Sunday, 31 July 2016

Mapping Mountains – Significant Height Revisions – Y Trichant


Penmaen Mawr (SH 704 752)

There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 that was conducted on the 14th July 2016 to a hill that is listed in the Y Trichantwith the hill subsequently analysed with LIDAR data by Aled Williams and it is the latter result that is being detailed in this Significant Height Revisions post.

The criteria for the listing that this height revision affects are:

Y Trichant - Welsh hills at and above 300m and below 400m in height that have 30m minimum drop.  Sub-Trichant - Welsh hills at and above 300m and below 400m in height that have 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips and the Introduction to the list and its re-naming has been published on Mapping Mountains.

The hill is named Penmaen Mawr  and it is situated in the Carneddau range of hills, and is positioned above and to the immediate south of the busy A 55 as it heads westward between the towns of Penmaenmawr and Llanfairfechan, which are situated to the hill’s east and west respectively.


The summit is a part of the hill named Penmaen Mawr and the extended hill has been quarried with its old 1,550ft (472m) map heighted summit now a distant memory as the whole inner section of the summit has been blown apart leaving two remaining tops with this post concentrating on the lower easterly summit.

The lower easterly summit is impressive as it forms a sheer rock face from its south and has steep slopes descending northward to the A 55 below.  Each summit is listed by the same name of Penmaen Mawr as they are both a part of the hill that is known by this name.

The summit area for the whole of Penmaen Mawr now appears on Ordnance Survey maps as a blank area with ‘Quarries’ written over it, and therefore is devoid of any uppermost continuous contour rings, which is the norm for the representation of quarried areas on Ordnance Survey maps, with the highest contour line being 350m for the area where the lower easterly peak is situated.

Therefore this hill’s new summit height is 385.8m (LIDAR data) which is 35.8m higher than its uppermost contour line on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and its 31.3m drop value is sufficient for it to be classified as a Trichant.


The full details for the hill are:

Cardinal Hill:  Tal y Fan

Summit Height:  385.8m (LIDAR data)

Name:  Penmaen Mawr

OS 1:50,000 map:  115

Summit Grid Reference:  SH 70441 75241

Drop:  31.3m (LIDAR data)



Aled with Penmaen Mawr (SH 704 752) in the background

Myrddyn Phillips (July 2016)



Saturday, 30 July 2016

Mapping Mountains – Significant Name Changes – Y Pedwarau


Gwastad Mawr (SJ 210 349)

There has been a Significant Name Change to a hill that appears in the Y Pedwarau, and the following details are in respect of a hill whose summit and bwlch was surveyed with the Trimble GeoXH 6000 on the 29th April 2015 and 7th June 2015 respectively.

The criteria for the list that this name change affects are:

Y Pedwarau These are the Welsh hills at and above 400m and below 500m in height that have 30m minimum drop,  with the introduction to the Mapping Mountains publication of this list appearing on the 30th January 2017, with the list being co-authored by Myrddyn Phillips and Aled Williams.

The hill is part of the Y Berwyn, which is an extensive group of hills situated in the south-eastern part of north Wales.  The hill is positioned with the town of Glyn Ceiriog to its north, and with the small communities of Craignant and Selattyn towards its east.

The Trimble GeoXH 6000 gathering data at the summit of Gwastad Mawr

The hill appeared in the 400m P30 list on Geoff Crowder’s v-g.me website under the name Pen y Gwely North Top, with an accompanying note stating; Name from hill to the South.  



Pen y Gwely North Top
   449m
   SJ211349
   126
  240/255
  Name from hill to the South


During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them, or as in this instance, use the name of another hill as a directional name as no other map name seemed suitable for the listed hill.  This is not a practice that I now advocate as with research either conducted locally or historically an appropriate name for the hill can usually be found.

The name this hill is now listed by in the Y Pedwarau is Gwastad Mawr, and this was derived from the Ordnance Survey One-Inch ‘Old Series’ map.

