Mapping Mountains – Trimble Surveys – Mynydd Epynt

30.12.18  Cefn Merthyr Cynog (SN 976 383), Cefn Trum yr Hwch (SN 991 401), Cefn Bach (SO 004 387), Cefn Bach (SO 002 372, previously Trimbled), Gaer Fach (SO 009 366, previously Trimbled) and Corun Fanolau (SO 015 361, previously Trimbled) 

Misted grey drizzled December days can have their compensation when on the hill, as there is a beauty to walking in the mist with its delicate and quiet movement.  Today was one such day.

Setting off from the damp surrounds of Merthyr Cynog two farm dogs quickly scampered ahead and would remain with us until the summit of our first hill of the day; Cefn Merthyr Cynog.  As we made steady progress up a muddied track the hill lay ahead with its upper part obscured by a greyness that enclosed the surrounding land.

The two dogs were from the local farm and spent much of their time rounding up sheep, whilst we zeroed in to the summit of this first hill with the aid of the ten figure grid reference produced by LIDAR analysis conducted by one of my two companions on the walk. 

As the Trimble gathered its first data set of the day a wind battered red flag flapped on the opposing side of a barb wired fence, near to it was a sign proclaiming this to be a military firing range, but between Christmas and New Year these hills are free of gunfire which gives an opportunity to visit hills that otherwise are out of bounds for the remainder of the year.

Gathering data at the summit of Cefn Merthyr Cynog

Beyond the red flag a small conifer plantation, rectangle in shape, stood steadfast on the hillside, these are one of the landmarks of present day Epynt and can be seen from many miles away.

As we continued beyond the summit on the open hill a farm vehicle sped past on the near road, disappearing in to its blanket of grey.  It was this road we then joined and it took us down to the Ysgir Fawr, which gently flowed down to the lower southern lands past the boundary fence with its adjacent red flag.  It seems nature has few boundaries whilst that of man is an utter contrast.

The route down toward the Ysgir Fawr

The Ysgir Fawr

The paved road continued beyond the stream, with our route now taking us uphill.  The road seemed pristine with its wide tarmac cut through and laid upon the open hill side, it led us back into the mist toward the summit of our second hill of the day; Cefn Trum yr Hwch.

The paved road leading toward the summit of Cefn Trum yr Hwch

Just before the summit a farm vehicle appeared coming up the road and swinging right toward the high point of the hill, I waved toward it and it stopped and as I approached I smiled and said ‘hello Austin’, it was Austin Davies who I had visited many years ago making place-name enquires for the Epynt, Austin had given me many names of hills and features that have never appeared on any Ordnance Survey map and as we chatted my two colleagues joined us, one had a map with the names Austin had given transposed on it, and he spent many minutes going through these names with Austin, checking their position and listening to their pronunciation.

Waving Austin off we continued to the summit where the second Trimble data set of the day was gathered.  It was now downhill toward a minor road where a few metres in to a rough grassed bog lay the critical bwlch of Corun Fanolau, whose summit I had surveyed three years ago.

Gathering data at the summit of Cefn Trum yr Hwch

Gathering data at the critical bwlch of Corun Fanolau

As the Trimble gathered its data, drizzle pushed across the hills from the west, the pattern of weather with the ebb and flow of mist and gentle drizzle was now set for the day, and although not constant it brought dampened conditions and a chilled feeling if stationary for any length of time.

Ahead lay the Cefn Bach ridge which consists of two 391m map heighted summits, the southern of which was Trimbled three years ago, and it was now the turn of the northerly summit.  Gates led across the grazing fields, all manicured green and yet dulled by the afternoon’s monochrome stillness.

Gathering data at the northerly of the two Cefn Bach summits

Just two hills remained; Gaer Fach and Corun Fanolau, both had previously been surveyed and therefore I packed the Trimble away in my rucksack.  Both are fine hills, the first with the remains of an ancient Iron Age hillfort and the second with a series of small crags below its high point.

It felt refreshing not to have to Trimble these summits, a freedom of sort, and beyond was welcome downhill past the old farm house of Fanolau to a steep track leading to the minor road where a car was waiting.

