Mapping Mountains – Hill Reclassifications – 200m Twmpau

Pt. 218.8m (SO 122 978) – 200m Sub-Twmpau deletion

There has been a deletion to the list of 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill confirmed by LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

Pt. 218.8m (SO 122 978)

The criteria for the list that this deletion 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

The hill is being listed by the point (Pt. 218.8m) notation as an appropriate name for it either through local enquiry and / or historic research has not been found by the author, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is positioned with minor roads to its south-east and north, and has the B4389 road to its south-west, and has the small community of Betws Cedewain towards the south. 

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 accompanying Hills to be surveyed sub list, and listed with an estimated c 230m summit height. 

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 27m of drop, based on an estimated c 231m summit height and a 204m bwlch height, with the latter based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map.  An anomaly was also noted with the heights given the contours on the upper part of this hill on the 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 image of Pt. 218.8m

The result produced by LIDAR analysis gives this hill a 218.8m summit height and 13.6m of drop, confirming that the uppermost contour on the 1:25,000 Explorer map is not 230m, and as the summit has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes. 

The Trimble GeoXH 6000 gathering data at the summit of Pt. 218.8m

Therefore, the deletion of this hill from 200m Sub-Twmpau status is due to LIDAR analysis and a Trimble GeoXH 6000 survey, resulting in a 218.8m summit height and a 205.3m bwlch height, with these values giving this hill 13.5m of drop, which is insufficient for it to be classified as a 200m Sub-Twmpau. 

 

The full details for the hill are: 

Group:  Carnedd Wen 

Name:  Pt. 218.8m 

OS 1:50,000 map:  136

Summit Height:  218.8m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SO 12216 97806 (Trimble GeoXH 6000) 

Bwlch Height:  205.3m (LIDAR) 

Bwlch Grid Reference:  SO 12899 97950 (LIDAR) 

Drop:  13.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (January 2021)

 

 

 

 

 

 

  

Mapping Mountains – Trimble Surveys – Hafod Ithel

 

15.10.20  Hafod Ithel (SN 610 677, previously Trimbled) 

I’d waited many years to visit this hill, and sixteen days after doing so I was heading back to it driving on the same narrow lane leading up its western flank in the good company of Charles Everett.  And like me sixteen days ago; this would be the first visit to Hafod Ithel for Charles. 

When I visited this hill in late September the forecast for blue skies had been overtaken by grey cloud pushing northward from the Preseli hills to the south.  Today, those blue skies were now above and the hill was bathed in early afternoon sunshine. 

Locking the car I followed Charles and sauntered the short distance toward the memorial to the Four Poets; T Hughes Jones, B T Hopkins, E Prosser Rhys and J M Edwards.  This is positioned close to a slender rib of rock and sits proudly and unobtrusively amongst the landscape. 

At the memorial to the Four Poets

Leaving the memorial we walked back down the path leading past my car and continued up on to the moor on the good path leading direct to the trig pillar atop the high point of Hafod Ithel. 

Charles heading for the summit of Hafod Ithel

Below us Llyn Eiddwen glistened, glinting and playing in the light.  To our north-east the rusted autumnal colour led the eye to the wind turbines close to the summit of Hafod Llŷn.  It was good to be here again, even though it was only a short time since my first visit. 

Llyn Eiddwen

Approaching on the path from the south were two people and they soon joined us at the summit.  We chatted for a number of minutes and they told us they had come from Lampeter for the day and were on a five mile circular walk. 

Looking toward Hafood Llŷn

Before leaving the summit Charles and I discussed whether the high point of the hill comprises an ancient tumulus.  I have found no proof of this either from old Ordnance Survey maps or historic records, but the ground hereabouts does lend itself to some form of human interference as it looks to be artificially raised. 

Leaving the summit it was only a short walk back on the greened path to my car.  Hafod Ithel was the sixth hill of a planned nine during the day, and or next; Banc Uchaf (SN 617 743) was due north and involved more navigating by Charles to find our way through the myriad of narrow lanes that dot the landscape hereabouts. 

 

Survey Result: 

 

Hafod Ithel  

Summit Height:  360.4m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Summit Grid Reference:  SN 61062 67794 (from previous Trimble GeoXH 6000 survey)

Bwlch Height:  204.4m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Bwlch Grid Reference:  SN 64577 68898 (from previous Trimble GeoXH 6000 survey)

Drop:  156.0m (from previous Trimble GeoXH 6000 survey)

Dominance:  43.29% (from previous Trimble GeoXH 6000 survey) 

 

For details of the Trimble GeoXH 6000 survey of this hill 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales

Craig y Fron (SJ 289 570) – Sub-Trichant addition

There has been confirmation of an addition to the list of Y Trichant – The 300m Hills of Wales, 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 Craig y Fron (SJ 289 570)

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

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Craig y Fron, and it is adjoined to the Moel y Gamelin group of hills, which are situated in the north-eastern part of North Wales (Region A, Sub-Region A2), and it is encircled by minor roads with the A541 road to its north-east, the A5104 road to its north-west and the B5101 road to its south-west, and has the village of Caergwrle towards the east. 