An extract from the Ordnance Survey One-Inch 'Old Series' map

The One-Inch ‘Old Series’ was the first map that Ordnance Survey published, and  they were based on the preceding Draft Surveyors map.  Their publication culminated from the whole of Britain being surveyed between 1791 and 1874 and the detail gathered therein produced at a scale of one inch to the mile and published in sheet format between 1805 and 1874.  The One-Inch ‘Old Series’ maps for the whole of Wales are now available online; they are also available in map format as enlarged and re-projected versions to match the scale and dimensions of the Ordnance Survey 1:50,000 Landranger series and are published by Cassini.  This series of maps forms another important part in the study of Welsh upland place-names and bridge the time frame leading to the production of the Ordnance Survey base map of the Six-Inch series.


The full details for the hill are:

Group:  Y Berwyn

Name:  Gwastad Mawr

Previously Listed Name:  Pen y Gwely North Top 

Summit Height:  448.9m (converted to OSGM15)

OS 1:50,000 map:  126

Summit Grid Reference:  SJ 21055 34971 
 
Drop:  35.2m (converted to OSGM15)



For details on the summit and bwlch survey of Gwastad Mawr

Myrddyn Phillips and Aled Williams (July 2016)





Friday, 29 July 2016

Mapping Mountains – Hill Reclassifications – Y Pedwarau


Penmaen Mawr (SH 698 755) - 390m Double Sub-Pedwar addition

There has been an addition to the 390m Double Sub-Pedwar category due to a survey with the Trimble GeoXH 6000.  The hill was not classified prior to the survey with the Trimble, but at one stage in its illustrious career the hill met both Hump and Pedwar criteria as it was given a 1,550ft (472m) map height on the Ordnance Survey Popular and New Popular One-Inch maps, with this height also appearing on the Ordnance Survey Six-Inch map published in 1888.

The hill no longer meets the qualification for these listings as its summit has been quarried and current Ordnance Survey maps only give it an uppermost 370m contour line.  However, quarried areas are usually given no contour lines on Ordnance Survey maps indicating that the ground is or has been in flux, and photographic and map study by Aled indicated that the remaining high point was substantially higher than 370m.

The 390m Double Sub-Pedwarau are the hills at or above 390m and below 400m in height with a drop between 20m and below 30m, with the 390m Sub-Pedwarau being the hills within the same height band and with a minimum 30m of drop.

The hill is situated in the northern part of the Carneddau, and has the towns of Llanfairfechan to its west and Penmaenmawr to its east, with the latter taking its name from the hill.

The name of the hill is Penmaen Mawr and it can be easily accessed from a minor road to the south of the summit that reaches over 260m in height, a public footpath heads north from just below the high point of this minor road and joins a bridlewayed track that contours around the southern slopes of the upper section of the hill.  A large section of the land above the bridleway is open access and the summit of Penmaen Mawr is close to this.

Therefore, Penmaen Mawr is the first hill to be reclassified to the listing of 390m Double Sub-Pedwar hills due to a survey with the Trimble GeoXH 6000 and the list of the Y Pedwarau will be updated accordingly.  The list of Pedwar hills is available from the Haroldstreet (January 2014) website and amendments to the list since this publication have been subsequently reported on the Mapping Mountains site.


The full details for the hill are:

Cardinal Hill:  Carnedd Llywelyn

Summit Height:  390.4m (converted to OSGM15)

Name:  Penmaen Mawr

OS 1:50,000 map:  115

Summit Grid Reference:  SH 69865 75523 
  
Drop:  26.9m (converted to OSGM15)



Penmaen Mawr (SH 698 755) now confirmed as a 390m Double Sub-Pedwar



Myrddyn Phillips and Aled Williams (July 2016)












Thursday, 28 July 2016

Mapping Mountains – Significant Name Changes – Y Trichant


Coed y Cefn (SN 950 682)

There has been a Significant Name Change to a hill that is listed in the Y Trichant, and the following details are in respect of a hill that was surveyed with the Trimble GeoXH 6000 on the 14th April 2015.