       

Survey Result:

Cefn Merthyr Cynog

Summit Height:  408.5m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 97601 38378 (Trimble GeoXH 6000)

Bwlch Height:  376.1m (LIDAR)

Bwlch Grid Reference:  SN 96738 39406 (LIDAR)

Drop:  32.4m (Trimble GeoCH 6000 summit and LIDAR bwlch)

Dominance:  7.93% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Cefn Trum yr Hwch

Summit Height:  432.5m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 99171 40169 (Trimble GeoXH 6000)

Bwlch Height:  394.6m (LIDAR)

Bwlch Grid Reference:  SN 98341 43330 (LIDAR)

Drop:  37.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  8.76% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Cefn Bach

Summit Height:  389.4m (converted to OSGM15) (Trimble GeoXH 6000) (390m Sub-Pedwar deletion) (twin summit status with Cefn Bach positioned at SO 00293 37291 confirmed with 389.391m and 389.392m respectively, with 1mm difference the Trimble is unable to split these tops)

Summit Grid Reference:  SO 00470 38742 (Trimble GeoXH 6000)

Bwlch Height:  368.9m (LIDAR)

Bwlch Grid Reference:  SO 00075 38322 (LIDAR)

Drop:  20.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) (non-prioritised drop for listing purposes)

Dominance:  5.26% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Cefn Bach

Summit Height:  389.4m (converted to OSGM15, previously Trimbled) (390m Sub-Pedwar deletion confirmed) (twin summit status with Cefn Bach positioned at SO 00470 38742 confirmed with 389.392m and 389.391m respectively, with 1mm difference the Trimble is unable to split these tops)

Summit Grid Reference:  SO 00293 37291

Bwlch Height:  335.0m (converted to OSGM15, previously Trimbled)

Bwlch Grid Reference:  SO 00287 36949

Drop:  54.4m (prioritised drop for listing purposes)

Dominance:  13.98%

Gaer Fach (significant name change)

Summit Height:  413.3m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)

Summit Grid Reference:  SO 00915 36622

Bwlch Height:  377.4m (LIDAR)

Bwlch Grid Reference:  SO 01225 36448 (LIDAR)

Drop:  35.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  8.68% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Corun Fanolau (significant name change)

Summit Height:  423.2m (converted to OSGM15, previously Trimbled)

Summit Grid Reference:  SO 01525 36160

Bwlch Height:  326.7m (converted to OSGM15)

Bwlch Grid Reference:  SN 99991 39512

Drop:  96.5m

Dominance:  22.81%

For details on the survey of Gaer Fach, Corun Fanolau and Cefn Bach

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains – Hill Reclassifications – Y Pedwarau - The 400m Hills of Wales

The two tops of Cefn Bach have now been surveyed with the Trimble GeoXH 6000, resulting in:

Surveyed on 18.08.15: 389.392m at SO 00293 37291

Surveyed on 30.12.18:  389.391m at SO 00470 38742

With 1mm difference in height the Trimble is unable to split these summits, therefore they remain deleted from 390m Double Sub-Pedwar status and are reinstated as twin Trichant tops, the post below remains as originally written for historic merit.



Cefn Bach (SO 004 387) - 390m Double Sub-Pedwar deletion

There has been a deletion of a 390m Double Sub-Pedwar by analysis of LIDAR data by Aled Williams.  The 390m Double Sub-Pedwarau is one of three categories of sub hills that accompany the main Y Pedwarau list, with the criteria for 390m Double Sub-Pedwar status being all Welsh hills at or above 390m and below 400m in height with 20m or more and below 30m of drop.

The hill is situated in the group of hills known as Mynydd Epynt with its Cardinal Hill being Mynydd Epynt (SN 961 464) and is placed in the Region of Mid and West Wales (B-2).  The hill is positioned between the small communities of Upper Chapel to the north, Lower Chapel to the south-east and Merthyr Cynog to the south-west, and between the river valleys of the Ysgir Fawr to the west and the Honddu to the east.  A narrow lane passes to the north of this hill and a public footpath leads from this to just below the summit.

The name of the hill is Cefn Bach and it had been listed in the Y Pedwarau Europeaklist booklet with c 22m of drop based on its 391m summit spot height at SO 00375 38722 and an estimated bwlch height of c 369m based on bwlch contouring between 360m – 370m.  This hill was listed as a 390m Double Sub-Pedwar in deference to its 391m map heighted twin summit which was listed as the 390m Sub-Pedwar with its 391m spot height at SO 00284 37297, these two hills are aligned in a north – south direction, with the southerly hill being listed with 55m of drop based on a 336m bwlch spot height.

Since the Europeaklist publication of the Y Pedwarau the southerly of these two 391m map heighted hills has been surveyed with the Trimble GeoXH 6000 resulting in a 389.4m (converted to OSGM15) summit height at SO 00293 37291 and a 335.0m (converted to OSGM15) bwlch height at SO 00287 36949.  However, the northerly summit remained un-Trimbled and the relative height of each summit was only ascertained from analysis of LIDAR data.

As Aled was analysing other hills in the vicinity against LIDAR data, he did likewise with the two Cefn Bach hills.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data gives the hill the following details:

Cefn Bach

Summit Height:  389.2m

Summit Grid Reference:  SO 00471 38745

Bwlch Height:  368.9m

Bwlch Grid Reference:  SO 00075 38322

Drop:  20.3m

Therefore, the 389.2m LIDAR data produced for the summit position at SO 00471 38745 and the 368.9m LIDAR data produced for the bwlch position at SO 00075 38322 is insufficient for this hill to retain its 390m Double Sub-Pedwar status as its summit is below the required height threshold.

The full details for the hill are:

Cardinal Hill:  Mynydd Epynt

Summit Height:  389.2m (LIDAR data)

Name:  Cefn Bach

OS 1:50,000 map:  160

Summit Grid Reference:  SO 00471 38745

Drop:  20.3m (LIDAR data)

This now brings the overall total for the 390m Double Sub-Pedwarau to 27 hills with 13 additions and two deletions to this sub category of hill since publication of the list by Europeaklist in May 2013.  The hill will be taken out of the 390m Double Sub-Pedwar list in forthcoming publications of the Y Pedwarau.  The list of Pedwar hills is available from the Haroldstreet website (January 2014) with all subsequent changes available via the Mapping Mountains site.

The additions, reclassifications and deletions to the 390m Double Sub-Pedwarau since the 1^st edition of the Y Pedwarau was published by Europeaklist are as follows:

390m DOUBLE SUB-PEDWAR ADDITIONS

Boncyn Nadroedd (SJ 027 540) c 390m summit and c 23m drop

Derwydd Bach (SO 017 503) 399m summit and c 27m drop

Ffridd Felen (SH 855 388) 392m summit and c 21m drop

Cefn Uchaf (SJ 249 402) c 395m summit and c 21m drop

Carreg y Frân (SH 961 140) 396m summit and 20m drop

Ffridd Dyfnant (SH 997 164) 399m summit and 21m drop

Pt. 393m (SH 796 120) 393m summit and 24m drop

Craig Cefn Llech (SN 952 771) 398m summit and 23m drop

Pt. 394m, The Begwns (SO 144 445) 394m summit and c 20m drop

Pt. 393m (SN 998 432) 393m summit and c 20m drop

Pt. 399m (SO 027 385) 399m summit and c 21m drop

Craig Rhiw Berfa (SS 945 906) 399m summit and c 21m drop(later deleted)

Penmaen Mawr (SH 698 755) 390.4m summit and 26.9m drop

  

390m DOUBLE SUB-PEDWAR DELETIONS

Craig Rhiw Berfa (SS 945 906) 397.2m summit and 18.8m drop

Cefn Bach (SO 004 387) 389.2m summit and 20.3m drop

Cefn Bach (SO 004 387) the deleted 390m Double Sub-Pedwar

Myrddyn Phillips and Aled Williams (January 2017)

Mapping Mountains – Hill Reclassifications – Y Pedwarau - The 400m Hills of Wales

The two tops of Cefn Bach have now been surveyed with the Trimble GeoXH 6000, resulting in:

Surveyed on 18.08.15: 389.392m at SO 00293 37291

Surveyed on 30.12.18:  389.391m at SO 00470 38742

With 1mm difference in height the Trimble is unable to split these summits, therefore they remain deleted from 390m Sub-Pedwar status and are reinstated as twin Trichant tops, the post below remains as originally written for historic merit.

Cefn Bach (SO 002 372) - 390m Sub-Pedwar deletion

There has been a deletion of a 390m Sub-Pedwar by analysis of LIDAR data by Aled Williams.  The 390m Sub-Pedwarau is one of three categories of sub hills that accompany the main Y Pedwarau list, with the criteria for 390m Sub-Pedwar status being all Welsh hills at or above 390m and below 400m in height with a minimum 30m of drop.

The hill is situated in the group of hills known as Mynydd Epynt with its Cardinal Hill being Mynydd Epynt (SN 961 464) and is placed in the Region of Mid and West Wales (B-2).  The hill is positioned between the small communities of Lower Chapel to the east south-east and Merthyr Cynog to the west, and between the river valleys of the Ysgir Fawr to the west and the Honddu to the east.  A narrow lane passes just to the south of this hill’s summit and one car can be parked beside it at its high point, this affords easy access toward the summit on a public footpath.

The name of the hill is Cefn Bach and it had been listed in the Y Pedwarau Europeaklist booklet with 55m of drop based on its 391m summit spot height at SO 00284 37297 and the 336m bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer map.  This hill was prioritised as a 390m Sub-Pedwar in preference to its 391m map heighted twin summit which was listed as the 390m Double Sub-Pedwar with its 391m spot height at SO 00375 38722, these two hills are aligned in a north – south direction, with the northerly hill being listed with c 22m of drop based on an estimated bwlch height between the two hills of c 369m.

Since the Europeaklist publication of the Y Pedwarau the southerly of these two 391m map heighted hills has been surveyed with the Trimble GeoXH 6000 resulting in a 389.4m (converted to OSGM15) summit height at SO 00293 37291 and a 335.0m (converted to OSGM15) bwlch height at SO 00287 36949.

As Aled was analysing other hills in the vicinity against LIDAR data, he did likewise with the two Cefn Bach hills.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data gives the hill the following details:

Cefn Bach

Summit Height:  389.4m

Summit Grid Reference:  SO 00293 37291

Bwlch Height:  335.0m

Bwlch Grid Reference:  SO 00293 36953

Drop:  54.4m

Therefore, the 389.4m LIDAR data produced for the summit position at SO 00293 37291 and the 335.0m LIDAR data produced for the bwlch position at SO 00293 36953 when coupled with the LIDAR data confirming that the northerly Cefn Bach summit at SO 00471 38745 is 389.2m high and therefore lower than its southerly adjacent hill, is sufficient for this hill to be deleted from the ranks of 390m Sub-Pedwarau as its summit is below the height threshold.

The full details for the hill are:

Cardinal Hill:  Mynydd Epynt

Summit Height:  389.4m (converted to OSGM15) (Trimble and LIDAR data)

Name:  Cefn Bach

OS 1:50,000 map:  160

Summit Grid Reference:  SO 00293 37291

Drop:  54.4m (Trimble and LIDAR data)

This now brings the overall total for the 390m Sub-Pedwarau to 37 hills with two deletions to this sub category of hill since publication of the list by Europeaklist in May 2013.  The hill will be taken out of the 390m Sub-Pedwar list in forthcoming publications of the Y Pedwarau.  The list of Pedwar hills is available from the Haroldstreet website (January 2014) with all subsequent changes available via the Mapping Mountains site.

The additions, reclassifications and deletions to the 390m Sub-Pedwarau since the 1^st edition of the Y Pedwarau was published by Europeaklist are as follows:

390m SUB-PEDWAR DELETIONS

Moel Fodiar (SH 978 680) deleted as 389.8m summit too low

Cefn Bach (SO 002 372) (Trimble and LIDAR data) deleted as 389.4m summit too low

Cefn Bach (SO 002 372) the deleted 390m Sub-Pedwar

Myrddyn Phillips and Aled Williams (January 2017)

Mapping Mountains – Hill Reclassifications – Y Pedwarau - The 400m Hills of Wales

Cefn Bach (SO 208 038) - 400m Sub-Pedwar addition

There has been a new 400m Sub-Pedwar added to the list by analysis of LIDAR data by Aled Williams.  The 400m Sub-Pedwarau are the Welsh hills at or above 400m and below 500m in height with a drop between 20m and below 30m.

The hill is situated in the group of hills known as the Y Cymoedd with its Cardinal Hill being Mynydd Carn y Cefn (SO 187 085) and is placed in the Region of South Wales (C-2).  The hill is positioned above the town of Abertyleri (Abertillery) to its east and between the river valleys of the Afon Ebwy (Ebbw River) to the west and the Afon Ebwy Fach (Ebbw Fach River) to the east, and can be easily accessed from a track from its south, and from the continuation of the track from the west.

