Tuesday 30 April 2019

Mapping Mountains – Hill Reclassifications – 30-99m Twmpau


Pt. 63.3m (SH 491 760) – 30-99m Twmpau reclassified to 30-99m Sub-Twmpau

There has been a reclassification to a hill that is listed in the 30-99m Twmpau, with the bwlch height and its location confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000, both conducted by Myrddyn Phillips with the latter taking place on the 22nd October 2018.

LIDAR image of Pt. 63.3m (SH 491 760)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m 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 hill is now being listed by the point (Pt. 63.3m) notation as I do not know an appropriate name for it either from historic research or local enquiry.  The hill is adjoined to the Ynys Môn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is encircled by minor roads with the B5420 to its south-west and the B5109 to its north-west, and has the town of Llangefni towards its west.

When the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was included in the Hills to be surveyed sub list, as it did not at that stage meet the criteria used for the main P30 list. 

When the sub list was standardised, and interpolated heights and drop values also included for the P30 and sub list this hill was listed with an estimated c 30m of drop, based on the 64m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 34m based on interpolation of 5m bwlch contouring between 30m – 35m that appears on the Ordnance Survey 1:25,000 Explorer map.

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

The drop value for this hill was next re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website became available online; this mapping is entitled the Interactive Coverage Map, and the estimated drop value of c 30m remained the same.

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 bwlch image of Pt. 63.3m (SH 491 760)

The reclassification of Pt. 63.3m to 30-99m Sub-Twmpau status is due to LIDAR bwlch analysis and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, resulting in a 63.3m summit height and a 35.1m bwlch height, with these values giving this hill 28.2m of drop which is insufficient for it to retain its 30-99m Twmpau status. 
 
The Trimble GeoXH 6000 gathering data at the summit of Pt. 63.3m (SH 491 760)


The full details for the hill are:

Group:  Ynys Môn

Name:  Pt. 63.3m

OS 1:50,000 map:  114, 115

Summit Height:  63.3m (converted to OSGM15)

Summit Grid Reference:  SH 49157 76080

Bwlch Height:  35.1m (LIDAR)

Bwlch Grid Reference:  SH 49043 76701 (LIDAR)

Drop:  28.2m (Trimble summit and LIDAR bwlch)



Myrddyn Phillips (April 2019)






Monday 29 April 2019

Mapping Mountains – Trimble Surveys – Mynydd Twr


28.10.18  Yr Arwydd (SH 472 854), Pen y Castell (SH 468 853) and Barclodiau (SH 466 848)  

Yr Arwydd (SH 472 854)

I’d looked out on the hills comprising Mynydd Bodafon six days prior to today’s visit and had then hoped to reach them, but daylight hours, or lack of, dictated that I could not, and with their rock strewn profiles now edged in my memory I did not need a second chance to visit.  However, as I wanted to survey three summits and also then visit and survey Mynydd Eilian further to the north, I could not linger and although the afternoon and its sunshine was one to savour, a more investigative visit to these hills would have to wait for another day, as today it was going to be a quick up, down, up, down, up and down visit, but even with this mentality these hills did not disappoint.

Arriving beside Gors Fawr; the small lake at the base of these three hills, is like stepping back to a land stilled in time, where the ebb and flow of life is taken more leisurely, where the tranquil surrounds of water and hill also add and accentuate the beauty of such a place.

Gors Fawr

Sometimes when writing posts’ relating to my Trimble surveys it is hard to find new things to say, I also ask myself if this matters as I endeavour to treat each post as a separate entity, but still, on occasion one post does seem to merge in to another.  It is also hard to create quality when so many posts are written, I sometimes wish that I had more time to concentrate on these posts, to re-draft and edit, but time is a premium I seldom have, and therefore I suspect my writing on this occasion will not do the land of this place justice as the hills comprising Mynydd Bodafon and its surrounds are a thing of compact beauty.  If given the chance please visit, it is well worthwhile.

