Mapping Mountains – Significant Name Changes – 200m Twmpau

 

Cae Cownog (SJ 111 135 & SJ 112 135) 

There has been a Significant Name Change to a hill that is listed in the 200m 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 Cae Cownog (SJ 111 135 and SJ 112 135)

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

200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The hill is adjoined to the Foel Cedig group of hills, which are situated in the central part of North Wales (Region A, Sub-Region A3), and it is positioned encircled by minor roads, with the B4393 road farther to its north, the B4382 road farther to its south-west and the A495 road farther to its south-east, and has the village of Meifod towards the east.

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

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 under the point (Pt. 212m) notation with 21m of drop, based on the 212m summit spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and the 191m 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 2107 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 Cae Cownog in the apportionments, with the details on the Tithe map appearing in the parish of Meifod and in the county named as Montgomery. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the 200m Twmpau is Cae Cownog, and this was derived from the Tithe map. 

 

The full details for the hill are:

Group:  Foel Cedig

Name:  Cae Cownog

Previously Listed Name:  Pt. 212m   

OS 1:50,000 map:  125

Summit Height:  212.5m (LIDAR) 

Summit Grid Reference:  SJ 11199 13511 & SJ 11200 13515 (LIDAR) 

Bwlch Height:  191.0m (LIDAR) 

Bwlch Grid Reference:  SJ 11120 13695 (LIDAR) 

Drop:  21.6m (LIDAR) 

 

Myrddyn Phillips (December 2024)

 

 

 

 

 

 

Mapping Mountains – Hill Reclassifications – The Welsh P15s

 

Y Dinas Ucha (SH 818 826) – Welsh 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 Y Dinas Ucha (SH 818 826)

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 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is now listed by is Y Dinas Ucha and this was derived from the Tithe map, and it is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned with the coast to its immediate north-east and the B5115 road to its south-west, and has the town of Llandudno towards the west.

When the listing that became known as The Welsh P15s was being compiled, this hill was included in the main list with an estimated c 15m of drop, based on an estimated c 42m summit height and an estimated c 27m bwlch height, with both heights based on interpolation of 5m contouring. 

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 P15 status is due to LIDAR analysis, resulting in a 41.8m summit height and a 28.2m bwlch height, with these values giving this hill 13.6m 0f drop, which is insufficient for it to be classified as a Welsh P15. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Y Dinas Ucha 

OS 1:50,000 map:  116

Summit Height:  41.8m (LIDAR)                                                           

Summit Grid Reference:  SH 81890 82674 (LIDAR)                                                  

Bwlch Height:  28.2m (LIDAR) 

Bwlch Grid Reference:  SH 81903 82535 (LIDAR) 

Drop:  13.6m (LIDAR) 

 

Myrddyn Phillips (December 2024)

 

 

 

Mapping Mountains – Summit Relocations – 100m Twmpau

 

Cae (SN 560 038) 

There has been a Summit Relocation to a hill that is listed in the 100m 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 Cae (SN 560 038)

The criteria for the list that this summit relocation applies to are:

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 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.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Mynydd Sylen group of hills, which are situated in the southern part of South Wales (Region B, Sub-Region B5), and it is positioned between the stream valleys of the Afon Morlais to its west and the Afon Gwili to its east, and has the towns of Llanelli to the south-west and Pontarddulais to the east.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the main P30 list with a 119m summit height, based on the spot height that appears at SN 56057 03826 on the contemporary Ordnance Survey 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-assessed and it was listed with an estimated c 39m of drop, based on the 118m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, and an estimated c 79m bwlch height, based on interpolation of 5m contouring between 75m – 80m.

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 analysis gives the highest ground on this hill as 119.9m positioned at SN 56063 03818.  However, this is to the top of a raised field boundary and protocols dictate that as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill. 

