Myrddyn Phillips - Mapping Mountains: Morben Mawr

Showing posts with label Morben Mawr. Show all posts

Monday, 19 April 2021

Mapping Mountains – Significant Name Changes – 100m Twmpau

Morben Mawr (SN 712 990)

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 confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Morben Mawr (SN 712 990)

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 with 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 Banc Llechwedd Mawr group of hills, which are situated in the north-western part of South Wales (Region B, Sub-Region B1), and it has the A487 road to its north and west, and a minor road to its immediate south-east, and has the town of Machynlleth towards the north north-east.

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

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was listed under the invented and transposed name of Mynydd Morben, with an accompanying note stating; Name from hall and farm to the North.

Mynydd Morben

100c

SN712990

135

Name from hall and farm 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. 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 near hall and farm and prefix it with the word Mynydd. 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.

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 928 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 a part of Morben Mawr in the apportionments, with the details on the Tithe map appearing in the parish of Machynlleth and in the county named as Montgomery.

Extract from the apportionments

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

The full details for the hill are:

Group: Banc Llechwedd Mawr

Name: Morben Mawr

Previously Listed Name: Mynydd Morben

OS 1:50,000 map: 135

Summit Height: 104.6m (LIDAR)

Summit Grid Reference: SN 71208 99001 (LIDAR)

Bwlch Height: 73.1m (LIDAR)

Bwlch Grid Reference: SN 71490 98974 & SN 71489 98977 (LIDAR)

Drop: 31.5m (LIDAR)

Myrddyn Phillips (April 2021)

Friday, 9 April 2021

Mapping Mountains – Hill Reclassifications – 100m Twmpau

Morben Mawr (SN 712 990) – 100m Sub-Twmpau reclassified to 100m Twmpau

There has been confirmation of a reclassification to the list of 100m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis conducted by Myrddyn Phillips.

LIDAR image of Morben Mawr (SN 712 990)

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 listed by is Morben Mawr and this was derived from the Tithe map, and it is adjoined to the Banc Llechwedd Mawr group of hills, which are situated in the north-western part of South Wales (Region B, Sub-Region B1), and it has the A487 road to its north and west, and a minor road to its immediate south-east, and has the town of Machynlleth towards the north north-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 Hills to be surveyed sub list that accompanied the main P30 list, as it was considered not to meet the criteria then used for the main P30 category.

When 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 25m of drop, based on an estimated c 102m summit height and an estimated c 177m bwlch height, both heights based on interpolation of 10m contouring that appear on the Ordnance Survey 1:25,000 Explorer map.

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

The details for this hill we re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online. This mapping had many spot heights not on other publicly available Ordnance Survey maps and for this hill a 104m spot height was given on the area of its summit and with a re-appraisal of its estimated bwlch height to c 74m, these values gave this hill an estimated c 30m of drop.

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 confirmation of the reclassification of this hill from 100m Sub-Twmpau status is due to LIDAR analysis, resulting in a 104.6m summit height and a 73.1m bwlch height, with these values giving this hill 31.5m of drop, which is sufficient for it to be classified as a 100m Twmpau.