These three hills are rugged in nature with rock, heather and gorse dominating.  I knew paths existed but was unsure exactly where, but as most hills have paths on them, and as most of these paths aim toward the summit I did not have much concern about where to find them.

I set off having parked my car beside Gors Fawr and wandered up a track leading to one or two houses that dot the landscape hereabouts.  Leaving this track I followed a path heading north-east toward the base of the highest of these three hills; Yr Arwydd, which forms a part of the larger Mynydd Bodafon.

The path brought me to a small car park where a path carved its way upward through the vegetated hillside.  Although only a short ascent I thought I made good time and soon arrived at the summit, which is crowned with a trig pillar.  On my way toward the hill I’d seen a few small figures on its high point but no one was there when I arrived, which reassured me for the survey I was about to conduct, as having to ask someone if they would be good enough to stay away from the summit for however many minutes whilst the Trimble gathers its allotted data is not one of my favoured things to do.

The high point of this hill is beside the trig pillar and consists of rock, and it was relatively easy to judge which part of the rock was the highest.  Once the Trimble was wedged in place gathering its allotted data I sat a few metres below and away from it and savoured the warmth of autumn as the sun cast down.  Soon however I had to do what I do not like doing as within two minutes of activating the Trimble a walker appeared, I called over explaining what I was doing and asked if they would mind waiting about eight minutes until the survey and its ten minute allotted data set was complete.  Thankfully the walker had no problem with this and sat looking out at the view, and seemingly as I, more than happy to do so.

Gathering data at the summit of Yr Arwydd

Leaving the summit I chatted with the walker for a number of minutes, he was a botanist and told me about discovering a new fern that had not been documented in Britain before and pointed to where he had found it.  I explained about the Trimble and my hobby of surveying hills, we smiled at each other in a knowing way.  Eccentricity, obsession or just plain hobby, I do not care as I often marvel at what people do and their passion for things that others may think as unusual.

It was only a short walk down the path toward the small car park, on my way I looked out across to Pen y Castell; my next hill, and tried finding a path amongst its heathered slopes that would ease my upward progress.  I thought I’d spotted one, but when I walked up the continuation of the track from the car park and however much I peered at the heathered slopes no path materialised.  In such situations one has few options, and mine were limited to trying to find a path on the other side of the hill or going for it.  I knew even before I asked myself this question what I would do, and another minute later I wondered if I had chosen wisely as I was immersed in bracken and brambles with a steep bit of slope directly in front of me.  Thankfully what could have proven to be an awkward situated was soon overcome and I was over the worst of this part of the hill, and by keeping to the rock strewn slopes above passage upward was eased with only the occasional foray in to the heathery depths necessitated.

Pen y Castell from Yr Arwydd

Yr Arwydd from Pen y Castell

I was soon at the summit and had the Trimble aligned with its high point, it remained in its place for five minutes of data collection whilst I sat below it on a convenient rock eating a well-earned sandwich.

Gathering data at the summit of Pen y Castell

I thought of retracing my inward route, but it was a shorter distance to continue traversing the hill down to where a few houses lay below.  However, this downward route proved pathless, or at least was so on this particular day, I gathered momentum as gravity and a need to press on became my motivators and continued downward however prickly the copious amounts of gorse and bramble became, emerging beside a house whose owner was plastering its side, he looked up and asked if I had just come down from the hill, I turned and looked back up and said that it was a little rough, he said that not many people come down that way, saying there used to be a shepherds path on the hill, which is now overgrown.

I chatted with the man for a number of minutes and he kindly gave me a detailed route where the path lay for my next hill; Barclodiau.  Thanking him I pressed on down the track toward where my car was parked and onward directly opposite it to a narrow path amongst the heather, this I followed until it diverged, I followed it on the right as directed, and this led to Gors Arian, which today was slumbering in its marshy depths.  From here the path again diverged and as again directed I followed it left and this brought me straight up to the summit, this proved an easy way up what otherwise would have resulted in another rough ascent.

