO 041 196)

With the weather set fine I was spurned in to surveying action and headed south to the sublime peaks of Bannau Brycheiniog.  Although I had three hills and another’s bwlch planned to survey it was Fan y Big above all others that drew my attention.  This hill is currently listed as a Simm and Hewitt, with 600m and 2,000ft their respective qualifying heights and 30m their minimum drop, with both lists authored by Alan Dawson.

Fan y Big is positioned on the main Bannau Brycheiniog ridge and is situated east of Cribyn and to the west of Waun Rydd, with both of these hills being higher, however Fan y Big has an appealing summit with great sweeping drops in to Cwm Cynwyn and Cwm Oergwm and a narrowing grassy north ridge that leads direct to its summit. 

Its current status as both a Simm and Hewitt is border line as it is listed with 30m of drop, which is the minimum required for these classifications, with this drop value based on the 719m summit spot height on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and the 689m bwlch spot height on the Ordnance Survey Interactive Coverage Map hosted on the Geograph website.

Although this hill has always been a marginal P30, to my knowledge it was John Kirk who first petitioned for this hill to be accurately surveyed as he doubted its P30 status, his doubts seemed to have been proven correct when I asked Aled to analysis this hill with LIDAR, resulting in a 28.2m drop, which is insufficient for both Simm and Hewitt status, Alan was notified of Aled’s LIDAR analysis and hoped to visit the hill and survey it with his Leica RX1250 later in the year, this was in 2017, but the opportunity to do so did not arise.

I then reclassified this hill to a 700m Sub-Twmpau based on the result produced by Aled’s LIDAR analysis and waited for Alan to venture south on one of his Welsh surveying bonanzas.  No more was heard about Fan y Big until Tony Jenkins posted on the Tump forum a link to my 700m Twmpau Hill Reclassification post on Mapping Mountains, and this stirred me in to action, but with the weather predicted to be another warm day I needed to get an early start if I hoped to survey this and adjacent hills before the hot conditions took their toll.

I set my alarm for 3.00am and was parked on the southern side of the Beacons and walking by 5.45am.  The sky was clear blue and early morning freshness pervaded the land which was accentuated by a light breeze, bringing comfort to those of us who suffer when the hill going becomes extremely warm.

Early morning start and the way to the hill

Even at this early hour there were people heading for the hill, and more appeared as I made good progress up the contouring path beside the Taf Fechan Forest, which led on to open hillside and gained height above the Upper Neuadd Reservoir.  I had contemplated visiting Cribyn using a path from its connecting bwlch with Fan y Big, but decided that this hill could wait for another day.

Pen y Fan

At just before 7.00am the Trimble was positioned at this first bwlch which is the critical one for Waun Rydd and data being gathered, all those I had seen on the path were now heading for Cribyn and Pen y Fan and land around the bwlch was remarkably quiet for the Beacons at a weekend.  Just as the last of the 360 datum points were collected a mountain biker appeared pushing his bike up toward the bwlch, the Trimble was closed down, packed away and I was heading up the steepening path toward the summit of Fan y Big before he reached the top of the path leading to the bwlch.

Gathering data at the critical bwlch of Waun Rydd

Fan y Big has a marvellous vantage point with the higher Beacons to its west and the continuation of the main ridge to its east, its high point is easily identifiable and consists of a small grassed hummock beside the eroded path that continues down its northern ridge.  As I set the Trimble up with its internal antenna aligned with the high point of the hill the sky still shone blue but to the east Mynyddoedd Duon were battling with early morning mist and a northerly mist bank quickly headed south toward the hill.

The Trimble set-up position at the summit of Fan y Big

Mist banks over Mynyddoedd Duon

I decided that the importance of the survey constituted two ten minute data sets from the summit and also from the bwlch, and as the first summit survey neared completion the mist rolled in up each cwm to the immediate east and west.  I quickly closed the Trimble down and reactivated it for its second ten minute data set, as it beeped away collecting its individual data appoints I was treated to a beautiful scene as mist enveloped the land below and the sun from behind created a Brocken spectre on the mist below, it had been many years since I had last experienced such a treat on a hill and I stood and stared and enjoyed and savoured for many a minute as the mist forever changed and the sun disappeared to reappear again and cast another Brocken spectre below.

Gathering data at the summit of Fan y Big

Brocken spectre from the summit of Fan y Big

By the time I closed the Trimble down I felt content with my lot in the world and headed off following the ridge toward the next important survey; the critical bwlch of Fan y Big.  This proved easy to identify even without the ten figure grid reference produced by LIDAR analysis directing me to its critical point.  I again took two ten minute data sets and sat sheltered from the increasing breeze which whipped mist up from the cwm below across the ridge in delicate and fast moving formations.

Gathering data at the critical bwlch of Fan y Big

Two hills remained to be surveyed, the first of which was Gwaun Cerrig Llwydion which only just misses Uchaf status according to LIDAR analysis and a basic levelling survey I conducted many a year ago.  I left the bwlch of Fan y Big and gained height in to the freshening mist and emerged on the summit as the heat of the morning started to burn the mist away.  The summit of this hill lay close to the eroded path and another data set was gathered.

Gathering data at the summit of Gwaun Cerrig Llwydion

The bwlch of Gwaun Cerrig Llwydion is an utter contrast to that of Fan y Big and lies in a morass of flatness with dry bog, tussock and a wildness to it, I was thankful that it was free of mist and if not for the ten figure grid reference produced by LIDAR which directed me to its critical point, I could easily have been 50 metres away with my positioning for the Trimble based purely on my eye.  As the Trimble gathered its allotted data I sat on a rock and luxuriated myself in the morning sun, it was still only 9.15am and only two surveys remained.