LIDAR summit image of Cae (SN 560 038)

The height produced by LIDAR analysis to the natural summit of this hill is 119.0m and is positioned at SN 56069 03819, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is judged to be a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the height produced by LIDAR analysis to the natural summit of this hill is 119.0m and is positioned at SN 56069 03819, this is relatively close to where the spot height appears, and is approximately six metres eastward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Sylen 

Name:  Cae 

OS 1:50,000 map:  159

Summit Height:  119.0m (LIDAR)               

Summit Grid Reference (New Position):  SN 56069 03819 (LIDAR) 

Bwlch Height:  80.0m (LIDAR) 

Bwlch Grid Reference:  SN 55961 04021 (LIDAR) 

Drop:  39.0m (LIDAR) 

 

Myrddyn Phillips (December 2024)

 

 

  

Mapping Mountains – Trimble Surveys – Crib Goch

 

05.10.24  Crib Goch (SH 624 551), Pt. 914.6m (SH 623 551), Pt. 901.8m (SH 622 551), Pt. 906.2m (SH 619 551), Pt. 563.0m (SH 638 551) and Carreg Gwalch (SH 642 552) 

The early birds had already gathered at Pen y Pàs, but pure thriftiness, or perhaps self-imposed meanness, had destined my course past them for a lower starting point near the bottom of Bwlch Llanberis.  As I wearily stumbled out of the car, I spotted lights up on the darkened skyline as an even earlier bird traversed along the north ridge of Crib Goch.  This mountain was the primary surveying objective for the day. 

Sunrise.  Photo: Aled Williams

A steep ascent was tempered by scenes of sunrise, with the silhouette of a cloud-capped Moel Siabod beautifully framed by the walls of Y Pàs, its narrow road conspicuously snaking up the valley below.  Periodic rests allowed me to appreciate the ruggedness of these mountains, vast slopes riddled with rock features of various character.  I marvelled at these being the workplaces of the shepherds, the true “mountain men”. 

Base of the north ridge.  Photo: Aled Williams

I had now arrived at the base of the north ridge.  A fair-weather day had been promised but with 30mph wind speeds and these were most definitely present with occasional blusterier spells.  As I ventured onto the start of the arete, I took note of the greasy rocks, not yet dried from the dampening effects of the overnight mists.

The lower arete.  Photo: Aled Williams

Before continuing further I decided to prepare myself for surveying, in case the winds made it difficult to retrieve the various pieces of equipment whilst on the ridge.  The downside of this was that the collection of objects hanging around my neck and stuffed into pockets restricted movement and tended towards imbalance!  I would have to take the traverse carefully and slowly. 

The upper arete.  Photo: Aled Williams

Despite a few uncomfortable blasts from the wind, the ascent of the north ridge went by without incident and I soon found myself at the eastern end of the summit arete, where a few flocks of those early birds were resting having ascended via the east ridge.  I decided that it would be best to go on before them, thus giving me the opportunity to set up the Trimble GeoXH 6000 while they traversed past me, meaning that data collection could then occur without interference from passers-by. 

The summit arete.  Photo: Aled Williams

My memory of the highest point was thankfully incorrect and it proved a relatively sheltered and safe position to spend what would otherwise be a disproportionate amount of time on such an airy summit.  I immediately started to collect 5 minutes of data once the first group of people passed by and was not interrupted by others.  I packed away the equipment happy with the thought that the summit of Crib Goch had now been surveyed. 

Surveying the summit of Crib Goch.  Photo: Aled Williams

The next objective was to survey the bwlch and then the summit of the highest of Crib Goch’s famous pinnacles.  Both points were easily surveyed, with an Abney level being used to locate the highest spike of rock atop the pinnacle. 

A window on the world.  Photo: Aled Williams

As I packed away the equipment atop the highest pinnacle, numerous groups were now making their way along the summit arete.  It was getting busier and this would make surveying the lowest of the pinnacles very difficult. 

The highest of the pinnacles.  Photo: Aled Williams

The problem became apparent once I arrived at the bwlch of the lowest pinnacle.  Its position was a nick between two rocks, exactly at the start of the easiest route that allows passage up and over the pinnacle.  The best approach was to survey it in a time window between the groups of people.  Unfortunately, the tight confines of the bwlch impacted the Trimble’s ability to reach its required accuracy level for measurement.  Just as it was close to reaching this level, a group of people would pass and it would shoot back up to inaccurate levels again! 