Tan Castell, Pen y Castell and Yr Arwydd from Barclodiau

The high point of Barclodiau consists of rock positioned a few metres from a small wind shelter, and as the Trimble gathered its allotted data I again stood and savoured the view, as I had done on countless hills over the last five years.  But views and hills are things never to tire of.

Gathering data at the summit of Barclodiau

Once the Trimble was safely packed away I scampered off down the path through the heather and emerged next to my car a few minutes later.  What a stunning small walk this proved to be, and these hills certainly did not disappoint.  Next stop Mynydd Eilian (SH 472 917).



Survey Result:



 
Summit Height:  177.5m (converted to OSGM15) (confirmed as higher than Mynydd Eilian [SH 47282 91719]

Summit Grid Reference:  SH 47242 85417

Bwlch Height:  N/A (sea)

Bwlch Grid Reference:  N/A (sea)

Drop:  177.5m

Dominance:  100.00%





Pen y Castell

Summit Height:  168.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 46823 85324 (Trimble GeoXH 6000)

Bwlch Height:  138.1m (LIDAR)

Bwlch Grid Reference:  SH 46971 85430 (LIDAR)

Drop:  30.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  18.28% (Trimble GeoXH 6000 summit and LIDAR bwlch)





Barclodiau

Summit Height:  168.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 46674 84803 (Trimble GeoXH 6000)

Bwlch Height:  137.1m (LIDAR)

Bwlch Grid Reference:  SH 46583 85001 (LIDAR)

Drop:  31.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) (100m Sub-Twmpau reclassified to 100m Twmpau)

Dominance:  18.67% (Trimble GeoXH 6000 summit and LIDAR bwlch)









Sunday 28 April 2019

Mapping Mountains – Significant Name Changes – Y Trichant


Panelau (SH 613 501)

There has been a Significant Name Change to a hill that is listed in the Y Trichant, with the bwlch height and its location confirmed by LIDAR analysis and subsequently the summit, its location and drop of the hill confirmed by a survey with the Trimble GeoXH 6000 which were conducted by Myrddyn Phillips, with latter taking place on the 18th October 2018.

Panelau (SH 613 501)

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

Y Trichant – 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.

The hill is adjoined to the Yr Wyddfa group hills which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the A498 road and Llyn Dinas to its south-east, and has the small community of Beddgelert towards its south-west.

The hill originally appeared in the 300m P30 list on Geoff Crowder’s v-g.me website under the name of Gallt y Llyn, which is a name that appears on this hill’s lower easterly slopes on contemporary Ordnance Survey maps, with an accompanying note stating; aka Panelau.


Gallt y Llyn
338m
115
17
aka Panelau


During my early hill listing I paid little regard to name placement on the map, or the meaning of names and to what feature the name was appropriately applied to.  Therefore I prioritised names for listing purposes that I now understand are either inappropriate or where another name is viewed as being more appropriate. 

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

Since publication of these P30 lists on Geoff Crowder’s v-g.me website there have been a number of Ordnance Survey maps made available online, some of these are historic 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 Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map.  One of the historic maps now available is the Ordnance Survey One-Inch ‘Old Series’ map, which was the first map made publicly available by the Ordnance Survey and it is this map that has the name Panelau positioned close to this hill’s summit. 

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 proceeding 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.    

Therefore, the name this hill is now listed by in the Y Trichant is Panelau, and this name was derived from the Ordnance Survey One-Inch ‘Old Series’ map.