When the original 300m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was not 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 this sub category. 

After the P30 lists were standardised, and interpolated heights and drop values also included, this hill was listed with an estimated c 22m of drop based on the 324m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated bwlch height of c 302m based on interpolation of contours between 300m – 305m that appear on the Ordnance Survey 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 confirmation of the addition of this hill to Sub-Trichant status is due to LIDAR analysis, resulting in a 324.0m summit height and a 300.1m bwlch height, with these values giving this hill 23.8m of drop, which is sufficient for it to be classified as a Sub-Trichant. 

 

The full details for the hill are: 

Group:  Moel y Gamelin 

Name:  Craig y Fron 

OS 1:50,000 map:  117

Summit Height:  324.0m (LIDAR)                                                           

Summit Grid Reference:  SJ 28971 57067 (LIDAR) 

Bwlch Height:  300.1m (LIDAR) 

Bwlch Grid Reference:  SJ 29269 57113 (LIDAR) 

Drop:  23.8m (LIDAR) 

 

Myrddyn Phillips (January 2021)

 

 

  

Mapping Mountains – Trimble Surveys – Elenydd

 

15.10.20  Banc (SN 598 714) 

LIDAR image of Banc (SN 598 714)

Finding appropriate parking when visiting smaller heighted hills can be problematic.  Many such hills are situated close to narrow lanes amongst farming communities.  The next hill on our continuing day’s adventure was a prime example as when I drove a Google car on my laptop prior to us visiting, the best place I could find was to leave the car on the lane close to where the road widened on a corner, this was not ideal.  However, when we arrived at this point there was just enough room to squeeze the car on to the track that leads to Penciog leaving just sufficient space for a vehicle to pass if required. 

By the time I gathered my rucksack and camera and locked the car, Charles had headed through a gate leading toward a small disused quarry.  I opted to walk up the track to where the continuation of the public footpath accesses a field through a gate, and a couple of minutes walking up beside a fence and there was Charles waiting for me. 

To our right the land was brambled with small trees and scrub undergrowth, continuing up beside the fence open grazing fields soon appeared, and a short time later via a couple of gates we were at the summit area of the hill. 

Charles approaching the summit of Banc

Prior to us visiting I had analysed this hill’s details via LIDAR and using the Trimble as a hand-held device the ten figure grid reference for its high point now led us toward its summit. 

Within a few minutes the Trimble was set-up on top of my rucksack and the offset between its internal antenna and ground at its base measured and noted, and once the 0.1m accuracy level was attained I pressed ‘Log’ and scampered away to leave it gather its allotted data. 

Gathering data at the summit of Banc

To our south-east the wind turbines close to the summit of Hafod Llŷn (SN 625 700) drew the eye, whilst further south the moorland summit of Hafod Ithel (SN 610 677) poked above the horizon. 

Like many other smaller heighted hill’s, this one was not necessarily memorable.  It is neither dramatic, nor could I in any sincerity recommend it to visit.  However, the 45 minutes we spent walking up it, gathering summit data and reversing our route down it, proved very enjoyable, and like many hills of similar height it gives quiet surrounds with good views. 

 

Survey Result:

 

Banc (significant name change)  

Summit Height:  204.4m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 59804 71470 (Trimble GeoXH 6000) 

Bwlch Height:  170.1m (LIDAR)

Bwlch Grid Reference:  SN 62289 71880 (LIDAR)

Drop:  34.4m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  16.82% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

 

Mapping Mountains – Summit Relocations – 200m Twmpau

 

Field Above The House (SO 135 990) 

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 and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

Field Above The House (SO 135 990)

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 category entitled the 200m Sub-Twmpau consisting of all Welsh hills at or above 200m and below 300m in height that have 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

The name the hill is now listed by is Field Above The House and this was derived from local enquiry, and it is adjoined to the Carnedd Wen group of hills which are situated in the south-eastern part of North Wales (Region A, Sub-Region A4), and it is encircled by minor roads, with also the B4390 road to its north, the B4389 road to its west and the A483 road to its south-east, and has the village of Tregynon towards the west. 

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, and listed with a 263m summit height, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

After the P30 lists were standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was subsequently noted that the interactive mapping on the Magic Maps and the WalkLakes websites give this hill a 265m summit spot height. 