The criteria for the list that this name change affects are:

Y Trichant These are the Welsh hills at and above 300m and below 400m in height that have 30m minimum drop,  with the introduction to the re-naming and the publication history of this list appearing on Mapping Mountains on the 13th May 2017.

The hill is situated in the Elenydd, which is a range of hills taking in vast tracts of wild moor and is situated in the central heartland of Wales.  The hill is positioned 2 km west of the town of Rhaeadr Gwy (Rhayader) which is beside the Afon Gwy (River Wye).

Coed y Cefn (SN 950 682)

The hill appeared in the 300m P30 list on Geoff Crowder’s v-g.me website under a partly invented name of Ochr-cefn, with an accompanying note stating; Name from buildings to the West.  During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them, or as in this instance, just use the name of the farm which appears close to this hill’s summit on the Ordnance Survey 1:50,000 Landranger map.  This is not a practice that I now advocate as with research either conducted locally or historically an appropriate name for the hill can usually be found.

An extract from the Ordnance Survey 1:50,000 Landranger map with the name Ochr-cefn appearing near to the summit of this hill


Ochr-cefn
    340c
    SN951682
    136/147
  200
    Name from buildings to the West


Since publication of these P30 lists there have been a number of Ordnance Survey maps made available online, some of these are historical such as the series of Six-Inch maps on the National Library of Scotland website, whilst others are current and digitally updated such as the enlarged map on the Geograph website.  This latter map also includes many spot heights that do not appear on any other publicly available map, and it was the study of this map that necessitated the change in this hill’s listed name.

An extract from the Ordnance Survey enlarged map hosted on the Geograph website

The Ordnance Survey enlarged map hosted on the Geograph website gives this hill a 342m spot height at its summit, and with a 252m spot height on the area of its bwlch it means this hill has 90m of map prominence, which is the minimum value required to be classified as a Subhump.  These details were posted on the RHB Yahoo group forum on 06.12.13, see below:


Sub-HuMP enthusiasts may find the following of interest:

Coed y Cefn    SN 950 682    342m summit    252m bwlch at SN 943 684

Ochr-cefn being the name of a farm and not that of the hill.  With Coed y Cefn supported by various old maps.

Myrddyn


Excluding all near farm names it is the name Coed y Cefn that appears nearest to this hill’s summit on the enlarged Geograph map and this is supported by a number of other maps, including the Ordnance Survey Six-Inch, the historical and the current 1:25,000.  Except for the current Ordnance Survey 1:25,000 Explorer map which is prone to inappropriate placement of hill and feature names, all other maps are consistent in the placement of the name Coed y Cefn. 

An extract from the current Ordnance Survey 1:25,000 Explorer map.

Therefore, the name this hill is now listed by in the Y Trichant is Coed y Cefn and this was derived from a number of different scaled Ordnance Survey maps. 


The full details for the hill are:

Group:  Elenydd

Name:  Coed y Cefn

Previously Listed Name:  Ochr-cefn 

Summit Height:  342.2m (converted to OSGM15)

OS 1:50,000 map:  136, 147

Summit Grid Reference:  SN 95076 68217
  
Drop:  90.8m (converted to OSGM15)




Myrddyn Phillips (July 2016)



Wednesday, 27 July 2016

Mapping Mountains – Significant Height Revisions – Y Pedwarau and Y Trichant


Penmaen Mawr (SH 698 755)

There has been a Significant Height Revision initiated by a survey with the Trimble GeoXH 6000 to a hill that is listed in the Y Pedwarau and the Y Trichant, with the survey that resulted in this height revision being conducted on the 14th July 2016.

The criteria for the listings that this height revision affects are:

Y Pedwarau - Welsh hills at and above 400m and below 500m in height that have 30m minimum drop.  300m Double Sub- Pedwarau - Welsh hills at and 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.