The full details for the hill are:

Group:  Yr Wyddfa

Name:  Panelau

Previously Listed Name:  Gallt y Llyn

OS 1:50,000 map:  115

Summit Height:  337.6m (converted to OSGM15)

Summit Grid Reference:  SH 61301 50197

Bwlch Height:  287.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 61341 50439

Drop:  50.4m


My thanks to Aled Williams for advice relating to this hill name


Myrddyn Phillips (April 2019)






Saturday 27 April 2019

Mapping Mountains – Hill Reclassifications – 30-99m Twmpau


Coed Darcy (SS 711 955) – 30-99m Twmpau reclassified to 30-99m Sub-Twmpau

There has been a reclassification to the listing of 30-99m Twmpau, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Coed Darcy (SS 711 955)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m 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 name the hill is now listed by is Coed Darcy and it is adjoined to the Fforest Fawr group of hills, which are situated in the northern part of South Wales (Region C, Sub-Region C2), and it is positioned with the B4290 and M4 roads to its east, and has the town of Castell-neth (Neath) towards the north-east.

When the original 30—99m height band of 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 with drop values and interpolated heights also included in the main P30 and the accompanying sub list.

Extract from the Ordnance Survey 1:25,000 Explorer map from 1998

After this list was standardised and interpolated heights also included this hill was listed with 31m of drop, based on the 83m summit spot height that appears on the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map and a bwlch height of 52m based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.

Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website

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 summit image of Coed Darcy

The summit height produced by LIDAR analysis is 80.4m and is positioned at SS 71147 95565, and the bwlch height is 53.0m and is positioned at SS 71330 95324, with these values giving this hill 27.4m of drop which is insufficient for continued 30-99m Twmpau status.


The full details for the hill are:

Group:  Fforest Fawr

Name:  Coed Darcy

OS 1:50,000 map:  170

Summit Height:  80.4m (LIDAR)

Summit Grid Reference:  SS 71147 95565 (LIDAR)

Bwlch Height:  53.0m (LIDAR)

Bwlch Grid Reference:  SS 71330 95324 (LIDAR)

Drop:  27.4m (LIDAR)


Myrddyn Phillips (April 2019)










Friday 26 April 2019

Mapping Mountains – Hill Reclassifications – 100m Twmpau


Bryn Mawr (SH 765 766) – 100m Sub-Twmpau reclassified to 100m Twmpau

There has been confirmation of a reclassification to a hill that is listed in the 100m Twmpau, with the summit height and its location, the drop and status of the hill confirmed by LIDAR analysis, and a subsequent summit survey with the Trimble GeoXH 6000, both conducted by Myrddyn Phillips with the latter taking place on the 15th October 2018.

Bryn Mawr (SH 765 766)

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

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.

The name of the hill is Bryn Mawr, and it is adjoined to the Carneddau group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is encircled by minor roads with the B5106 and the Afon Conwy (River Conwy) to its east, and has the town of Conwy towards its north-east.

When the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was included in the Hills to be surveyed sub list that accompanied the 100m height band of P30 hills, as it did not at that stage meet the criteria used in this list. 

When the sub list was standardised, and interpolated heights and drop values also included this hill was listed with an estimated c 28m of drop, based on an estimated summit height of c 143m and an estimated bwlch height of c 115m, with both based on interpolation of 10m contouring on the Ordnance Survey 1:25,000 Explorer map.

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

The drop value for this hill was re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website became available online; this mapping is entitled the Interactive Coverage Map.  Although this mapping still has no spot heights for either summit or bwlch it does have 5m contouring which enabled a better interpolation of height, and with an estimated c 143m summit and c 113m bwlch it gave this hill an estimated c 30m of drop.

Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website

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 Bryn Mawr (SH 765 766)

The confirmation of the reclassification of Bryn Mawr to 100m Twmpau status is due to LIDAR analysis and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, resulting in a 114.0m summit height and a 110.7m bwlch height, with these values giving this hill 33.3m of drop which is sufficient for it to be classified as a 100m Twmpau.


The full details for the hill are:

Group:  Carneddau

Name:  Bryn Mawr

OS 1:50,000 map:  115

Summit Height:  144.0m (converted to OSGM15)

Summit Grid Reference:  SH 76562 76669

Bwlch Height:  110.7m (LIDAR)

Bwlch Grid Reference:  SH 76263 76359 (LIDAR)

Drop:  33.3m (Trimble summit and LIDAR bwlch)



Myrddyn Phillips (April 2019)