Mapping Mountains – Hill Reclassifications – 30-99m Twmpau

Cae Doctor (SH 304 399) – 30–99m Sub-Twmpau reclassified to 30-99m Twmpau

There has been confirmation of a Hill Reclassification to the list of 30-99m Twmpau, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, with the bwlch LIDAR analysis initially conducted by Aled Williams, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 3^rd October 2018.

The summit of Cae Doctor (SH 304 399)

The criteria for the list that this reclassification applies to are:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 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.

When the original Welsh 30-99m height band of P30 hills were published on Geoff Crowder’s v-g.me website this hill appeared in the accompanying Hills to be surveyed sub list as it did not meet the criteria then used for the main P30 list; however this sub list has now been standardised with drop values and interpolated heights also included in the main P30 and the accompanying sub list.

When this list was standardised with interpolated heights and drop values included this hill was listed with an estimated c 30m of drop based on the 68m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 38m based on interpolation of 10m bwlch contouring.

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

The details for this hill were reassessed when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online, and this map has a 37m spot height positioned at SH 30870 40378 on a minor road on the area of this hill’s bwlch, and if taken as a part of this hill’s drop this would give a value of 31m.

The locally known name for the bounded land where the summit of this hill is situated is Cae Doctor, and this is the name the hill is now listed by.  The hill is adjoined to the Pen Llŷn group of hills, which are situated in the western part of North Wales (Region A, Sub-Region A1), and it has the A497 road to its immediate south-east and the B4417 road to its north-west, and has the small town of Nefyn to the north.

The confirmation of the reclassification of Cae Doctor to 30-99m Twmpau status is due to LIDAR analysis of the bwlch conducted by Aled Williams and a summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, resulting in a 67.0m summit height and a 35.8m bwlch height, with these values giving this hill 31.2m of drop which is sufficient for it to be classified as a 30-99m Twmpau.

The Trimble GeoXH 6000 gathering data at the summit of Cae Doctor (SH 304 399)

The full details for the hill are:

Group:  Pen Llŷn

Name:  Cae Doctor

OS 1:50,000 map:  123

Summit Height:  67.0m (converted to OSGM15)

Summit Grid Reference:  SH 30425 39978

Bwlch Height:  35.8m (LIDAR)

Bwlch Grid Reference:  SH 30747 40107 (LIDAR)

 

Drop:  31.2m (Trimble summit and LIDAR bwlch)

My thanks to Aled Williams for initial LIDAR analysis of this hill’s bwlch

For details of the summit survey of this hill

Myrddyn Phillips (February 2019)

Mapping Mountains – Significant Name Changes – 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales

Cae Doctor (SH 304 399)

There has been a Significant Name Change to a hill that is listed in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales, with the summit height, its location, the drop and status of the hill confirmed by LIDAR analysis, with the bwlch LIDAR analysis initially conducted by Aled Williams, and a subsequent summit survey with the Trimble GeoXH 6000 conducted by Myrddyn Phillips, with the latter taking place on the 3^rd October 2018.

The summit of Cae Doctor (SH 30425 39978)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 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.

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, with the Introduction to the Mapping Mountains publication of this list appearing on the 3^rd December 2015.

The hill is adjoined to the Pen Llŷn group of hills, which are situated in the western part of North Wales (Region A, Sub-Region A1), and it has the A497 road to its immediate south-east and the B4417 road to its north-west, and has the small town of Nefyn to the north.

This hill was first listed in the Hills to be surveyed sub-list that accompanied the original Welsh 30-99m P30 list published on Geoff Crowder’s v-g.me website, under the invented name of Fron Oleu, with an accompanying note stating; Name from buildings to the South-West.

Fron Oleu

68m

SH305400

123

253

Name from buildings to the South-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 buildings that are situated near 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

I visited this hill along with Aled Williams and leaving the summit we met the local farmer who had driven up a near track to find out what we were doing.  Having explained our interest in surveying and upland place-names, Awen Roberts told us that the hill does not have an individual name but the two fields that vie for the high point of this hill are known as Cae Doctor (67.0m at SH 30425 39978) and Cae Myllt (66.9m at SH 30421 39985), with the former the higher and being named as such as a doctor lives close to its field boundary.

The summit of Cae Myllt (SH 30421 39985)

Therefore, the name this hill is now listed by in the 30-99m Twmpau and Y Trechol – The Dominant Hills of Wales is Cae Doctor, and this was derived from local enquiry.

