Tuesday, 31 January 2017

Mapping Mountains – Hill Reclassifications – Yr Uchafion


Cefn Onneu (SO 171 156) - Uchaf reclassified to 500m Sub-Uchaf

There has been a reclassification to the listing of Yr Uchafion instigated from analysis of LIDAR data by Aled Williams.  Yr Uchafion is the draft title for a list of the Welsh 500m P15s that takes in all hills in Wales at or above 500m that have a minimum drop of 15m, the list is a joint compilation with Aled Williams.  Details relating to this list were published on the Mapping Mountains site in November 2015.

The listing of Yr Uchafion includes three sub lists; the 500m Sub-Uchaf, 490m Sub-Uchaf and the Double Sub-Uchaf category.  The reclassification of this hill is from Uchaf to 500m Sub-Uchaf, with the criteria for this sub category being all Welsh hills at or above 500m in height that have 14m or more and below 15m of drop.

The hill is situated in the Bannau Brycheiniog (Brecon Beacons) group of hills with its Cardinal Hill being Pen y Fan (SO 012 215) and is placed in the Region of South Wales (C-2).  The hill is situated between the villages of Llangynidr to its north north-west, Cendl (Beaufort) to its south and Llangatwg to its east north-east.

The hill was listed with c 15m of drop which is the minimum drop value for inclusion as an Uchaf, with a c 530m summit based on a small uppermost 530m ring contour on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and an estimated bwlch height of c 515m based on bwlch contouring between 510m – 520m.

The name of the hill is Cefn Onneu and it can be easily accessed from its west as the B 4560 passes within 0.7km of its summit, and its reclassification from an Uchaf to a 500m Sub-Uchaf is due to the analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data gives the hill the following details:


Cefn Onneu

Summit Height:  530.0m

Summit Grid Reference:  SO 17112 15692

Bwlch Height:  515.6m

Bwlch Grid Reference:  SO 16549 15819

Drop:  14.4m


Therefore, the 530.0m LIDAR data produced for the summit position at SO 17112 15692 and the 515.6m LIDAR data produced for the bwlch position at SO 16549 15819 gives this hill 14.4m of drop which is insufficient for it to retain its Uchaf status as its drop is below the required minimum of 15m.


The full details for the hill are:

Cardinal Hill:  Pen y Fan

Summit Height:  530.0m (LIDAR data)

Name:  Cefn Onneu

OS 1:50,000 map:  161

Summit Grid Reference:  SO 17112 15692 
  
Drop:  14.4m (LIDAR data)


This now brings the overall total for Yr Uchafion / The Welsh 500m P15s to 630 hills and the overall total for the 500m Sub-Uchaf category to 25.

The additions, reclassifications and deletions to Yr Uchafion / The Welsh 500m P15s reported on Mapping Mountains are ills of wales as follows:



UCHAF ADDITIONS









UCHAF RECLASSIFICATIONS





Cefn Onneu (LIDAR data) (SO 171 156) Uchaf reclassified to 500m Sub-Uchaf with 14.4m of drop




UCHAF DELETIONS






Myrddyn Phillips and Aled Williams (January 2017)



Monday, 30 January 2017

Y Pedwarau – The 400m Hills of Wales


Introduction

Y Pedwarau – The 400m Hills of Wales





Publication History

Y Pedwarau are the Welsh hills at or above 400m and below 500m in height that have a minimum drop of 30m.  The list’s initial compilation was completed in November 2002 and entitled The 400m Peaks of Wales and was first published on 19th December 2002 on the RHB Yahoo Group file database along with the equivalent English and Manx hills, with the file entitled the 400m hills of England, Isle of Man and Wales, this file was uploaded by Rob Woodall who later augmented data from Clem Clements into the database.

The listing was re-evaluated and later published on 22nd October 2004 on Geoff Crowder’s v-g.me website and entitled The Welsh 400 Metre Peaks, coinciding with Geoff’s publication the list was also published by Mike Grant on his 5everdene website.     