Y Trichant - Welsh hills at and above 300m and below 400m in height that have 30m minimum drop.  Sub-TrichantWelsh hills at and above 300m and below 400m in height that have 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips and the Introduction to the list and its re-naming has been published on Mapping Mountains.

The hill is named Penmaen Mawr  and it is situated in the Carneddau range of hills, and is positioned above and to the immediate south of the busy A 55 as it heads westward between the towns of Penmaenmawr and Llanfairfechan, which are situated to the hill’s east and west respectively.

The summit area of Penmaen Mawr has been quarried, and prior to the first quarry opening in 1830 and the subsequent resulting expansion of operations the hill was substantially higher, with a 1,550ft (472m) map height given it on the Ordnance Survey Popular and New Popular One-Inch maps, with this height also appearing on the Ordnance Survey Six-Inch map published in 1888.

The quarrying of this hill has created two summits with a gaping hole between, the westerly summit is higher than the easterly, although the latter is more impressive due to a shear rock face leading toward its high point.  Each summit is listed by the same name of Penmaen Mawr as they are both a part of the hill that is known by this name, and their height data is given below:

Penmaen Mawr:  390.4m (converted to OSGM15, Trimble GeoXH 6000) at SH 69865 75523

Penmaen Mawr:  385.8m (LIDAR data) at SH 70292 75649

Over recent years the summit area of this hill has appeared without any uppermost contour lines as is the norm for quarried ground that is represented on Ordnance Survey maps, with the highest contour being 370m which appears on the upper western part of this hill.

Therefore this hill’s new summit height is 390.4m (converted to OSGM15) which is 20.4m higher than its uppermost contour on Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps.


The full details for the hill are:

Cardinal Hill:  Tal y Fan

Summit Height:  390.4m (converted to OSGM15)

Name:  Penmaen Mawr

OS 1:50,000 map:  115

Summit Grid Reference:  SH 69865 75523

Drop:  26.9m (converted to OSGM15)


The Trimble GeoXH 6000 gathering data 0.39m above the summit of Penmaen Mawr (SH 698 755) which resulted in this hill's significant height revision



Myrddyn Phillips and Aled Williams (July 2016)






Tuesday, 26 July 2016

Mapping Mountains – Significant Name Changes – 100m Twmpau


Courthouse Bank (SJ 247 183)

There has been a Significant Name Change to a hill that is listed in the 100m Twmpauand the following details are in respect of a hill that was surveyed with the Trimble GeoXH 6000 on the 20th March 2015.

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

100m Twmpau - All Welsh hills at and above 100m and below 200m in height that have 30m minimum drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

The hill is a part of the Carnedd Wen range, which is an extensive group of hills situated in the southern part of north Wales, and it is positioned between the small communities of Llanymynech to the north-east, Llansantffraid-ym-Mechain to the north-west, Ardd-lin (Arddleen) towards the south and Four Crosses to the east.

The summit of Courthouse Bank

The hill appeared in the 100m P30 list on Geoff Crowder’s v-g.me website under an invented name of Court House Top, with an accompanying note stating; Name from house to the South-West, with Court House being the name of a house.  During my early hill listing I thought it appropriate to invent a name for a hill if no name seemed to appear for it on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them, occasionally I used other names and for those that were English ones, I usually added the suffix of Top.  This is not a practice that I now advocate as with research either conducted locally or historically an appropriate name for the hill can usually be found.


Court House Top
    150c
    SJ248183
    126
 240
    Name from house to the South-West


The name this hill is now listed by is Courthouse Bank, and this was derived from the Ordnance Survey enlarged mapping hosted on the Geograph website.  This mapping became publicly available after the original P30 lists were published on Geoff Crowder’s v-g.me website.

Detail from the Ordnance Survey enlarged mapping hosted on the Geograph website

Since the publication of these P30 lists there have been a number of historical Ordnance Survey maps made available online, some of these include the Six-Inch maps on the National Library of Scotland website, much of the place-name information on these maps were the source for what now appears on the Ordnance Survey enlarged mapping hosted on the Geograph website.