The full details for the hill are:

Group:  Pen Llŷn

Name:  Cae Doctor

Previously Listed Name:  Fron Oleu

 

OS 1:50,000 map:  123

Summit Height:  67.0m (converted to OSGM15)

Summit Grid Reference:  SH 30425 39978

Bwlch Height:  35.8m (LIDAR)

Bwlch Grid Reference:  SH 30747 40107 (LIDAR)

 

Drop:  31.2m (Trimble summit and LIDAR bwlch)

Dominance:  46.59% (Trimble summit and LIDAR bwlch)

My thanks to Aled Williams for initial LIDAR analysis of this hill’s bwlch

For details of the summit survey of this hill

Myrddyn Phillips (February 2019)

Mapping Mountains – Trimble Surveys – Yr Eifl

03.10.18  Cae Doctor (SH 304 399)  

The summit of Cae Doctor (SH 304 399)

This hill was the last of seven visited during the day with each summit being Trimbled, and as a marginal P30 and its bwlch not LIDARed, the summit and bwlch needed Trimbling. 

The summit of this hill comprises two glazing fields that are separated by an old and high field boundary incorporating a stone wall, gorse hedge and fence.  If time permitted I wanted to take a data set from each side of this boundary, but as the high ground of each field was visually similar, one data set was deemed sufficient if also bwlch data were gathered.

Leaving the car we followed a track that soon brought us to the boundary hedge, and deciding to survey the eastern side Aled walked the periphery of the field boundary and stopped where he judged the natural summit of the hill to be situated, within a couple of metres this matched the grid coordinates produced by LIDAR.

I placed the Trimble on top of a fence post to give it elevation above its immediate surrounds and with the assistance of Aled measured the offset between its internal antenna and the ground below and once the 0.1m accuracy level was attained pressed ‘Log’ and we each then stood either side of the equipment and a few metres away from it.

Gathering data at the summit of Cae Doctor

During data collection two vehicles appeared on the hillside opposite, the higher one belonged to the local gamekeeper, whilst the lower vehicle was dropping feed off for livestock and turned out to be the local farmer, we found this out after the Trimble had gathered its allotted data and was packed away, as when we walked toward the gate giving access to our inward track we were met by the local farmer, who seeing us in the field had driven up the track to find out what two people were doing standing in her field for ten minutes or so about 50 metres apart.  It was time for an explanation.

The Trimble set-up position at the summit of Cae Doctor

The local farmer is Awen Roberts and she proved more than helpful as once the Trimble and its function and our interest in upland place-name research was explained she told us that the field where we had been standing is known as Cae Doctor, and the adjacent field on the other side of the boundary hedge is known as Cae Myllt, and she then gave permission for the other high field to be surveyed.

Having thanked Awen we walked in to the other high field, found its natural high point and again I positioned the Trimble on an adjacent fence post and waited for the allotted data to be gathered and stored.  All that remained was to visit and gather a data set from the bwlch.

Gathering data at the summit of Cae Myllt

The bwlch for this hill lies in a long valley that is steep sided with a public footpath leading us to where contour interpolation places its critical point.  Again the Trimble was placed on top of a fence post to give it elevation and the offset measured, and once the allotted data were gathered we walked back up to the awaiting car and I then drove the short distance to Nefyn. 

Heading toward the bwlch

The first data set in the area of the bwlch

The reason for doing so is that the Ordnance Survey Interactive Coverage Map hosted on the Geograph website gives a 37m spot height at a road junction that could be the position of this hill’s critical bwlch, although we had dismissed this from our on-site visit to the valley as ground beyond where the Trimble had gathered data seemed to descend toward this road junction.  However, being a completest I wanted this last data set as a comparison with the previous one.

The second data set in the area of the bwlch

Once this last data set was stored I joined Aled in the car and drove back to pick his car up.  Once home Aled analysed LIDAR and determined the height and position of this hill’s bwlch, and when coupled with the Trimble summit data the hill retains its P30 status and increases its known drop value, and these values are given below.

  

Survey Result:

Cae Doctor (significant name change)

Summit Height:  67.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 30425 39978 (Trimble GeoXH 6000)

Bwlch Height:  35.8m (LIDAR)

Bwlch Grid Reference:  SH 30747 40107 (LIDAR)

Drop:  31.2m (Trimble GeoXH 6000 summit and LIDAR bwlch) (30-99m Sub-Twmpau reclassified to 30-99m Twmpau)

Dominance:  46.59% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble Survey Spreadsheet