The master hand written list was maintained by Myrddyn Phillips with occasional updates appearing on the v-g.me website, with the original publication on the RHB Yahoo Group file database later being duplicated en masse by Mark Jackson without prior consultation with, or even notification to the author, with these data forming the equivalent part of the Tumps and with this act resulting in years of undue data divergence that is ongoing.

The list was next fully re-evaluated for publication by Europeaklist on 23rd May 2013, with the compilation now entitled Y Pedwarau and leading the way to the list becoming co-authored with Aled Williams.  The listing of Y Pedwarau was later published on 6th January 2014 by Phil Newby on his Haroldstreet website, and all future updates to the list have been catalogued on the Mapping Mountains site.



Y Pedwarau on Mapping Mountains

Since Y Pedwarau was published by Haroldstreet there has been a number of reclassifications to the list, all of these have been reported on Mapping Mountains, but few have found their way into the Haroldstreet publication. 

With the advent of independent surveyors and the accuracy of LIDAR data it is becoming increasingly more difficult to keep a list up-to-date if it is hosted on another person’s website, and for these reasons it has become evident that Mapping Mountains should host the master Y Pedwarau list.

Y Pedwarau will be published on Mapping Mountains in hill group format on an ad hoc basis.  Therefore when each hill group has been compiled with all relevant detail it will be uploaded to the Master List which will be available in Google Doc format on the Mapping Mountains site.  As the list will be published by group format and therefore not initially in its entirety, it will take approximately a year until the complete up-to-date list is available on the Mapping Mountains site.

As well as the main Y Pedwarau list being published the Mapping Mountains publication will also have five Sub lists accompanying the main P30 list, these Sub lists are:


500m Sub-Pedwarau - Welsh hills at or above 500m and below 510m in height with 30m minimum drop.

500m Double Sub-Pedwarau - Welsh hills at or above 500m and below 510m in height with 20m or more and below 30m of drop.

400m Sub-Pedwarau - Welsh hills at or above 400m and below 500m in height with 20m or more and below 30m of drop.

390m Sub-Pedwarau - Welsh hills at or above 390m and below 400m in height with 30m minimum drop.

390m Double Sub-Pedwarau - Welsh hills at or above 390m and below 400m in height with 20m or more and below 30m of drop.


To the knowledge of the authors this is the first time that a higher tier Sub category has accompanied a list that includes the standard lower tier Sub category.  In this instance the higher tier is the 500m Sub-Pedwarau and 500m Double Sub-Pedwarau and the lower tier is the 390m Sub-Pedwarau and the 390m Double Sub-Pedwarau.  One without the other is being inconsistent, that is now rectified for Y Pedwarau.






The list consists of the following:

Group:  Each hill appears under their Group, this is the group / range that the hill is a part of.  For example; Crimpiau (SH 733 595) is a part of the hill group known as the Carneddau.  The Groups are arranged from north to south on a west to east orientation.

Name:  This is considered the most appropriate name for the hill with respect to the information available to the authors.  Sometimes the name used does not correspond to current Ordnance Survey map spelling and composition or the name may not appear on any map.  Where no appropriate name has been discovered for the hill from any source, the Point (for example; Pt. 478m) notation is used rather than making up a name that has no local or historical evidence of use.

Summit Height (m):  This gives the map height in metres of the hill above Ordnance Datum Newlyn (ODN), often referred to as sea level.  Where a height is quoted to a decimal place it implies that the hill has been surveyed by GPS / GNSS receiver or obtained from analysis of LIDAR data (these heights may not match current Ordnance Survey map heights).  Where a ‘c’ (circa) appears preceding the height it means there is no known spot height available and the height has been estimated from contour interpolation.  All heights are converted to OSGM15.

Region:  There are three Regions in Wales; North Wales, Mid and West Wales, and South Wales.  The Regional split of Wales used in this list has been documented on the Mapping Mountains site.

Sub-Region:  The three Regions of Wales are further split up into Sub-Regions, this sub-division takes in the topography and geography of each Region.

1:50,000 Map:  This column gives the number or numbers of the 1:50,000 Ordnance Survey Landranger map that the summit of the hill appears on.