Detail from the Ordnance Survey Six-Inch map, with the name Courthouse Bank first appearing on the 1887 map on the National Library of Scotland website


The full details for the hill are:

Group:  Carnedd Wen

Name:  Courthouse Bank

Previously Listed Name:  Court House Top
 
Summit Height:  149.5m (converted to OSGM15)

OS 1:50,000 map:  126

Summit Grid Reference:  SJ 24787 18328 

Drop:  33.6m (converted to OSGM15)




Myrddyn Phillips (July 2016)






Monday, 25 July 2016

Mapping Mountains – Trimble Surveys – Carneddau


14.07.16  Penmaen Mawr (SH 698 755), Penmaen Mawr (SH 702 756), Clip yr Orsedd (SH 711 747) and Moelfre (SH 717 744)

Penmaen Mawr (SH 698 755)

When seen from the A 55 the northern aspect of Penmaen Mawr rises in scree laden slopes to what was once a proud and prominent hill.  This hill has now been quarried and where a 1,550ft (472m) map heighted summit once was, there is now a gaping hole.  Quarrying this hill also destroyed an ancient hill fort that encircled the summit.  In its time Penmaen Mawr would have been an impressive hill as along with its ancient hill fort it was prominent above its surrounding lands as the bwlch that connected this hill to its adjacent neighbour of Clip yr Orsedd is, according to current maps, between 360m – 370m in height, giving the old hill over 100m of prominence.

Destroying the hill has meant that Penmaen Mawr can no longer be considered for Hump (HUndred Metre Prominence) status, and that its Pedwar (Welsh 400m hills) status has long gone with the last stick of dynamite used to blow the summit area to bits.  However, no accurate summit height is known for what remains of the hill and it had long been a priority to survey.

I met Aled at 5.00pm in Dwygyfylchi where we left his van and continued in my car to our parking spot high on a minor road above Llanfairfechan.  It was only a short walk up a track to the bwlch connecting Penmaen Mawr with Clip yr Orsedd, and when we arrived it was relatively easy to pinpoint its critical position.

As the Trimble gathered five minutes of data we chatted with a man who was out for an evening walk, and once the data set was complete I packed the equipment away and started up the gravelled slopes of quarried debris toward the first high point of what remains of the hill.

Gathering data at the critical bwlch of the two Penmaen Mawr summits

This first high point was no more than a mound of quarry debris and we had both spotted it when driving on the A 55 earlier in the day as it rises steeply and is pronounced.  Remarkably it was relatively stable when we climbed up it.  As the Trimble gathered data I stood immediately below it whilst Aled wandered over to look down into the gaping hole of the quarry.  Dotted about where remains of ancient and relatively modern habitation with the lower rock walls of ancient round huts still to be found, whilst the old quarry had its own more modern buildings, many now dilapidated and left to nature’s way.

Aled with the lower of the two Penmaen Mawr summits in the background

Over recent days Aled had scrutinised this hill via photographs and maps and realised that the easterly point of what remains of the hill may have sufficient prominence to be classified as a Sub or even a P30, and therefore after making our way over to the remaining natural high point and Trimbling it we headed down to the connecting land between the westerly and easterly high points, this proved to be on a steep mound of gravel beside long grasses and nettles, it too was also Trimbled.

Gathering data from the higher of the two Pernmaen Mawr summits

Heading toward the bwlch connecting the summit of Penmaen Mawr with the lower easterly summit

What remains of the hill on what is now its easterly high point is impressive as the quarry has gauged the upper hill into a cliff which gave us a little hands on rock excitement, once on its ridge the view down the coast toward Gogarth and Llandudno sprang into view.  The ridge was fun and gave us a small scramble of sorts with the drop to our right increasing as height was gained.