The name of the hill is Cefn Bach and prior to the analysis of LIDAR data the hill was catalogued as having only 7m of drop based on a 416m summit spot height at SO 20738 04263 and a 409m bwlch spot height at SO 20369 04523, with the latter spot height appearing on the Ordnance Survey enlarged mapping on the Geograph website.  The contouring near the area of the bwlch is different between the Ordnance Survey 1:25,000 Explorer map and the enlarged Geograph map and the summit position indicated by LIDAR is on the edge of the uppermost contour on current 1:25,000 maps, with the contouring disappearing at this same position on the enlarged Geograph map, indicating that the present day summit is the relic of mine spoil, this is confirmed when analysing older maps.

As Aled was analysing other hills in the vicinity against LIDAR data, he did likewise with Cefn Bach.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data gives the hill the following details:

Cefn Bach

Summit Height:  427.2m

Summit Grid Reference:  SO 20819 03887

Bwlch Height:  406.2m

Bwlch Grid Reference:  SO 20893 03917

Drop:  21.0m

Therefore, the 427.2m LIDAR data produced for the summit position at SO 20819 03887 and the 406.2m LIDAR data produced for the bwlch position at SO 20893 03917 is sufficient for this hill to be reclassified to a 400m Sub-Pedwar with 21.0m of drop, and therefore Cefn Bach is included in the listing of 400m Sub-Pedwar hills and the list of Y Pedwarau will be updated accordingly.  The list of Pedwar hills is available from the Haroldstreet website (January 2014) with all subsequent changes available via the Mapping Mountains site.

The full details for the hill are:

Cardinal Hill:  Mynydd Carn y Cefn

Summit Height:  427.2m (LIDAR data)

Name:  Cefn Bach

OS 1:50,000 map:  171

Summit Grid Reference:  SO 20819 03887

Drop:  21.0m (LIDAR data)

The list of additions, reclassifications and deletions from the 400m Sub-Pedwar list since the 1^st edition of the Y Pedwarau was published by Europeaklist are as follows:

400m SUB-PEDWAR ADDITIONS

Pt. 452.4m (converted to OSGM15) (SJ 229 443) 22.6m drop

Bryn Glas (SH 735 420) 21.7m drop

Derlwyn (SH 588 586) 20.4m drop

Moel Tryfan (LIDAR data) (SH 517 559) 21.5m drop

Cefn Bach (LIDAR data) (SO 208 038) 21.0m drop

Pt. 422.3m (converted to OSGM15) (SO 073 822) Pedwar reclassified to 400m Sub-Pedwar with 29.0m drop

Wenallt (SN 933 571) Pedwar reclassified to 400m Sub-Pedwar with 28.3m drop

Bryn Serth (SO 147 109) Pedwar reclassified to 400m Sub-Pedwar with 25.4m drop

Banc Bronderwgoed (SN 871 987) Pedwar reclassified to 400m Sub-Pedwar with 27.7m drop

Drysgol (SN 946 744) Pedwar reclassified to 400m Sub-Pedwar with 29.2m drop

Craig y Garreg-lwyd (SH 730 427) Pedwar reclassified to 400m Sub-Pedwar with 29.9m drop

Pt. 407.7m (converted to OSGM15) (SO 180 692) Pedwar reclassified to 400m Sub-Pedwar with 28.3m drop

Twyn Disgwylfa (LIDAR data) (SS 995 959) Pedwar reclassified to 400m Sub-Pedwar with 28.8m drop

400m SUB-PEDWAR RECLASSIFICATIONS

Y Garn (SH 758 375) 400m Sub-Pedwar reclassified to Pedwar with 31.2m drop

Cefn Perfa (SO 173 579) 400m Sub-Pedwar reclassified to Pedwar with 30.1m drop

Craig y Ganllwyd (SH 707 258) 400m Sub-Pedwar reclassified to Pedwar with 33.4m drop

Pt. 499.5m (converted to OSGM15) (SH 665 310) 400m Sub-Pedwar reclassified to Pedwar with 30.3m drop

Mynydd Poeth (SH 953 513) 400m Sub-Pedwar reclassified to Pedwar with 31.7m drop

Pt. 415.6m (LIDAR data) (SO 243 011) 400m Sub-Pedwar reclassified to Pedwar with 31.4m drop

400m SUB-PEDWAR DELETIONS

Moelfre (SO 121 759) 19.8m drop

Carreg y Big (SN 902 909) 19.7m drop

Foelas Fechan (SH 854 596) 18.6m drop

Moelfre (bwlch LIDAR data) (SH 717 744) 18.3m drop

Myrddyn Phillips and Aled Williams (December 2016)