Mapping Mountains – Significant Name Changes – The Welsh P15s

 

Maes Llwyn (SH 435 920) 

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 Maes Llwyn (SH 435 920)

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 10^th 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 north and is encircled by minor roads with the B5111 road and the A5025 road farther to its north and also east, and has the town of Amlwch towards the north-east. 

When the listing that became known as The Welsh P15s was being compiled, this hill was listed under the point (Pt. 77m) notation with 25m of drop, based on the 77m summit spot height positioned on or near to a covered reservoir, that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the 52m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger 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 216 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 Maes Llwyn in the apportionments, with the details on the Tithe map appearing in the parish of Amlwch 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 Maes Llwyn and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Maes Llwyn

Previously Listed Name:  Pt. 77m 

OS 1:50,000 map:  114

Summit Height:  74.0m (LIDAR) 

Summit Grid Reference:  SH 43593 92022 (LIDAR) 

Bwlch Height:  54.9m (LIDAR) 

Bwlch Grid Reference:  SH 43658 91747 (LIDAR) 

Drop:  19.1m (LIDAR) 

 

Myrddyn Phillips (September 2021)

 

 

 

 

 

 

 

 

Mapping Mountains – Summit Relocations – The Welsh P15s

 

Maes Llwyn (SH 435 920) 

There has been a Summit Relocation to a hill that is listed in the 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 Maes Llwyn (SH 435 920)

The criteria for the list that this summit relocation 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 listed by is Maes Llwyn 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 north and is encircled by minor roads with the B5111 road and the A5025 road farther to its north and also east, and has the town of Amlwch towards the north-east. 

When the listing that became known as The Welsh P15s was being compiled, this hill was listed with 25m of drop, based on the 77m summit spot height positioned at SH 43598 92043 on or near to a covered reservoir, that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the 52m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger 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 Maes Llwyn (SH 435 920)

The height produced by LIDAR analysis to a remaining natural summit is 74.0m and is positioned at SH 43593 92022, 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 hill’s high point is found to be positioned; in a different field, within a different map contour, to a different feature such as in a conifer plantation, to a different point where a number of potential summit positions are within close proximity, 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, or when natural ground or the natural and intact summit is confirmed compared to a higher point such as a raised field boundary that is judged to be a relatively recent man-made construct. 

Therefore, the summit height produced by LIDAR analysis is 74.0m and this is positioned at SH 43593 92022, 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 20 metres southward from where the 77m spot height appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Maes Llwyn 

OS 1:50,000 map:  114

Summit Height:  74.0m (LIDAR) 

Summit Grid Reference (New Position):  SH 43593 92022 (LIDAR) 

Bwlch Height:  54.9m (LIDAR) 

Bwlch Grid Reference:  SH 43658 91747 (LIDAR) 

Drop:  19.1m (LIDAR) 

 

Myrddyn Phillips (September 2021)

 

 

 

 

Mapping Mountains – Significant Height Revisions – The Welsh P15s

Maes Llwyn (SH 435 920) 

There has been a Significant Height Revision 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 Maes Llwyn (SH 435 920)

The criteria for the list that this height revision 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 listed by is Maes Llwyn 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 north and is encircled by minor roads with the B5111 road and the A5025 road farther to its north and also east, and has the town of Amlwch towards the north-east. 

When the listing that became known as The Welsh P15s was being compiled, this hill was listed with 25m of drop, based on the 77m summit spot height positioned on or near to a covered reservoir that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the 52m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger 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 Maes Llwyn

The height produced by LIDAR analysis to a remaining natural summit is 74.0m and 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 or Harvey 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 to the data produced by the Trimble or by LIDAR analysis. 

Therefore, this hill’s new listed summit height is 74.0m and this was derived from LIDAR analysis, this is 3m lower than the previous listed summit height of 77m which was based on the spot height positioned on or near to a covered reservoir that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Ynys Môn 

Name:  Maes Llwyn 

OS 1:50,000 map:  114

Summit Height (New Height):  74.0m (LIDAR) 

Summit Grid Reference:  SH 43593 92022 (LIDAR) 

Bwlch Height:  54.9m (LIDAR) 

Bwlch Grid Reference:  SH 43658 91747 (LIDAR) 

Drop:  19.1m (LIDAR) 

 

Myrddyn Phillips (September 2021)

 

 

 

 

 

 

  

Mapping Mountains – Hill Reclassifications – 30-99m Twmpau

Maes Llwyn (SH 435 920) – 30-99m Sub-Twmpau deletion

There has been a deletion to the list of 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 Maes Llwyn (SH 435 920)

The criteria for the list that this deletion 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 name the hill is listed by is Maes Llwyn 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 north and is encircled by minor roads with the B5111 road and the A5025 road farther to its north and also east, and has the town of Amlwch towards the north-east. 

When the original 30-99m 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. 

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 25m of drop, based on the 77m summit spot height positioned on or near to a covered reservoir that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and the 52m bwlch spot height that appears on the Ordnance Survey 1:50,000 Landranger 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 30-99m Sub-Twmpau status is due to LIDAR analysis, resulting in a 74.0m height to a natural summit and a 54.9m bwlch height, with these values giving this hill 19.1m of drop, which is insufficient for it to be classified as a 30-99m Sub-Twmpau. 

 

The full details for the hill are: 

Group:  Ynys Môn 

Name:  Maes Llwyn 

OS 1:50,000 map:  114

Summit Height:  74.0m (LIDAR) 

Summit Grid Reference:  SH 43593 92022 (LIDAR) 

Bwlch Height:  54.9m (LIDAR) 

Bwlch Grid Reference:  SH 43658 91747 (LIDAR) 

Drop:  19.1m (LIDAR) 

 

Myrddyn Phillips (August 2021)