Mapping Mountains – Hill Reclassifications – 700m Twmpau

Pt. 714.3m (SH 827 359) – 700m Sub-Twmpau addition

There has been an addition to the listing of the 700m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pt. 714.3m (SH 827 359)

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

700m Twmpau - Welsh hills at or above 700m and below 800m in height with 30m minimum drop, with an accompanying sub list entitled the 700m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 700m and below 800m 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 list is authored by Myrddyn Phillips and is available to download in Google Doc format from Mapping Mountains.

The 700m Twmpau by Myrddyn Phillips

The hill is being listed by the point (Pt. 714.3m) notation and it is adjoined to the Arenig Fawr group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A2), and it is positioned with a minor roads to the north, south-west and east, and the A4212 road farther to its north, and has the town of Y Bala towards the east.

When the list that later became known as the 700m Twmpau was first compiled, this hill was not included in the accompanying sub list due to an eye and spirit level survey conducted by John and Anne Nuttall that resulted in 60ft (18.3m) of drop, and it was originally listed with a 712m summit height based on the spot height that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and a 694m bwlch height. 

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 addition of this hill to 700m Sub-Twmpau status is due to LIDAR analysis, resulting in a 714.3m summit height and a 693.6m bwlch height, with these values giving this hill 20.7m of drop, which is sufficient for it to be classified as a 700m Sub-Twmpau.

 

The full details for the hill are:

Group:  Arenig Fawr

Name:  Pt. 714.3m

OS 1:50,000 map:  124, 125

Summit Height:  714.3m (LIDAR) 

Summit Grid Reference:  SH 82741 35938 (LIDAR) 

Bwlch Height:  693.6m (LIDAR) 

Bwlch Grid Reference:  SH 82725 36128 (LIDAR) 

Drop:  20.7m (LIDAR)

 

Myrddyn Phillips (July 2023)

 

 

  

Mapping Mountains – Hill Reclassifications – Y Pedwarau – The 400m Hills of Wales

Mynydd Fforest (SO 094 395) – 400m Pedwar reclassified to 390m Sub-Pedwar

There has been a reclassification to the listing of the Y Pedwarau – The 400m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from detail produced by Joe Nuttall in his surface analysis progamme, with subsequent LIDAR analysis conducted by the DoBIH team and independently by Aled Williams and Myrddyn Phillips. 

Mynydd Fforest (SO 094 395)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main Y Pedwarau list are five categories of sub hills, with this hill being reclassified to the 390m Sub-Pedwar category.  The criteria for this sub category being all Welsh hills at or above 390m and below 400m in height that have 30m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Mynydd Fforest and it is adjoined to the Mynydd Epynt group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its west, south and north-east, with the A470 road farther to its east, and has the village of Erwyd (Erwood) towards the north.

When the original 400m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a summit height of 400m, based on the spot height adjoined to the triangulation pillar that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map. 

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

After 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 63m of drop, based on the 400m summit spot height and an estimated c 337m bwlch height, based on interpolation of 10m contouring between 330m – 340m, and these were the values this hill was listed by when the 1^st edition of the Y Pedwarau was published by Europeaklist in May 2013. 

LIDAR summit image of Mynydd Fforest (SO 094 395)

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 from Pedwar status is due to LIDAR analysis, resulting in a 399.8m summit height and a 334.9m bwlch height, with these values giving this hill 65.0m of drop, with its height now sufficient for it to be classified as a 390m Sub-Pedwar. 

 

The full details for the hill are:

Group:  Mynydd Epynt 

Name:  Mynydd Fforest 

OS 1:50,000 map:  161

Summit Height:  399.8m (LIDAR) 

Summit Grid Reference:  SO 09495 39530 (LIDAR) 

Bwlch Height:  334.9m (LIDAR) 

Bwlch Grid Reference:  SO 07943 38253 (LIDAR) 

Drop:  65.0m (LIDAR)

 

For the additions, reclassifications and deletions to Y Pedwarau – The 400m Hills of Wales reported on Mapping Mountains since the May 2013 publication of the list by Europeaklist please consult the following Change Registers:

 

Y Pedwarau

 

