Mapping Mountains – Significant Name Changes – 200m Twmpau

Cae Gwar y Tŷ (SO 035 495) 

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 Gwar y Tŷ (SO 035 495)

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 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 and immediate east, and the B4520 road farther to its east, and has the town of Llanfair-ym-Muallt (Builth Wells) towards the north.

When the original 200m 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 under the transposed name of Cnwc-y-llo, with an accompanying note stating; Name from buildings to the North.

Cnwc-y-llo

235m

SO035495

147

188

Name from buildings to the North

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, with little consideration for the meaning of the name and where it was appropriately applied to.  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 use it for that of the hill.  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 226 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 Gwar y Tŷ in the apportionments, with the details on the Tithe map appearing in the parish named as Builth and in the county named as Brecon. 

Extract from the apportionments

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

 

The full details for the hill are:

Group:  Mynydd Epynt

Name:  Cae Gwar y Tŷ

Previously Listed Name:  Cnwc-y-llo   

OS 1:50,000 map:  147

Summit Height:  232.8m (LIDAR) 

Summit Grid Reference:  SO 03502 49537 & SO 03504 49535 (LIDAR) 

Bwlch Height:  198.4m (LIDAR) 

Bwlch Grid Reference:  SO 03391 49083 (LIDAR) 

Drop:  34.4m (LIDAR) 

 

Myrddyn Phillips (February 2025)

 

 

 

  

Mapping Mountains – Summit Relocations – 200m Twmpau

 

Cae Gwar y Tŷ (SO 035 495) 

There has been a Summit Relocation 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 Gwar y Tŷ (SO 035 495)

The criteria for the list that this summit relocation 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 name the hill is now listed by is Cae Gwar y Tŷ, and this was derived from the Tithe map, 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 and immediate east, and the B4520 road farther to its east, and has the town of Llanfair-ym-Muallt (Builth Wells) towards the north.

When the original 200m 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 235m summit height, based on the spot height that appears on 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 37m of drop, based on the 235m summit spot height positioned at SO 03503 49545 and the 198m bwlch spot height 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

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 232.84m positioned at SO 03504 49538.  However, this is a part 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 Gwar y Tŷ (SO 035 495)

The height produced by LIDAR analysis to the natural summit of this hill is 232.81m and this is positioned at SO 03502 49537 and SO 03504 49535, 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 either on Ordnance Survey maps or interactive mapping, 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 considered 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 summit height produced by LIDAR analysis is 232.81m and this is positioned at SO 03502 49537 and SO 03504 49535, and this position is approximately three metres west south-westward from the high point of the raised field boundary. 

 

The full details for the hill are: 

Group:  Mynydd Epynt 

Name:  Cae Gwar y Tŷ                  

OS 1:50,000 map:  147

Summit Height:  232.8m (LIDAR) 

Summit Grid Reference (New Position):  SO 03502 49537 & SO 03504 49535 (LIDAR) 

Bwlch Height:  198.4m (LIDAR) 

Bwlch Grid Reference:  SO 03391 49083 (LIDAR) 

Drop:  34.4m (LIDAR) 

 

Myrddyn Phillips (February 2025)

 

Mapping Mountains – Significant Height Revisions – 200m Twmpau

Cae Gwar y Tŷ (SO 035 495) 

There has been a Significant Height Revision 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 Gwar y Tŷ (SO 035 495)

The criteria for the list that this height revision 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Cae Gwar y Tŷ, and this was derived from the Tithe map, 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 and immediate east, and the B4520 road farther to its east, and has the town of Llanfair-ym-Muallt (Builth Wells) towards the north.

When the original 200m 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 235m summit height, based on the spot height that appears on 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 37m of drop, based on the 235m summit spot height and the 198m bwlch spot height 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

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 Cae Gwar y Tŷ (SO 035 495)

LIDAR analysis gives the summit of this hill as 232.8m positioned at SO 03502 49537 and SO 03504 49535, and when compared to its originally listed summit height of 235m this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey, Harvey or other interactive map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR.  Also included are hills whose summit map data is missing an uppermost ring contour when compared with the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 232.8m and this was derived from LIDAR analysis, this is 2.2m lower than the originally listed summit height of 235m, which was based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map.