The problematic tight bwlch of the lower pinnacle.  Photo: Aled Williams

After a frustrating 45 minutes at the bwlch, data was eventually collected.  I quickly scrambled to the top of the lowest pinnacle and located the highest spike of rock through use of an Abney level.  In contrast, this survey went smoothly and within 10 minutes it had been completed. 

Surveying the summit of the lowest pinnacle.  Photo: Aled Williams

I descended to Bwlch Coch and headed straight to the bwlch of the next top to be surveyed (Pt. 906.2m at SH 619 551).  This was formerly listed as a Welsh Highlands Sub, but was deleted in March 2023 following LIDAR analysis that gave the top only 9.8m of drop.  Given the highly marginal nature of the LIDAR result, this was a priority survey to complete. 

The bwlch of Pt. 906.2m.  Photo: Aled Williams

As the Trimble gathered data, I sat on the grassy edge looking down to Cwmglas Mawr.  The vista of lakes and peaks beyond was stunning, as was the one behind me of Clogwyn y Garnedd and Lliwedd.  A short walk along the narrow ridge of the top brought me to the summit rocks and the Trimble was duly positioned for 5 minutes of measurement. 

Surveying the summit of Pt. 906.2m.  Photo: Aled Williams

After packing up the equipment I headed back to Bwlch Coch, taking the unpleasantly steep descent to Llwybr Pyg during the height of the midday heat.  My final objectives of the day were two Welsh Highland Subs found on the ridge between Bwlch y Moch and Pen y Pàs: Pt. 563.3m and Carreg Gwalch.  These surveys were completed efficiently with not a single walker met along the entire length of the pleasant undulating ridge that joins the two tops together.  All that remained of an excellent day’s surveying was the long plod back to the car.

Pt. 563.0m and Carreg Gwalch.  Photo: Aled Williams.

Survey Result: 

 

Crib Goch

Summit Height:  924.0m (converted to OSGM15, Trimble GeoXH 6000) (average of three surveys)

Summit Grid Reference:  SH 62418 55182 (Trimble GeoXH 6000)

Bwlch Height:  857.2m (LIDAR)

Bwlch Grid Reference:  SH 62168 55116 (LIDAR)

Drop:  66.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  7.23% (Trimble GeoXH 6000 summit and LIDAR bwlch)  

 

 

Pt. 914.6m

Summit Height:  914.6m (converted to OSGM15)

Summit Grid Reference:  SH 62309 55153

Bwlch Height:  904.1m (converted to OSGM15)

Bwlch Grid Reference:  SH 62336 55149

Drop:  10.6m

Dominance:  1.16%

 

 

Pt. 901.8m

Summit Height:  901.8m (converted to OSGM15)

Summit Grid Reference:  SH 62258 55130

Bwlch Height:  892.5m (converted to OSGM15, Trimble GeoXH 6000)

Bwlch Grid Reference:  SH 62268 55133 (LIDAR)

Drop:  9.3m

Dominance:  1.03%

 

 

Pt. 906.2m

Summit Height:  906.2m (converted to OSGM15)

Summit Grid Reference:  SH 61983 55146

Bwlch Height:  896.1m (converted to OSGM15)

Bwlch Grid Reference:  SH 61885 55154

Drop:  10.1m (Welsh Highland Sub Reinstatement)

Dominance:  1.11%

 

 

Pt. 563.0m

Summit Height:  563.0m (converted to OSGM15)

Summit Grid Reference:  SH 63821 55162

Bwlch Height:  552.8m (converted to OSGM15)

Bwlch Grid Reference:  SH 63750 55175

Drop:  10.2m (Welsh Highland Sub addition)

Dominance:  1.82%

 

 

Carreg Gwalch

Summit Height:  546.0m (converted to OSGM15)

Summit Grid Reference:  SH 64238 55249

Bwlch Height:  531.2m (converted to OSGM15)

Bwlch Grid Reference:  SH 64229 55166

Drop:  14.7m (Welsh Highland Sub addition)  

Dominance:  2.70%

 

 

For further details please consult the Trimble Survey Spreadsheet