1:25,000 Map:  This column gives the number or numbers of the 1:25,000 Ordnance Survey Explorer map that the summit of the hill appears on.

Cardinal Hill:  Each hill group can be split into Cardinal Hills; these are the hills of most significant height or drop/prominence.  In affect these are the ‘Grouped Parent Hills’ to any individual hill that is listed.  Since publication of Y Pedwarau by Europeaklist in May 2013 the Cardinal Hills for Wales have been fully re-evaluated and updated accordingly.

Summit Grid Reference:  This is the ten figure grid reference (10FGR) for the summit of the hill.  This has either been produced by an accurate survey, a map spot height or when neither is available by a centralised position in an uppermost contour ring.  When the accurate survey has been conducted independent of the Ordnance Survey a (S) for ‘survey’ will appear adjacent to the 10FGR, a (L) if the 10FGR has been obtained from analysis of ‘LIDAR’ data, a (TP) if the 10FGR is taken to a ‘trig pillar’, a (B) if the 10FGR is taken to a ‘bolt’ or a ‘block’, a (Le) if the 10FGR is taken to the position of a ‘levelled’ height on old maps, a (HH) if the 10FGR is taken from a ‘hand-held’ GPS unit, a (SH) if the 10FGR is taken to a ‘spot height’ either on current or old maps and an (I) if the summit position has been ‘interpolated’ from contours.

Drop (m):  This column details the prominence of the hill; this is commonly referred to as ‘drop’ or ‘reascent’.  The drop is the height difference between the summit and connecting bwlch to the higher parent peak along the watershed.  The letter ‘c’ before the drop figure signifies there is no spot height or surveyed height known for either summit or more usually, the bwlch, therefore a part of the drop figure has been estimated from contour interpolation.

Notes:  This column gives details relating to the hill.



Thanks are given to the people who submit 10 figure grid references to the Database of British and Irish Hills (DoBIH) and for DoBIH making these available for public use.





To access the Y Pedwarau Change Registers:










Myrddyn Phillips and Aled Williams (January 2017)

Sunday, 29 January 2017

Change Register – Y Pedwarau – 390m Double Sub-Pedwarau


Change Register

Y Pedwarau – The 400m Hills of Wales

390m Double Sub-Pedwarau


Y Pedwarau are the Welsh hills at or above 400m and below 500m in height that have a minimum drop of 30m.  The list’s initial compilation was completed in November 2002 and entitled The 400m Peaks of Wales and was first published on 19th December 2002 on the RHB Yahoo Group file database along with the equivalent English and Manx hills, with the file entitled the 400m hills of England, Isle of Man and Wales, this file was uploaded by Rob Woodall who later augmented data from Clem Clements into the database.

Over subsequent years the listing now known as Y Pedwarau has been published on the v-g.me website and the 5everdene website in list format (22nd October 2004), available as a downloadable e-booklet and print-booklet version on the Europeaklist website (23rd May 2013), available as GPS Waypoints, Google mapping and online hill bagging tick lists on the Haroldstreet website (6th January 2014) and as of 30th January 2017 publication of Y Pedwarau commenced on the Mapping Mountains site.

Each publication had an accompanying sub list, but it wasn’t until the Europeaklist publication and the subsequent Haroldstreet publication that a sub list to the 390m Sub-Pedwarau was included.

The 390m Sub-Pedwarau are those hills that fail to meet the Pedwar qualification by 10m or less of height, these are the hills that are 390m or more and below 400m in height that have a minimum 30m of drop.

This 390m category of sub hill also has a category for Double Subs, these are the hills that fail to meet the Pedwar qualification by less than 10m of height and also less than 10m of drop and are below the 400m minimum height threshold, these are the hills that are 390m or more and below 400m in height that have 20m or more and below 30m of drop, they are known as the 390m Double Sub-Pedwar hills.

The 390m Double Sub-Pedwar hills first appeared as a category of hill in the December 2013 publication by Europeaklist, when this version of Y Pedwarau was published there were sixteen hills listed that met the qualification for 390m Double Sub-Pedwar status, all of these hills were identified leading up to this publication.