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Mynydd Epynt 

Name:  Cae Gwar y Tŷ 

OS 1:50,000 map:  147

Summit Height (New Height):  232.8m (LIDAR) 

Summit Grid Reference:  SO 03502 49537 & SO 03504 49535 (LIDAR) 

Bwlch Height:  198.4m (LIDAR) 

Bwlch Grid Reference:  SO 03391 49083 (LIDAR) 

Drop:  34.4m (LIDAR) 

 

Myrddyn Phillips (February 2025)

 

 

  

Mapping Mountains – Trimble Surveys – Mynydd Epynt

 

02.11.24  Cae Gwar y Tŷ (SO 035 495) 

LIDAR image of Cae Gwar y Tŷ (SO 035 495)

Today, Charles and I attended the funeral of Moira Brown in Builth Wells.  Moira was married to Iain for 54 years, and as well as showing our respect to Moira it was also a gesture of support on our part to Iain, who for many years was a stalwart of the hill bagging community.  After the funeral we gathered in the Greyhound Hotel for food and conversation.

Before heading back to Welshpool we ventured to the hills.  Over the last week a high pressure system had been firmly stuck over the country, giving settled, albeit grey skies with little direct sunshine.  Such conditions can give cloud inversions on the higher hills, but can also give murky conditions with cloud nestled on the lower hills.  We planned on doing two small walks, with our second walk taking in a hill listed as a Pedwar, which is in the 400m height band, and thankfully on our approach to Builth all such hills were clear of cloud.  Our first walk took in a hill lower in height and with only a slight diversion on a narrow lane; it was on our way to the higher hill. 

Just sufficient space off the narrow lane not to obstruct other vehicles

The Tithe map gives the name of the field where the high point of this hill is situated as Cae Gwar y Tŷ.  A fine field name and one that is appropriate to use for listing purposes.  We wanted as quick an ascent as possible as daylight hours were quickly fading, therefore having LIDAR’ed the hill I decided that although I had the Trimble, I would forgo surveying its summit. 

Charles approaching the summit

The high point of the hill is positioned close to a minor road and in the main protected from any direct ascent from its east by hedges.  However, there is now a copse of woodland that stretches from the lane adjacent to grazing fields toward its summit.  The entrance to the woodland is open and opposite there is just enough space to pull a car off the lane on to the grass verge.  This was our starting point. 

The Trimble GeoXH 6000 positioned at the summit of Cae Gwar y Tŷ

It only took a few minutes to get our gear together and enter the wood.  Low branches were avoided as we made our way through and between the trees, and we were soon straddling the low hung barb wired fence and standing on the summit of the hill. 

Charles beside the Larch tree near the summit

Although not planning to Trimble the summit I set the equipment up on my rucksack to at least take a few photos of it.  During this Charles headed in to the wood for our descent, but before heading down, he stood beside an elegantly coloured Larch tree for the customary autumnal photograph. 

Heading down through the wood to the lane below

All that remained was the walk back through the wood to the awaiting car, avoiding any low hanging branches on our way.  It had taken seven minutes to visit this hill and that included taking a number of photographs whilst on or near the summit. 

 

Survey Result:

 

Cae Gwar y Tŷ (significant name change)      

Summit Height:  232.8m (LIDAR) (significant height revision)

Summit Grid Reference:  SO 03502 49537 & SO 03504 49535 (LIDAR) (summit relocation)

Col Height:  198.4m (LIDAR)

Col Grid Reference:  SO 03391 49083 (LIDAR)

Drop:  34.4m (LIDAR)

Dominance:  14.786% (LIDAR) 

 

 

For further details please consult the Trimble Survey Spreadsheet