The southern face of the lower of the two Penmaen Mawr summits consists of an impressive looking rock face

Since the survey with the Trimble GeoXH 6000 Aled has analysed LIDAR data and the high point of the hill is not where data was gathered from and therefore the details given later in this post are those taken from LIDAR data.  When we reached what we thought to be the high point I set the Trimble on a large rock which was immediately above a gaping drop, not wanting to lose the Trimble to an early death I set it up on its dog lead, aligned its internal antenna with the highest part of the rock and sat below it with the lead fixed to the Trimble and securely around my wrist for the five minutes of data collected.

Heading toward the lower of the two Penmaern Mawr hills

Gathering data on the lower of the two Penmaen Mawr hills

The view east toward the shapely Foel Lus

As we headed down to the track where the first data set for the bwlch for Penmaen Mawr had been gathered, there was also an alternate connecting bwlch for the easterly high point to survey, this we thought to be on a track and connected the easterly high point to the higher Penmaen Mawr.

Gathering data at the area of the bwlch of the lower of the two Penmaen Mawr summits

However, the surveying of Penmaen Mawr had not ended as there was also an alternate bwlch position to survey for the high point of the hill, and this was on the way up towards our next hill; Clip yr Orsedd.  Once five minutes of data were gathered from this point we walked up to the summit of Clip yr Orsedd as the sun disappeared into a milky sky.

Our original plan was to do a two car walk and continue as far as Foel Lus, a 362m map heighted hill at SH 732 761, but we’d already conducted eight surveys and been on the hill for three hours, and if we continued toward Foel Lus in all likelihood we’d be descending a steep hill in darkness, therefore we quickly revised our plan and decided to continue to Moelfre and descend the green track on the southern side of Clip yr Orsedd straight back to my awaiting car.

Gathering data at the summit of Clip yr Orsedd

By now an evening’s chill had set in and the slow ebb of dusk was gathering.  Beyond the summit of Clip yr Orsedd we joined a path heading down toward its connecting bwlch with Moelfre, we assessed the lay of land and decided that the critical point was beside the track which crosses a reed invested bog, once five minutes of data were gathered we wandered up the steep northern slopes of Moelfre.

This hill has two potential positions for its critical bwlch and time dictated that only one could be surveyed, so after a five minute data set was collected at the summit I set the Trimble up at the neatest bwlch position and Aled wandered off in the direction of Tal y Fan to inspect the other bwlch option.  The bwlch nearest to Tal y Fan looked decidedly lower, and although a visual inspection is not ideal as the human eye can have difficulty judging hill heights, it did at least give us inkling which was lower and therefore the position of the critical bwlch of Moelfre.

Gathering data at the summit of Moelfre

As the Trimble gathered the last of its 300 data points, Aled re-appeared and said that the bwlch nearest to Tal y Fan looked at least 3m lower than where the Trimble was now gathering data, this was important as this hill is currently listed as a Sub-Pedwar with a drop of c 21m, so the position and height of its critical bwlch is all important.

After packing the Trimble away we walked down to the green track and followed it in dimming light arriving back at my car at 9.50pm.


Survey Result:


Penmaen Mawr

Summit Height:  390.4m (converted to OSGM15) (significant height revision and 390m Double Sub-Pedwar addition confirmed)

Summit Grid Reference:  SH 69865 75523

Bwlch Height:  363.5m (converted to OSGM15)

Bwlch Grid Reference:  SH 70332 75118


Dominance:  6.90% 

 

Penmaen Mawr

Summit Height:  385.8m (LIDAR data) (significant height revision)

Summit Grid Reference:  SH 70292 75649

Bwlch Height:  354.5m (LIDAR data)

Bwlch Grid Reference:  SH 70441 75241


Dominance:  8.11%


  
Clip yr Orsedd

Summit Height:  426.6m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SH 71185 74743

Bwlch Height:  387.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 71805 74678

Drop:  39.5m

Dominance:  9.25%



Moelfre

Summit Height:  433.0m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SH 71733 74418

Bwlch Height:  414.7m (LIDAR data)

Bwlch Grid Reference:  SH 72253 74153 (LIDAR data)

Drop:  18.3 (400m Sub-Pedwar deletion confirmed)

Dominance:  4.23%