Y Pedwarau – 400m Sub-Pedwarau

 

Y Pedwarau – 390m Sub-Pedwarau

 

Y Pedwarau – 390m Double Sub-Pedwarau

 

Myrddyn Phillips and Aled Williams (July 2023)

 

  

Mapping Mountains – Hill Reclassifications – Welsh Highlands – Uchafion Cymru

DUE TO A TRIMBLE GEOXH 6000 SURVEY THIS HILL HAS SUBSEQUENTLY BEEN REINSTATED TO WELSH HIGHLAND SUB STATUS

Pen Tyrau (SH 837 382) – Welsh Highland Sub deletion 

There has been a deletion to the listing of the Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Pen Tyrau (SH 837 382)

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

Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

Welsh Highlands - Uchafion Cymru by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Pen Tyrau, and it is adjoined to the Arenig Fawr group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A2), and it is positioned with a minor road and the A4212 road to its north, and has the town of Y Bala towards the east south-east.

When the initial P10 sub list was completed in June 2020 this hill was listed with 10.4m of drop, based on a basic levelling survey conducted by Myrddyn Phillips on the 14.09.98, and listed with a 697m summit height a 687m bwlch height, with an accompanying note stating that analysis of numerical data on various scales of Ordnance Survey maps give this hill an estimated c 9m of drop.  Therefore, it was included as a Welsh Highland Sub when the drop value of the subs was agreed upon and revised in July 2020. 

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 Highland Sub status is due to LIDAR analysis, resulting in a 697.8m summit height and a 688.1m bwlch height, with these values giving this hill 9.7m of drop, which is insufficient for it to be classified as a Welsh Highland Sub. 

 

The full details for the hill are: 

Group:  Arenig Fawr

Name:  Pen Tyrau

OS 1:50,000 map:  124, 125

Summit Height:  697.8m (LIDAR)

Summit Grid Reference:  SH 83744 38244 (LIDAR)

Bwlch Height:  688.1m (LIDAR)

Bwlch Grid Reference:  SH 83602 38147 (LIDAR)   

Drop:  9.7m (LIDAR) 

 

For the additions, deletions and reclassifications to the Welsh Highlands – Uchafion Cymru reported on Mapping Mountains please consult the following Change Registers:

 

Welsh Highland P15s

 

Welsh Highland Subs

 

Aled Williams and Myrddyn Phillips (July 2023)

 

  

Mapping Mountains – Significant Name Changes – 30-99m Twmpau

Field Above (SN 037 167) 

There has been a Significant Name Change to a hill that is listed in the 30-99m Twmpau, 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 Field Above (SN 037 167)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 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 30-99m Twmpau by Myrddyn Phillips

The hill is adjoined to the Mynydd Preseli group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north, west, south and east, and the A40 road farther to its south, and has the town of Hwlffordd (Haverfordwest) towards the west.

The hill appeared in the original Welsh 30-99m P30 list on Geoff Crowder’s v-g.me website, under the transposed and invented name of Colby Top, with an accompanying note stating; Name from farm to the South-West.

Colby Top

97m

SN038167

157/158

36

Name from farm to the South-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 transpose the name of a farm and add the word Top to it.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found.              

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 1145 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 Field Above in the apportionments, with the details on the Tithe map appearing in the parish of Cas-wis and in the county named as Pembroke. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the 30-99m Twmpau is Field Above, and this was derived from the Tithe map. 

 

The full details for the hill are:

Group:  Mynydd Preseli

Name:  Field Above

Previously Listed Name:  Colby Top 

OS 1:50,000 map:  157, 158

Summit Height:  96.6m (LIDAR) 

Summit Grid Reference:  SN 03767 16797 (LIDAR) 

Bwlch Height:  69.1m (LIDAR) 

Bwlch Grid Reference:  SN 03500 17359 (LIDAR) 

Drop:  27.5m (LIDAR) 

 

Myrddyn Phillips (July 2023) 

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

Coed Llwyn Owen (SN 703 403) – Sub-Trichant addition

There has been an addition 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. 