However, since the December 2013 Europeaklist publication all available online Ordnance Survey maps have been scrutinised and a number of other hills have been identified that meet this 390m Double Sub-Pedwar qualification, and these have appeared as updates to the list on the Mapping Mountains site.

With all updates to the list appearing on Mapping Mountains it became evident that keeping the list up-to-date if hosted on another person’s website was difficult to say the least, therefore on 30th January 2017 the Y Pedwarau list commenced publication on Mapping Mountains with five sub lists accompanying the main P30 Pedwar list.   

Since its original publication Y Pedwarau has changed greatly as the list is now co-authored with Aled Williams, and the numerical data benefits from online mapping, surveys by independent surveyors and the analysis of LIDAR data, whilst also benefiting from meticulous place-name research conducted by Aled, and it seems fitting that the list of Y Pedwarau – The 400m Hills of Wales should now benefit from a detailed Change Register to the 390m Double Sub-Pedwarau, and it is prudent for this Change Register to initially detail the changes to the list since the 2013 publication by Europeaklist.

The Change Register to Y Pedwarau – The 400m Hills of Wales – 390m Double Sub-Pedwarau appears below with the reclassifications to the list being detailed chronologically in receding order.



Change Register

Y Pedwarau – The 400m Hills of Wales

390m Double Sub-Pedwarau





Cyrnau Mawr    391.4m at SN 75154 75006

Cyrnau Mawr (SN 751 750) is the latest addition to the 390m Double Sub-Pedwar ranks

The announcement of this hill’s addition to the ranks of the 390m Double Sub-Pedwarau was made on Mapping Mountains on 02.07.16, the hill was previously not classified although it had been catalogued with c 16m of drop based on an estimated c 390m summit height and an estimated c 374m bwlch height.  Its addition is dependent upon the analysis of LIDAR data by Aled Williams, which was subsequently confirmed with a survey using the TrimbleGeoXH 6000 conducted by Myrddyn Phillips, with the LIDAR analysis giving the hill 21.6m of drop based on a 391.4m summit and a 369.8m bwlch height, and the Trimble survey giving the hill 21.6m of drop based on a 391.4m summit and a 369.8m bwlch height, with the correlation between each being excellent.  390m Double Sub-Pedwar total increases by one and confirmed as 26.





Allt y Genlli    398.9m at SN 98508 95042

The announcement of this hill’s reclassification to 390m Sub-Pedwar status was via the Mapping Mountains site on 24.05.17, the hill was previously listed as a 390m Double Sub-Pedwar with 27m of drop based on the 394m summit spot height on the Ordnance Survey 1:25,000 Explorer map and the 367m bwlch spot height on the Ordnance Survey enlarged mapping hosted on the Geograph website.  Its reclassification is dependent upon the analysis of LIDAR data by Aled Williams of it, and its southerly adjacent hill of Mynydd Garth Pwt, with the result being a swap in listed bwlch positions as the 398.9m summit height of Allt y Genlli is higher than the 397.8m summit height of Mynydd Garth Pwt, with the heights of the bylchau being 325.7m and 367.3m respectively, therefore the lower bwlch is the critical bwlch for the higher of the two hills, with these values giving Allt y Genlli 73.2m of drop which is sufficient for it to be classified as a 390m  Sub-Pedwar, and with 30.5m of drop Mynydd Garth Pwt also retains its 390m Sub-Pedwar status.  390m Double Sub-Pedwar total decreases by one and confirmed as 25.






390m Double Sub-Pedwar total confirmed as 26.




Pt. 391.9m    391.9m at SN 99803 43305  

This hill’s deletion from the ranks of 390m Double Sub-Pedwarau was announced on Mapping Mountains on the 28.01.17, the hill was not originally included in this sub category when the Y Pedwarau list was published by Europeaklist in May of 2013, and only later included through its 393m summit spot height on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 373m, which gave this hill a listed drop of c 20m.  It’s inclusion as a 390m Double Sub-Pedwar hill (see below) was reported on Mapping Mountains on the 28.02.14, and its subsequent deletion from this sub list is due to analysis of LIDAR data by Aled Williams, with the resulting details being a 391.9m summit and a 372.0m bwlch height, these values give this hill only 19.9m of drop which is not sufficient for it to retain its status as a 390m Double Sub-Pedwar hill.  390m Double Sub-Pedwar total decreases by one and confirmed as 26.





Cefn Bach    389.2m at SO 00471 38745

The northerly summit of Cefn Bach is now deleted from the ranks of 390m Double Sub-Pedwarau

The deletion of this hill from the ranks of 390m Sub-Pedwarau was announced on the Mapping Mountains site on 25.01.17.  The hill had been listed as being 391m high with c 22m of drop based on bwlch contouring between 360m – 370m with an estimated bwlch height of c 369m, and it was listed as a 390m Double Sub-Pedwar in deference to its adjacent southerly twin topped 391m map heighted hill at SO 00293 37291 which had been listed as 390m Sub-Pedwar with 55m of drop.  This southerly hill was subsequently surveyed by Myrddyn Phillips on the 18.08.15 with the Trimble GeoXH 6000, and the resulting 389.4m summit height and 54.4m bwlch height was announced on the Mapping Mountains site on 22.09.15.  However, it wasn’t until these two hills were analysed with LIDAR data by Aled Williams that the southerly of the two summits was confirmed as being 0.2m higher than its northerly neighbour, with the result of the northerly summit that was listed as a 390m Double Sub-Pedwar being only 389.2m high, which is below the required height to be classified in this sub category.  390m Double Sub-Pedwar total decreases by one and confirmed as 27.





Craig Rhiw Berfa    397.2m at SS 94593 90610  

This is the first hill to lose its 390m Double Sub-Pedwar status and it is due to the analysis of LIDAR data by Aled Williams, the announcement of this change in classification was given on the Mapping Mountains site on 24.12.16, with the resulting height details being 397.2m summit and 378.4m bwlch, giving this hill 18.8m of drop.  Craig Rhiw Berfa did not appear as a 390m Double Sub-Pedwar in the list published by Europeaklist and Haroldstreet and was only announced as being added to this classification on 28.02.14 (see below).  390m Double Sub-Pedwar total decreases by one and confirmed as 28.





Penmaen Mawr    390.4m at SH 69865 75523

Penmaen Mawr is now classified as a 390m Double Sub-Pedwar

This hill’s addition as a 390m Double Sub-Pedwar was announced on the Mapping Mountains site on 25.07.16, the hill has been extensively quarried and was once the proud owner of a 1,550ft (472m) summit spot height and a prominence of over 100m, however it is now reduced in height and prominence and its survey by Myrddyn Phillips and Aled Williams on 14.07.17 using the Trimble GeoXH 6000 had been long anticipated, with the resulting 390.4m summit height and 363.5m bwlch height sufficient for this hill to qualify as a 390m Double Sub-Pedwar with a height over 390m and a drop of 26.9m.  390m Double Sub-Pedwar total increases by one and confirmed as 29.



 

Craig Rhiw Berfa    399m at SS 94593 90610

This hill’s qualification to the 390m Double Sub-Pedwar list was announced on the Mapping Mountains site on 28.02.14, the hill joins the ranks of this sub list as it has a 399m summit spot height on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 378m based on bwlch contouring between 370m and 380m, these values give this hill c 21m of drop and was sufficient for it to be classified as a 390m Double Sub-Pedwar until its details were analysed by LIDAR data (see above).  390m Double Sub-Pedwar total increases by one and confirmed as 28.





Pt. 399m    399m at SO 02704 38530

The 390m Double Sub-Pedwar status of this hill was announced on the Mapping Mountains site on 28.02.14, and it qualifies for this classification as it has a 399m summit spot height appearing on the Ordnance Survey enlarged mapping hosted on the Geograph website and an estimated bwlch height of c 378m based on bwlch contouring between 370m – 380m, these values give this hill c 21m of drop.  390m Double Sub-Pedwar total increases by one and confirmed as 27.





Pt. 393m    393m at SN 99813 43255

This hill’s qualification to the ranks of 390m Double Sub-Pedwar was announced on Mapping Mountains on 28.02.14, and the hill qualifies for this category with c 20m of drop based on its 393m summit spot height and an estimated bwlch height of c 373m based on bwlch contouring between 370m – 380m, and this was sufficient for it to be classified as a 390m Double Sub-Pedwar until its details were analysed by LIDAR data (see above).  390m Double Sub-Pedwar total increases by one and confirmed as 26.





Pt. 394m, The Begwns    394m at SO 14433 44567

The 390m Double Sub-Pedwar status of this hill was announced on the Mapping Mountains site on 28.02.14, and its qualification to this sub list is due to the 394m summit spot height that appears on Ordnance Survey maps and an estimated bwlch height of c 374m based on bwlch contouring between 370m – 380m, these values give this hill c 20m of drop.  390m Double Sub-Pedwar total increases by one and confirmed as 25.





Craig Cefn Llech    398m at SN 95273 77148

This hill’s change in classification to a 390m Double Sub-Pedwar was announced on the Mapping Mountains site on 28.02.14, the hill qualifies for this category as it has 23m of drop based on a 398m summit and 375m bwlch spot height that appear on the Ordnance Survey enlarged mapping hosted on the Geograph website.  390m Double Sub-Pedwar total increases by one and confirmed as 24.





Mynydd Hendre Ddu    393m at SH 79627 12091

The classification of this hill to 390m Double Sub-Pedwar status was announced on Mapping Mountains on 28.02.14, and it qualifies for this category of hill as it has a 393m summit and 369m bwlch spot height that appear on the Ordnance Survey 1:25,000 Explorer map, giving this hill 24m of drop.  390m Double Sub-Pedwar total increases by one and confirmed as 23.





Ffridd Dyfnant    399m at SH 99700 16406

This hill was announced as a 390m Double Sub-Pedwar on the Mapping Mountains site on 28.02.14, its qualification to this category of hill is due to its 399m summit spot height and the 378m bwlch spot height which gives this hill 21m of drop, with the latter spot height appearing on the Ordnance Survey enlarged mapping hosted on the Geograph website.  390m Double Sub-Pedwar total increases by one and confirmed as 22.





Carreg y Frân    396m at SH 96101 14049

This hill’s classification as a 390m Double Sub-Pedwar was announced on Mapping Mountains on 28.02.14, the hill qualifies with a minimum 20m of drop based on the 396m summit and 376m bwlch spot height on the Ordnance Survey 1:25,000 Explorer map.  390m Double Sub-Pedwar total increases by one and confirmed as 21.





Pt. c 395m    c 395m at SJ 24914 40228

The Mapping Mountains site announced the qualification of this hill as a 390m Double Sub-Pedwar on 28.02.14, with the hill’s classification to this category due to it having an estimated summit height of c 395m based on the small 395m ring contour at its summit and an estimated bwlch height of c 374m based on bwlch contouring between 370m – 375m, with these values giving this hill c 21m of drop.  390m Double Sub-Pedwar total increases by one and confirmed as 20.





Ffridd Felen    392m at SH 85502 38841

The 390m Double Sub-Pedwar status of this hill was announced on the Mapping Mountains site on 28.02.14, the hill qualifies for this category with c 21m of drop based on the 392m summit spot height on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 371m.  390m Double Sub-Pedwar total increases by one and confirmed as 19.





Derwydd Bach    399m at SJ 01776 50304

This hill’s qualification as a 390m Double Sub-Pedwar was announced on the Mapping Mountains site on 28.02.14, and it qualifies for this category as it has a 399m summit spot height on Ordnance Survey 1:25,000 Explorer maps and an estimated bwlch height of c 372m, giving this hill c 27m of drop.  390m Double Sub-Pedwar total increases by one and confirmed as 18.





Boncyn Nadroedd    c 390m at SJ 02731 54040

The classification of this hill to 390m Double Sub-Pedwar status was announced on the Mapping Mountains site on 28.02.14, and prior to the identification of this hill qualifying for this category it had not been listed in any other hill list known to the authors.  With an estimated summit height of c 390m based on a tiny uppermost 390m ring contour and an estimated bwlch height of c 367m based on contouring between 360m – 370m, this hill has c 23m of drop and therefore qualifies as a 390m Double Sub-Pedwar390m Double Sub-Pedwar total increases by one and confirmed as 17.



6th January 2014 – Haroldstreet publishes Y Pedwarau. 

390m Double Sub-Pedwar total confirmed as 16.




23rd May 2013 – Europeaklist publishes Y Pedwarau. 

390m Double Sub-Pedwar total confirmed as 16.






Myrddyn Phillips and Aled Williams (January 2017)







Saturday, 28 January 2017

Mapping Mountains – Hill Reclassifications – Y Pedwarau


Pt. 391.9m (SN 998 433) - 390m Double Sub-Pedwar deletion

There has been a deletion of a 390m Double Sub-Pedwar by analysis of LIDAR data by Aled Williams.  The 390m Double Sub-Pedwarau is one of three categories of sub hills that accompany the main Y Pedwarau list, with the criteria for 390m Double Sub-Pedwar status being all Welsh hills at or above 390m and below 400m in height with 20m or more and below 30m of drop.

The hill is situated in the group of hills known as Mynydd Epynt with its Cardinal Hill being Clepyn Melyn (SN 961 464) and is placed in the Region of Mid and West Wales (B-2).  The hill is positioned between the small communities of Upper Chapel to the south south-east and Garth to the north-west, and can be easily accessed from the B 4519 road which is just to its west, however the hill is positioned within the Sennybridge Training Area and any prospective visitors should be aware of the access restrictions that apply.

As the authors do not know a local or an historical name for this hill it is being listed by the point (Pt. 391.9m) notation, the hill had been added to the Y Pedwarau sub list of 390m Double Sub-Pedwarau after the Europeaklist booklet was published in May 2013 and its inclusion in this sub category was reported on the Mapping Mountains site.  It was included in this sub category with a 393m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 373m based on bwlch contouring between 370m – 380m, with these values giving this hill the minimum qualifying drop of c 20m.

Since this hill’s inclusion in the 390m Double Sub-Pedwar category Aled has analysed this hill’s credentials against LIDAR data.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data gives the hill the following details:


Pt. 391.9m

Summit Height:  391.9m

Summit Grid Reference:  SN 99803 43305

Bwlch Height:  372.0m

Bwlch Grid Reference:  SN 99998 43782

Drop:  19.9m


Therefore, the 391.9m LIDAR data produced for the summit position at SN 99803 43305 and the 372.0m LIDAR data produced for the bwlch position at SN 99998 43782 which gives this hill 19.9m of drop is insufficient for this hill to retain its 390m Double Sub-Pedwar status as its drop is below the minimum of 20m.


The full details for the hill are:

Cardinal Hill:  Clepyn Melyn

Summit Height:  391.9m (LIDAR data)

Name:  Pt. 391.9m

OS 1:50,000 map:  147, 160

Summit Grid Reference:  SN 99803 43305

Drop:  19.9m (LIDAR data)


This now brings the overall total for the 390m Double Sub-Pedwarau to 26 hills with 13 additions and three deletions to this sub category of hill since publication of the list by Europeaklist in May 2013.  The hill will be taken out of the 390m Double Sub-Pedwar list in forthcoming publications of the Y Pedwarau.  The list of Pedwar hills is available from the Haroldstreet website (January 2014) with all subsequent changes available via the Mapping Mountains site.

The additions, reclassifications and deletions to the 390m Double Sub-Pedwarau since the 1st edition of the Y Pedwarau was published by Europeaklist are as follows:



390m DOUBLE SUB-PEDWAR ADDITIONS

















 
390m DOUBLE SUB-PEDWAR DELETIONS




Pt. 391.9m (LIDAR data) (SN 998 433) 391.9m summit and 19.9m drop




Myrddyn Phillips and Aled Williams (January 2017)