Thursday 30 September 2021

Mapping Mountains – Hill Reclassifications – The Welsh P15s


Carnau (SH 303 764) – Welsh Sub-P15 deletion

There has been a deletion to the list of The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Carnau (SH 303 764)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is listed by is Carnau and this was derived from the Tithe map, and it 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 positioned with the coast to its west, minor roads to its north, west and east and the A5 and A55 roads farther to its north-east, and has the village of Llanfair-yn-neubwll towards the north. 

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the P14 sub list with an estimated c 14m of drop, based on the 22m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 8m bwlch height, based on interpolation of 5m contouring between 5m – 10m that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

Therefore, the deletion of this hill from Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 22.1m summit height and a 9.8m bwlch height, with these values giving this hill 12.4m 0f drop, which is insufficient for it to be classified as a Welsh Sub-P15. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Carnau 

OS 1:50,000 map:  114

Summit Height:  22.1m (LIDAR)                                                           

Summit Grid Reference:  SH 30392 76417 (LIDAR) 

Bwlch Height:  9.8m (LIDAR) 

Bwlch Grid Reference:  SH 30351 76179 & SH 30350 76178 (LIDAR) 

Drop:  12.4m (LIDAR) 

 

Myrddyn Phillips (September 2021)

 

 

 

 

  

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

 

Pt. 360.1m (SN 604 447) – Sub-Trichant reclassified to Trichant 

There has been confirmation of a reclassification to the list of Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail on contemporary maps produced from Ordnance Survey data and LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Pt. 360.1m (SN 604 447)

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

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

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

The hill is now listed by the Point (Pt. 360.1m) notation as an appropriate name for it either from historic research or local enquiry has not been found, and it is adjoined to the Elenydd group of hills, which are situated in the central part of the Mid and West Wales Region (Region B, Sub-Region B2), and it is positioned with a minor road to its north-east and the A482 road to its south-west, and has the town of Llanbedr Pont Steffan (Lampeter) towards the north-west. 

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

When the sub list was standardised and interpolated heights and drop values also included, the details for this hill were re-evaluated and it was listed with an estimated c 33m of drop, based on the 357m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 324m bwlch height, based on interpolation of 10m contouring between 320m – 330m that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.  

Therefore, the confirmation of the reclassification of this hill from Sub-Trichant status is due to detail on contemporary maps produced from Ordnance Survey data and LIDAR analysis, resulting in a 360.1m summit height and an estimated c 324m bwlch height, with these values giving this hill an estimated c 36m of drop, which is sufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Elenydd 

Name:  Pt. 360.1m 

OS 1:50,000 map:  146

Summit Height:  360.1m (LIDAR)                                                           

Summit Grid Reference:  SN 60451 44797 (LIDAR) 

Bwlch Height:  c 324m (interpolation) 

Bwlch Grid Reference:  SN 61574 45299 (interpolation) 

Drop:  c 36m (LIDAR summit and interpolated bwlch) 

 

Myrddyn Phillips (September 2021)

 

 

 

 

 

Wednesday 29 September 2021

Mapping Mountains – Significant Name Changes – The Welsh P15s


Plas (SH 350 772) 

There has been a Significant Name Change to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Plas (SH 350 772)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019. 

The Welsh P15s by Myrddyn Phillips

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 positioned with the coast to its west, the A5 road to its north, a minor road to its west and the A55 road to its south, and has the village of Gwalchmai towards the east south-east. 

When the listing that became known as The Welsh P15s was being compiled, this hill was listed under the point (Pt. 39m) notation with 15m of drop, based on the 39m summit spot height and the 24m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

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

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales. 

Extract from the Tithe map

The enclosed land where the summit of this hill is situated is given the number 16 on the Tithe map, this can be cross referenced against the apportionments; it is these apportionments that give the name of the owner or occupier of the land as well as the name of the land.  The land where the summit of this hill is situated is named as Plas in the apportionments, with the details on the Tithe map appearing in the parish of Llechylched and in the county named as Anglesey. 

Extract from the apportionments

Therefore, the name this hill is now listed by in The Welsh P15s is Plas and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Plas

Previously Listed Name:  Pt. 39m 

OS 1:50,000 map:  114

Summit Height:  37.4m (LIDAR)                                                           

Summit Grid Reference:  SH 35001 77280 (LIDAR) 

Bwlch Height:  22.6m (LIDAR) 

Bwlch Grid Reference:  SH 35405 77441 (LIDAR) 

Drop:  14.8m (LIDAR) 

 

Myrddyn Phillips (September 2021)

 

 

 

 

 

 

  

Mapping Mountains – Trimble Surveys – Gwaun Ceste

 

17.07.21  Hergest Ridge (SO 246 557), Hergest Ridge (SO 254 562, previously Trimbled) and Hanter Hill (SO 251 570, not Trimbled) 

The Welsh summit of Hergest Ridge (SO 246 557)

The main purpose of this walk was to visit and survey the Welsh summit of Hergest Ridge, which is now classified as a Pedwar under National Top status.  The concept of National Tops is explained in a separate post and for the lists co-authored with Aled Williams affects two hills, the other is Stonewall Hill (SO 318 696) which we visited and surveyed later in the day. 

This walk would also give opportunity to visit the English summit of Hergest Ridge and extend the walk across this hill’s broad summit ridge, to a point marked with a 417m spot height on contemporary Ordnance Survey maps and then also visit the Pedwar of Hanter Hill, with this and its higher neighbour separated at the connecting bwlch by the national border between Wales and England.  As the forecast gave for extremely warm conditions we needed a relatively early start to gain the majority of height before the heat of the day struck. 

We met in Caersŵs just before 8.00am and were parked and walking by 9.00am.  I had visited these hills once before in April 2015, on that occasion I had visited the higher English summit of Hergest Ridge, and not the Welsh summit, and although taking two data sets from the summit area of Hanter Hill, I failed to survey its actual summit, which we later found to be immersed in a mass of gorse. 

Approaching the hills from the west we followed a public footpath that starts as a track leading to Upper Hanter, which was once a farm.  It was already warm and any shaded area on the track proved a welcome relief from the conditions that would increase in ferocity as the day progressed. 

The public footpath leads past the front door of Upper Hanter before continuing as a green track through a gate and then onward through copious amounts of fern.  As we walked past the house we said our ‘hello’s’ to a woman sitting in shade reading.  We chatted for a few moments before waving our goodbyes and continuing up the hill. 

On the path leading to the bwlch between Hanter Hill and the English summit of Hergest Ridge

The greened path crept up hill giving good views of our first objective; the Welsh summit of Hergest Ridge, which from this viewpoint at this time of year shone green with upper slopes of fern, middle slopes consisting of grazing fields and mature trees as foreground, it looked a good hill and one which I had bi-passed when making an ascent from the south-west during my only other visit to the English summit of Hergest Ridge. 

The Welsh summit of Hergest Ridge

The green track eventually led to the connecting bwlch between Hanter Hill and Hergest Ridge; on one side of this bwlch is Wales and on the other, England.  On my previous visit a small conifer plantation was positioned just below the bwlch, this has now gone with the trees cut down. 

Hanter Hill from its connecting bwlch

The bwlch is also the meeting point of a number of tracks; we opted for the track leading to the English summit of Hergest Ridge, leaving Hanter Hill for later.  This ascent proved warm, with the left hand side of the track giving a semblance of shade.  Reaching a T-junction of tracks we then headed south-west loosing height as we did so, aiming for the Welsh summit and leaving the higher English summit until after. 

The new Pedwar is covered by LIDAR, which Aled and I had analysed.  The summit is close to a pool, which today was almost dry with just the last remaining vestiges of water giving some respite to the sheep who visited. 

LIDAR image of the Welsh summit of Hergest Ridge (SO 246 557)

The green track leads to within a few metres of this hill’s high point which consists of a small patch of gorse and fern.  The concept of National Tops was raised a few months ago and we had debated its merits and details on a number of occasions, having done so it was good to now be here standing on the Welsh summit of Hergest Ridge. 

Aled heading toward the Welsh summit of Hergest Ridge

We quickly assessed the lay of land and having decided its high point the Trimble was soon set-up gathering data.  During data collection Aled sat on the green track whilst I stood 50 or so metres away submerged in bracken.  Once allotted data were gathered and stored the equipment was closed down, packed away and I re-joined Aled on the green track and followed him back toward the higher English summit of Hergest Ridge. 

Gathering data at the Welsh summit of Hergest Ridge

The upper part of Hergest Ridge is open and any fences that exist are few and far between.  On a clear day the hill gives excellent walking on greened tracks with extensive views south to the distinctive profile of the Bannau Brycheiniog, east to the Clee Hills and Malvern Hills, and the higher Radnorshire hills to the west and north. 

It was a joy to be back on this hill; however conditions were decidedly warm and only on occasion did a welcome cooling breeze drift across its upper slopes.  We were soon on the higher summit which today had a number of horses beside it.  These slowly moved away as we made our way to the highest rock that constitutes the summit.  It was time for a rest and a bite to eat and the rocks proved an ideal place to sit and recuperate. 

The English summit of Hergest Ridge

We had no firm plan to visit the 417m map heighted top to the north-east, but as another track headed from close to its high point down to the connecting bwlch with Hanter Hill we decided to continue on the main ridge toward it. 

This top is crowned by nine monkey puzzle trees which are an unusual adornment for any summit at this altitude in this country.  Two benches are placed on their periphery and the larger gave another opportunity to sit and rest.  Just below the summit is the Whet Stone, which is marked on the map.  The stone is large, but is not Neolithic and in all likelihood found its way to its present position naturally. 

Monkey Puzzle trees at over 400m

From here it was only a short distance down the track to the bwlch between Hanter Hill and Hergest Ridge.  This bwlch has been Trimbled and LIDARed, therefore a second data set was unnecessary, however I hoped to take a data set from the true summit of Hanter Hill; something I failed to do on my previous visit. 

Hanter Hill from near the Whet Stone

The path leading up Hanter Hill proved a hot plod.  I watched as Aled quickly pulled ahead.  I paced myself going up, stopping once to take on water, look at the expanding view and to take a few photographs.  Soon I reached the hill’s summit area. 

On my previous visit I had taken two data sets from the summit area of Hanter Hill, neither of which matches the position of the summit produced by LIDAR.  This position is submerged in gorse.  As I recovered a modicum of breath I watched as Aled approached the gorse and headed in to it.  I soon followed but wearing shorts later emerged scratched and bloodied, with thorns still sticking in my legs. 

LIDAR image of Hanter Hill (SO 251 570)

When at the high point the gorse proved so dense that when I placed the Trimble on top of it, it remained in place.  Because of this I wondered about gathering data, but the thought of kneeling to take a measurement offset, coupled with four journeys in and out of the gorse waiting for the Trimble to achieve its 0.1m accuracy level before data should be locked and then waiting for allotted data to be gathered was enough to discourage me – LIDAR would suffice! 

The Trimble GeoXH 6000 at the summit of Hanter Hill

We now headed down to the bwlch and followed the green track of our ascent route back to Upper Hanter where the woman; Janet van der Linden, was still outside enjoying the morning’s shade.  We stopped and chatted, I joked that we had wondered if on our return we would be met with glasses of lemonade.  She smiled and went inside and brought out a jug of cold water with two glasses. 

A welcome sight; Janet with fresh chilled water

The water was refreshing and from a spring, it was very welcome.  We chatted about the old farm house and the route we had taken and where we were now heading.  This proved a much needed rest as even walking down hill in the increasing warmth proved tiring.  Having thanked Janet we headed down the continuation of the green track to the awaiting car and then headed northward toward Presteigne, where we stopped and replenished with goodies from the local Spar, before joining up with a narrow lane heading toward The Warren and Stonewall Hill, the latter our second Nation Top of the day. 

 

Postscript: 

Since the survey of these hills full LIDAR coverage is now available.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height and positional data that is now freely available for England and Wales.  Consequently the numerical details for these hills have been analysed using this technique, resulting in the LIDAR height and position for some of these hills being prioritised in preference to that produced by the Trimble GeoXH 6000.


Survey Result: 

 

Hergest Ridge

Summit Height:  401.0m (converted to OSGM15, Trimble GeoXH 6000) (Pedwar addition under National Top status)

Summit Grid Reference:  SO 24693 55769 (Trimble GeoXH 6000)

Bwlch Height:  269.5m (LIDAR)

Bwlch Grid Reference:  SO 22053 55707 (LIDAR)

Drop:  131.5m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  32.80% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

Hergest Ridge

Summit Height:  426.9m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Summit Grid Reference:  SO 25435 56259 (from previous Trimble GeoXH 6000 survey)

Col Height:  269.5m (LIDAR)

Col Grid Reference:  SO 22053 55707 (LIDAR)

Drop:  157.4m (Trimble GeoXH 6000 summit and LIDAR col)

Dominance:  36.88% (Trimble GeoXH 6000 summit and LIDAR col)

 

 

Hanter Hill

Summit Height:  415.0m (LIDAR)

Summit Grid Reference:  SO 25199 57096 (LIDAR)

Bwlch Height:  346.9m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Bwlch Grid Reference:  SO 25392 56820 (from previous Trimble GeoXH 6000 survey)

Drop:  68.1m (LIDAR summit and Trimble GeoXH 6000 bwlch)

Dominance:  16.41% (LIDAR summit and Trimble GeoXH 6000 bwlch)

 

 

For details on the survey of the English summit of Hergest Ridge and the bwlch survey of Hanter Hill


For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

 

 

Tuesday 28 September 2021

Mapping Mountains – Hill Reclassifications – The Welsh P15s


Plas (SH 350 772) – Welsh P15 reclassified to Welsh Sub-P15 

There has been a reclassification to the list of The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Plas (SH 350 772)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is listed by is Plas and this was derived from the Tithe map and it 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 positioned with the coast to its west, the A5 road to its north, a minor road to its west and the A55 road to its south, and has the village of Gwalchmai towards the east south-east. 

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main P15 list with 15m of drop, based on the 39m summit spot height and the 24m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

Therefore, the reclassification of this hill to Welsh Sub-P15 status is due to LIDAR analysis, resulting in a 37.4m summit height and a 22.6m bwlch height, with these values giving this hill 14.8m of drop, which is insufficient for it to be included in the main list of The Welsh P15s. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Plas 

OS 1:50,000 map:  114

Summit Height:  37.4m (LIDAR)                                                           

Summit Grid Reference:  SH 35001 77280 (LIDAR) 

Bwlch Height:  22.6m (LIDAR) 

Bwlch Grid Reference:  SH 35405 77441 (LIDAR) 

Drop:  14.8m (LIDAR) 

 

Myrddyn Phillips (September 2021)