The criteria for the list that this addition 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 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

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

The name the hill is listed by is Coed Llwyn Owen and it is adjoined to the Mynydd Mallaen group of hills, which are situated in the central part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its and south and the A482 road farther to its south-west, and has the town of Llanymddyfri (Llandovery) towards the south-east.

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

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

After 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 20m of drop, based on the 346m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 326m bwlch height, based on interpolation of 10m contouring between 320m – 330m.

Therefore, the addition of this hill to Sub-Trichant status is due to detail on contemporary maps produced from Ordnance Survey data, resulting in a 346m summit height and an estimated c 326m bwlch height, with these values giving this hill an estimated c 20m of drop, which is sufficient for it to be classified as a Sub-Trichant. 

 

The full details for the hill are: 

Group:  Mynydd Mallaen 

Name:  Coed Llwyn Owen 

OS 1:50,000 map:  146, 147, 160

Summit Height:  346m (spot height)                                                           

Summit Grid Reference:  SN 70382 40319 (spot height) 

Bwlch Height:  c 326m (interpolation) 

Bwlch Grid Reference:  SN 70439 40313 (interpolation) 

Drop:  c 20m (spot height summit and interpolated bwlch) 

 

Myrddyn Phillips (July 2023)

 

  

Mapping Mountains – Trimble Surveys – Cefn yr Ystrad

 

06.06.23  Twyn yr Hyddod (SO 145 060) 

Twyn yr Hyddod (SO 145 060)

A day Pedwar bagging in the south Wales valleys with Mark, I started at a very leisurely pace with my head rested and eyes closed sitting in the front seat of my car whilst Mark visited the summit of Cadair Fawr (SN 977 123), a hill I had previously been up.  Although my eyes were closed for much of the time whilst I occasionally happily snoozed, I was still amazed at how fast cars seem to travel when passing a stationary object, they literally whizzed past on the minor road immediately in front of me as I opened an eye and stared out across a large expanse of grassland that disappeared toward the horizon with only the white flecks of a sheep or two to break the green monotony.

Once Mark was back from his first hill of the day he navigated us to the ridge above the Rhymni and Sirhywi valleys, it was here that the next two hills we planned on visiting were situated.  The first of which was Twyn yr Hyddod, which is a great bulk of a hill whose ascent is made easy if the convenience of its mountain road is taken, we took it, and I parked on the grass verge just below the high point of the road. 

Looking back toward the parking spot with the man-made hills of Twyn y Waun in the background on right

From the parking spot it was only a relatively short walk over copious amounts of bilberry up to the broad upper southerly ridge and then across to its crowning triangulation pillar.  However, before getting to the top I looked back beyond my car to the rows of terraced houses that make up the small community of Abertysswg, whose narrow road we had just driven on, on our way up the hill.  Beyond in the valley below were the houses of Rhymni and on the opposing side were the man-made hills of Twyn y Waun, which would be our last objective of the day. 

Approaching the summit of Twyn yr Hyddod

It was decidedly chilly on the ascent, so much so that when we reached the top Mark headed back down, leaving me to position the Trimble atop my rucksack and do all necessary things, such as noting the measurement offset between its internal antenna and the ground at its base and creating the file in the Trimble once the minimum of five satellites were logged on to.  All that remained was to wait until the 0.1m accuracy level was attained before data should be logged and then to stand back so as not to interfere with satellite reception whilst the allotted five minutes of data were gathered and stored.  During which I scribbled all necessary details in my surveying notebook. 

Gathering data at the summit of Twyn yr Hyddod

Once data were stored, I closed the equipment down, took a few photographs and packed it away and headed down, overshooting the direct descent which meant a slight double-back and a wander down the mountain road back to the car and the patiently waiting Mark, who was shielded from the chilled breeze whilst enjoying a bite to eat.  Twyn yr Hyddod proved a fine hill to start the day on. 

 

Survey Result:

 

Twyn yr Hyddod                       

Summit Height:  485.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 14515 06012 (Trimble GeoXH 6000)

Bwlch Height:  369.4m (LIDAR)

Bwlch Grid Reference:  SO 11880 10171 (LIDAR)

Drop:  116.2m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  23.93% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet