Mapping Mountains – Significant Name Changes – 100m Twmpau

 

Y Lan (SN 283 229) 

There has been a Significant Name Change 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 Y Lan (SN 283 229)

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

The 100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Mynydd Pencarreg 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 and south and the B4299 road to its east, and has the small town of Sanclêr (St Clears) towards the south.

The hill appeared in the original Welsh 100m P30 list on Geoff Crowder’s v-g.me website, under the invented and transposed name of Allt Pantyrhedyn, with an accompanying note stating: Name from building to the North-West.

Allt Pantyrhedyn

188m

SN284229

145/158

177

Name from buildings to the North-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 put the word Allt in front of 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 316 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 Y Lan in the apportionments, with the details on the Tithe map appearing in the parish of Meidrim and in the county named as Carmarthenshire. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the 100m Twmpau is Y Lan, and this was derived from the Tithe map.                                                                  

The full details for the hill are:

Group:  Mynydd Pencarreg

Name:  Y Lan

Previously Listed Name:  Allt Pantyrhedyn   

OS 1:50,000 map:  145, 158

Summit Height:  188.0m (LIDAR) 

Summit Grid Reference:  SN 28371 22966 (LIDAR) 

Bwlch Height:  158.0m (LIDAR) 

Bwlch Grid Reference:  SN 28481 23410 & SN 28481 23413 (LIDAR) 

Drop:  29.97m (LIDAR) 

 

Myrddyn Phillips (July 2022)

 

 

 

 

 

 

 

 

 

 

Mapping Mountains – Hill Reclassifications – 100m Twmpau

Y Lan (SN 283 229) – 100m Twmpau reclassified to 100m Sub-Twmpau

There has been a reclassification to the list of 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 Y Lan (SN 283 229)

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

The 100m Twmpau by Myrddyn Phillips

The name the hill is now listed by is Y Lan and this was derived from the Tithe map, and it is adjoined to the Mynydd Pencarreg 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 and south and the B4299 road to its east, and has the small town of Sanclêr (St Clears) towards the south.

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 Hills to be surveyed sub list, as it was considered not to meet the criteria then used for the main P30 category.

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 30m of drop, based on the 188m summit spot height and the 158m bwlch spot height that appear 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.

Therefore, the reclassification of this hill to 100m Sub-Twmpau status is due to LIDAR analysis, resulting in a 188.0m summit height and a 158.0m bwlch height, with these values giving this hill 29.97m of drop, which is insufficient for it to be classified as a 100m Twmpau. 

 

The full details for the hill are: 

Group:  Mynydd Pencarreg 

Name:  Y Lan 

OS 1:50,000 map:  145, 158

Summit Height:  188.0m (LIDAR) 

Summit Grid Reference:  SN 28371 22966 (LIDAR) 

Bwlch Height:  158.0m (LIDAR) 

Bwlch Grid Reference:  SN 28481 23410 & SN 28481 23413 (LIDAR) 

Drop:  29.97m (LIDAR) 

 

Myrddyn Phillips (July 2022)

 

 

 

 

  

Mapping Mountains – Significant Name Changes – 200m Twmpau and Y Trechol – The Dominant Hills of Wales

 

Y Lan (SN 737 340) 

There has been a Significant Name Change to a hill that is listed in the 200m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Y Lan (SN 737 340)

The criteria for the two listings 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 200m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The hill appeared in the original Welsh 200m P30 list on Geoff Crowder’s v-g.me website, under the transposed name of Allt Ddu, which is a prominent name that appears north-west of the summit of this hill on the Ordnance Survey 1:25,000 Explorer map.

Allt Ddu

244m

SN739340

146

12/187

Clem/Yeaman. Trig pillar.

 

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, with the previously listed name of Allt Ddu applicable to land that does not take in the summit of this 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 455 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 Y Lan in the apportionments, with the details on the Tithe map appearing in the parish of Llandingad and in the county named as Carmarthen. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the 200m Twmpau and Y Trechol – The Dominant Hills of Wales is Y Lan and this was derived from the Tithe map. 

 

The full details for the hill are:

Group:  Mynydd Mallaen

Name:  Y Lan

Previously Listed Name:  Allt Ddu   

OS 1:50,000 map:  146, 160

Summit Height:  244.4m (LIDAR) 

Summit Grid Reference:  SN 73776 34010 (LIDAR) 

Bwlch Height:  135.75m (LIDAR) 

Bwlch Grid Reference:  SN 74333 34767 (LIDAR) 

Drop:  108.6m (LIDAR) 

Dominance:  44.45% (LIDAR) 

 

Myrddyn Phillips (March 2022)

 

 

 

 

Mapping Mountains – Summit Relocations – 200m Twmpau and Y Trechol – The Dominant Hills of Wales

 

Y Lan (SN 737 340) 

There has been a Summit Relocation to a hill that is listed in the 200m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Y Lan (SN 737 340)

The criteria for the two listings 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, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 200m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Y Lan and this was derived from the Tithe map, 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 minor roads to its north and west, the A482 road farther to its west and the A40 road to its south-east, and has the town of Llanymddyfri (Llandovery) towards the east. 

When the original Welsh 200m P30 list was published on Geoff Crowder’s v-g.me website, this hill was listed with a 244m summit height, based on the spot height adjoined to a triangulation pillar that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and which is positioned at SN 73903 33991. 

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 Y Lan (SN 737 340)

The summit height produced by LIDAR analysis is 244.4m and is positioned at SN 73776 34010, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are: 

The term Summit Relocations applies to when the high point is positioned in a different field, to a different feature such as a conifer plantation, within a different map contour, a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit 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 244.4m and this is positioned at SN 73776 34010, this position is not given a spot height on contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps, and is approximately 130 metres westward from where the previously listed summit is positioned.

 

The full details for the hill are:

Group:  Mynydd Mallaen

Name:  Y Lan

OS 1:50,000 map:  146, 160

Summit Height:  244.4m (LIDAR) 

Summit Grid Reference (New Position):  SN 73776 34010 (LIDAR) 

Bwlch Height:  135.75m (LIDAR) 

Bwlch Grid Reference:  SN 74333 34767 (LIDAR) 

Drop:  108.6m (LIDAR) 

Dominance:  44.45% (LIDAR) 

 

Myrddyn Phillips (March 2022)