Gathering data at the critical bwlch of Gwaun Cerrig Llwydion

Leaving the bwlch I re-joined the eroded ridge path as it sped along above the upper reaches of Cwm Oergwm toward the final summit of the day which is the high point of Craig Gwrelyg, which is listed as an Uchaf and Pellennig hill.

Gathering data at the summit of Craig Gwrelyg

As the Trimble gathered its last summit data set of the day a murky cloud bank remained to the west hiding Fan y Big and its higher neighbours, and yet the part of the ridge I was on was now bathed in sunshine which over the next 30 minutes gradually increased in strength.

All that remained was the bwlch survey for Craig Gwrelyg and again the ten figure grid reference produced by LIDAR took me down to it.  Whilst waiting for the Trimble to achieve its 0.1m accuracy level before data should be logged I chatted with a group of walkers who were out on a navigation course and asked their opinion of where this critical bwlch lay, I had conflicting opinions given me with one deciding it was placed firmly on the upward part of the hill to hill traverse!

Gathering data at the critical bwlch of Craig Gwrelyg

As I packed the Trimble away the heat had increased, but all I now faced was downhill and although the first beads of sweat were now on my brow, I set off on the path following the escarpment edge above Blaen y Glyn with an added momentum, happy in the knowledge that all planned surveys were complete and that Fan y Big had finally been accurately surveyed.

The descent route over Craig y Fan Ddu


Survey Result:


Waun Rydd 

Bwlch Height:  599.5m (converted to OSGM15)

Bwlch Grid Reference:  SO 03161 20517

Drop:  169.7m






Fan y Big

Summit Height:  716.7m (converted to OSGM15, average of three summit surveys [two on 30.06.18 and the third on 21.08.18]) (significant height revision)

Summit Grid Reference:  SO 03652 20658

Bwlch Height:  688.2m (converted to OSGM15, average of two bwlch surveys)

Bwlch Grid Reference:  SO 03773 19876

Drop:  28.5m (700m Twmpau reclassified to 700m Sub-Twmpau confirmed) (Hewitt deletion) (Simm reclassified to Subsimm)

Dominance:  3.98%

For details on the second summit survey of Fan y Big





Gwaun Cerrig Llwydion

Summit Height:  729.2m (converted to OSGM15)

Summit Grid Reference:  SO 04140 19665

Bwlch Height:  715.1m (converted to OSGM15)

Bwlch Grid Reference:  SO 04562 19624

Drop:  14.0m (500m Sub-Uchaf status confirmed)

Dominance:  1.92%





Craig Gwrelyg (significant name change)

Summit Height:  753.9m (converted to OSGM15)

Summit Grid Reference:  SO 05521 20383

Bwlch Height:  735.1m (converted to OSGM15)

Bwlch Grid Reference:  SO 05763 20570

Drop:  18.9m (Uchaf and Pellennig status confirmed)

Dominance:  2.50%






Friday, 21 September 2018

Mapping Mountains – Hill Reclassifications – The Fours


Pt. 405m (SK 073 699) – 400m Sub-Four deletion

There has been a deletion from the listing of The Fours due to analysis of data on the OS Maps website, which is the recent replacement for OS Get-a-map.  The Fours is the title for the list of 400m hills of England and takes in all English hills at or above 400m and below 500m in height that have a minimum 30m of drop, the list is co-authored by Myrddyn Phillips and Aled Williams and the 2nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24th April 2018.

Accompanying the main list of The Fours are three categories of sub hills, with this hill being deleted from the 400m Sub-Fours.  The criteria for 400m Sub-Four status are all English hills at or above 400m and below 500m in height that have 20m or more and below 30m of drop. 
 
Prior to analysis of data on OS Maps this hill was listed with c 22m of drop based on the 405m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated col height of c 383m based on col contouring at 5m intervals and presumed between 380m – 385m on the 1:25,000 Explorer maps.  However, as the contours at this hill’s col are on land that is a part of the Hillhead Quarry the 1:50,000 and 1:25,000 maps do not show continuous contouring; as a result the estimated col height was considered debatable.

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

As the authors do not know an individual name for this hill it appeared listed under the point (Pt. 405m) notation and it is situated in the Southern Pennines and is placed in Region 36, with its Cardinal Hill being Axe Edge (SK 035 706).  The hill is positioned above the A 515 road which is to its north-east and has the town of Buxton to its north north-west.

As the hill is not a part of designated open access land permission to visit should be sought, for those wishing to do so the easiest access may be from a public footpath that follows the course of a dismantled railway to the hill’s north and east.

The deletion of Pt. 405m from 400m Sub-Four status is due to the analysis of data on the OS Maps website.  This mapping gives contour intervals at 5m which has enabled the height of the col to be narrowed down when compared to the lack of continuous contours on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps.  Therefore with a 405m summit spot height on the Ordnance Survey 1:25,000 Explorer map and an estimated col height of c 386m, based on interpolation of col contouring on OS Maps between 385m – 390m, this hill is now listed with c 19m of drop, which is insufficient for its continued inclusion as a 400m Sub-Four.

 
Extract from OS Maps

The full details for the hill are:

Cardinal Hill:  Axe Edge

Summit Height:  405m

Name:  Pt. 405m

OS 1:50,000 map:  119

Summit Grid Reference:  SK 073 699

Drop:  c 19m


For the additions, deletions and reclassifications to The Fours reported on Mapping Mountains since the December 2013 publication of the list by Europeaklist please consult the following Change Registers:










Myrddyn Phillips and Aled Williams (September 2018)