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 Field Above The House

LIDAR analysis shows the ground at the base of a raised field boundary to be the highest on the hill, however as this is deemed a relatively recent man-made construct such ground is discounted from the height of a hill in the listings I author.  LIDAR analysis also shows the position of the natural summit of this hill and this has now been surveyed with the Trimble GeoXH 6000 and it is this result that is being prioritised for this hill. 

The Trimble GeoXH 6000 gathering data at the summit of Field Above The House

The summit height and position produced by the Trimble GeoXH 6000 survey is 264.9m at SO 13508 99039, and this position in relation to the raised field boundary shown by LIDAR analysis 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, to a different feature such as in a conifer plantation, placed within a different map contour, to a different point where a number of potential summit positions are within close proximity, or 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 that is judged to be 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 new listed summit height for this hill is 264.9m and is positioned at SO 13508 99039, this position is given a 263m spot height on contemporary Ordnance Survey 1:25,000 Explorer maps and is approximately nine metres from where LIDAR gives the high point of the raised field boundary. 

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Carnedd Wen

Name:  Field Above The House

OS 1:50,000 map:  136

Summit Height:  264.9m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference (New Position):  SO 13508 99039 (Trimble GeoXH 6000) 

Bwlch Height:  220.0m (LIDAR) 

Bwlch Grid Reference:  SO 13331 98643 (LIDAR) 

Drop:  44.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

Myrddyn Phillips (January 2021)

 

 

 

Mapping Mountains – Trimble Surveys – Elenydd

 

15.10.20  Banc Tan y Cwarel (SN 583 747) 

LIDAR image of Banc Tan y Cwarel (SN 583 747)

Hill walking is like most things in life; as preparation beforehand can save time when on the hill.  And when faced with writing blog posts and detailing name changes or summit relocations, analysis of LIDAR and scrutinising the Tithe map beforehand can give an accurate summit and bwlch location and an appropriate name for the hill. 

Whereas LIDAR helps with height and position the Tithe is proving extremely important for finding appropriate names for lower heighted hills that are not necessarily thought of as ‘hills’ in the local community, more as high fields. 

Therefore, having done the prep, Charles and I visited this hill and I had come prepared with detailed notes for its summit position and with the Tithe name of Banc Tan y Cwarel for the enclosed land that takes in the high point of the hill. 

The morning was proving glorious with blue skies and just a tinge of autumnal warmth.  I parked my car on a grass verge opposite a gate that gave access to a disused small quarry which is placed north-east of the hill’s summit.  The quarry had left a vertical face of slate or mud stone, which in the late morning light glistened in inviting hues of grey. 

The small disused quarry

Ground rose steeply on the left-hand side of the quarry and we followed this up to a fence which gave access to a field leading toward the high point of the hill.  Crossing the field a Red Kite glided overhead, looking up I could distinctly see its eyes looking down toward us.  These are majestic birds and a number had glided the skies surrounding us during the morning’s hill bagging.

Always a pleasure seeing Red Kite's flying overhead

The high point of the hill was beside a gate which had raised field boundaries running from it.  Under a section of the gate and beside one of these boundaries was a large rock.  We debated whether the summit of the hill was the top of the rock or ground near its base, as although the rock is obviously natural it was an oddity as no other rock could be seen on the area of the summit.  It could of course be an erratic, or it could for whatever reason have been brought here by a farmer.  We concluded that we could not prove this one way or the other, and as the rock could not be moved it was now a part of the hill and therefore should be the point to gather data from. 

Gathering data at the summit of Banc Tan y Cwarel

As the Trimble quietly beeped away gathering its allotted data I sat with Charles on the lower part of one of the adjacent raised field boundaries and enjoyed the sunshine and the peaceful surrounds. 

Once the Trimble had gathered and stored data, I closed it down and before leaving the summit looked out toward our previous hill of the morning; Banc (SN 568 757) with its high mast dominating the westward view.  Between us and it were a myriad of grazing fields with the customary small white dots of sheep and the small community of Blaen-plwyf winding its way up beside a narrow lane. 

If visiting all nine hills on our planned route for the day, it would take us on a sweep southward of Aberystwyth edging our way eastward as we did so.  Banc Tan y Cwarel was our fourth hill of the morning, all had been done at a leisurely pace and now turning away from the summit we retraced our steps back toward the quarry and the awaiting car.  Our next hill, with its upper field also named on the Tithe as Banc (SN 598 714); was positioned about 3.5km south south-eastward from where we now were.  The day was progressing well and proving very enjoyable.

 

Survey Result: 

 

Banc Tan y Cwarel (significant name change)  

Summit Height:  182.9m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 58349 74798 (Trimble GeoXH 6000) 

Bwlch Height:  142.3m (LIDAR)

Bwlch Grid Reference:  SN 57897 75028 (LIDAR)

Drop:  40.6m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  2.18% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet