Hill Lists – Cymru / Wales – 200m Twmpau updates – Pen Llŷn

The first list to the Welsh 200m P30 hills was published on Geoff Crowder’s website v-g.me in 2000; this list preceded the list of TuMPs by nine years, the list proved a very useful resource for the TuMP compilation for this category of hill.

The Welsh 200m P30 list documents all hills in Wales that are at or above 200m in height and are below 300m in height, to qualify for the main list each hill requires a minimum of 30m of prominence.

The hills listed below are updates to the Welsh 200m P30 list originally published on Geoff Crowder's website.  To see the original list click {here}

The original published list had a Sub-List which was entitled ‘Hills to Survey’.  This list consisted of all hills in Wales in the stipulated height band that have a minimum of 20m of prominence, but do not meet the minimum 30m of prominence to enter the main list, according to Ordnance Survey map spot heights and contours.  Nowadays the standard Sub-List takes in all hills that have a minimum of 20m of prominence.  However, the Hills to Survey Sub-List discounted hills whose map spot heights gave a drop value of less than 30m, but more than 20m.  By doing so, the only hills that were Sub-Listed were those that map values dictated stood a chance of entering the main list, for example; if a hill had a summit spot height of 250m and a bwlch spot height of 221m, it was not listed in the Hills to Survey Sub-List as with 29m of drop I thought it did not stand a chance of main list qualification. 

When compiling the Sub-List I was measuring many hills for P30 status using a basic levelling technique, please click {here} for more information concerning this.  I now know that Ordnance Survey spot heights have a standard margin of uncertainty of + / - 3m associated with their accuracy.  Therefore many hills that were not listed in the original Sub-List may have sufficient drop to enter the main list.  Because of this the Sub-List has been altered to include all hills that have a minimum of 20m of drop but are not known to attain the minimum 30m of drop to enter the main list.

The hills listed below are those major amendments to the original Welsh 200m P30 list as it appears on Geoff’s website.  There are many hills that have been promoted from the Hills to Survey Sub-List to the main list, whilst there are many additions to the Sub-List now that it has been standardised to include all 20m minimum but below 30m drop hills.

When the 200m P30 list was first published it was the first to this category of hills and in some way it and its other 100m height band lists paved the way for Clem’s data that later appeared on the RHB file database and then for the TuMPs listing by Mark Jackson.

As well as the first P30 list to this height band the list is now the first to include a comprehensive Sub-List.

TuMP baggers beware; as the main list also includes P30’s not listed by Mark Jackson, so if you want to visit all P30’s you’ll have to include some non TuMPs to do so.

The list will be updated on a weekly basis and will be done so through each Group category, starting from the north and working south.  The third Group that has major updates is Pen Llŷn.

Pen Llŷn

West of the Afon Dwyfor and the Afon Dwyfach from SH 478 372 to SH 453 485 and continuing to the Afon Desach and Aberdesach at SH 425 514.  Bordering with Moel Hebog to the east.

Twmpau - 200m updates

Moel Caerau    207m    SH 292 354

This hill was always a prime candidate for promotion from the sub-list and with the large scale Ordnance Survey mapping on the Geograph website giving a 173m spot height on the area of the bwlch it gives this hill 34m of drop.

Next update due on the 5^th May 2014

Mapping Mountains – Trimble Surveys – Foel Cedig

21.04.14  Gallt y Goedhwch (SJ 137 159) and Lower Field (SJ 137 155)

Gallt y Goedhwch (SJ 137 159)

Mark suggested meeting up and had originally thought of heading for Rhobell Fawr (SH 786 256), this was quickly shelved as the forecast predicted intense thunderstorms in mid Wales for the afternoon.  The next idea was a circuit in the Howgills, but it seemed the worsening weather was going to hit that part of England as well.  However, the forecast for the morning was set fair so he suggested upping his HuMP total and visiting Gallt y Goedhwch which is situated in the tranquil lands above the Dyffryn Meifod, a few miles from Welshpool.

The hill also had the added advantage of having two similar heighted tops for its main summit which has a 325m spot height on the Ordnance Survey enlarged Geograph map, and just to the south is another summit which has a small uppermost c 320m ring contour.  This has caused a bit of debate in the past between Douglas Law, Chris Watson, George Gradwell and me.  Hopefully the Trimble could distinguish which of the two similar heighted tops is the higher, give a height to the southerly summit, confirm this to be lower than the main summit and if we surveyed the bwlch between we could also give a drop value for the southern summit.  I also hadn’t visited this hill, so it would be a new P30 tick for me.

I had suggested starting from a relatively high road and approaching the hill from the south-east, but Mark pointed out that this route had a reputation for meetings with an inquisitive farmer, so we parked at a road junction where sufficient space for at least one car can be found at SJ 139 169.  This route would also enable us to have a good walk, instead of a quick bag.

As Mark was getting his boots on I sauntered over to the near hedge row and admired the colourful crop of wild flowers, all newly sprung with that luxuriant colour of early spring, highlighted by morning sunshine.  As we started eastward down the lane toward the farm of Gwaelod (SJ 142 164) we soon encountered all manner of friendly animals from donkeys to dogs; all wanted a pat and a lot of fuss.  From this vantage point Gallt y Goedhwch rose steeply above the green fields with its lower slopes covered in deciduous woodland, it was these slopes that we hoped to gain access on through to the summit.

We left the lane before the farm and joined a public footpath across a field which aimed for the lower reaches of the wooded slopes and a track that contoured its way around the hill.  Once in the wood we had to pick our spot when to bear left and head uphill.  Once picked, we wondered if an easier route may have existed further up the track, as our route was unforgivingly steep.  It was all rather beautiful though, as the land was covered in fallen foliage interspersed amongst mature trees, all quiet except for our labours and the welcome addition of bird song.

Crossing the field before entering the wood

The steep slopes in the wood

As height was gained we encountered a high fence, no doubt put in place for pheasant rearing.  A few minutes later and the steep slope started to relent as we came out of the wood to the northerly ridge of the hill.  Such a wonderful place to be on a morning bathed in blue sky, but we knew this was not going to last as the heat of the day was predicted to set off intense thunder showers in the early afternoon.

Emerging out of the wood on to the upper slopes of Gallt y Goedhwch

We were soon on the high point, or the two high points, we assessed the height difference between each and thought the more south-westerly one to be the higher, Mark thought by as much as 0.5m.  The Trimble was placed on each in turn, gathering ten minutes of data from both.  Each high point is easily identifiable as the summit consists of a small rocky ridge with the ground conveniently reaching its respective high points without bothersome intermediate rocky bits vying for possible other high points, outside of the two that we were now surveying and of course the other southerly summit that could be as high!!

The highest part of Gallt y Goedhwch is the south-westerly point of the main summit

Mark enjoys the rest whilst the Trimble gathers data at the north-easterly point of the main summit with the high point of the hill in the background

Once the data was stored we made our way to the bwlch between the main summit and the southerly one and had a good look at the ground, once the position of the critical bwlch was decided upon the Trimble was placed on the spot and gathered five minutes of data.

Gathering data at the bwlch between the two hills

The southerly summit is quite steep when approaching from its northerly bwlch.  The name of Maes y Castell appears on the map near to the summit of this hill but the Ordnance Survey 1:2,500 map from 1975 implies that this name is that of the farm at SJ 137 154, whilst the name of Y Bwythyn appears on the OS enlarged Geograph map, this name seems to be applicable to a cottage, whilst the Tithe map gives the name of Lower Field for land where the summit is situated and therefore it is this latter name that is now being used for that of the hill.  This southerly summit also consists of a small rocky ridge, within a few minutes the Trimble was balanced on top, aligned with its highest point.  Thankfully there was only a slight whisper of breeze that helped negate the heat of the sun, otherwise strong wind would no doubt have dislodged the Trimble and rolled it down the hillside.  Another ten minutes of data was collected as we lounged around in the sun and admired the view.

The Trimble GeoXH 6000 on the summit of  Lower Field

We headed westward from the bwlch and re-joined our inward track in the wood as the blue of the sky was replaced by an ominous murkiness; heralding what we thought was the impending storm.  Thankfully this never materialised for this part of Wales as the predicted intense rain concentrated itself to the south of the country. 

Four data points gathered and hopefully a few questions answered by the results, an excellent small walk taking just over three hours.

An Easter bunny, unfortunately a dead one.  We came across this during our descent back through the wood

Survey Result:

Gallt y Goedhwch

Summit Height:  325.7m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 13709 15922 (Trimble GeoXH 6000)

Bwlch Height:  212.1m (LIDAR)

Bwlch Grid Reference:  SJ 11170 14801 (LIDAR)

Drop:  113.6m (Trimble GeoXH 6000 summit and LIDAR bwlch) (Sub-Trichant reclassified to Trichant)

Dominance:  34.89% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Lower Field (significant name change)

Summit Height:  321.1m (converted to OSGM15)

Summit Grid Reference:  SJ 13704 15586

Bwlch Height:  295.3m (converted to OSGM15)

Bwlch Grid Reference:  SJ 13681 15650

Drop:  25.8m (Trichant reclassified to Sub-Trichant)

Dominance:  8.03%

For further details please consult the Trimble survey spreadsheet click {here}

Mapping Mountains – Trimble Surveys – Pumlumon

20.04.14  Cefn Penarth (SN 924 853)

Cefn Penarth (SN 924 853), bwlch on right near to farm and the summit on the left

I’d spent some time the previous evening trying to find two or three hills of interest whose P30 status needed checking or whose Sub status stood a chance of being promoted to a P30.  One that met the latter description was a hill on a descending easterly ridge to the south of Llyn Clywedog.  To make things easier the ridge that the hill is situated on has a minor road following its crest.  However, there are farms either side of the bwlch and summit and it looked like prime sheep grazing land, and as it is now just past lambing time, these little beasts may be with their mothers on the fields I wanted to survey, so I had to show caution and respect toward the beasties.

The road from my last hill (Pt. 381.7m SN 926 875) heads south-eastward toward Llanidloes, after a mile I turned right and then a few minutes later I turned left on to a steep and seldom used road with unenclosed fields on my right, lambs scampering about and three gates to open.  I tried my utmost to encourage the lambs to stay in their given fields when opening these gates, but I’m afraid one escaped in to a neighbouring field, so no doubt she is now wandering around trying to discover a new mother.

I parked beside the track entrance that leads down to the Upper Cefn-penarth farm (SN 920 855).  I’d looked at this road on the digitised Google Map the previous evening and noted ground ground immediately to the north of the road where a 288m spot height appears on Ordnance Survey maps was higher.  I’d also zoomed up the lane toward the summit where a 317m spot height appears on the OS map.  The high point of the hill was above this road.  Could the height difference between the land at the bwlch and summit be sufficient for P30 status to be confirmed?

The 288m spot height appears on this lane, the critical bwlch is higher and in the field on the right

Once out of the car I walked westward up the road to acclimatise myself with the lay of the land at the bwlch, the ground immediately north of the lane proved higher, I looked around for any farm vehicles on adjacent fields and sneaked over the fence, saying good morning to two small lambs and their mother as I did so.  No sooner was I in the field and one of these lambs walked toward me and nuzzled my leg, I ignored its advances!

I needed to be quick as I was in full view of the lane and the Upper Cefn-penarth farm was only over the lip of the field, I spent a few minutes on my knees judging the lay of land, picked my spot and set the Trimble to gather data.  Once the Trimble had been activated I headed to the nearby hedge and sat in the field below it and next to a particularly dense covering of hedgey stuff.  Within a couple of minutes the rumbles of a vehicle from the farm came up the lane, oh gawd, imagine trying to explain what I was doing.  I waited for it to pass and then hoped it wouldn’t turn right, as if it did I would be in full view of the occupant as they passed the fence I had clambered over.  Thankfully they turned left and headed up the lane toward the summit of the hill.  Once five minutes of data were collected I quickly packed the equipment away and walked up the lane to a gate just over the crest of the hill, which gave access to the summit field.

The Trimble GeoXH 6000 set-up position at the bwlch of Cefn Penarth with the Llyn Clywedog dam in the background

Looking up the lane toward the summit

I gathered three data sets from the summit area of the hill, one from what I judged to be the high point, one from the high point near to the road and the third from the high point of an earthen embankment that ran parallel to the road.  In all fifteen minutes of data were collected from these points and the same amount of time was probably spent setting the equipment up, during which I wandered around in a field, next to a road, hoping that no farmer’s vehicle would pass me.  The only one I could see was a quad bike on a lower field; I tried to keep out of his line of sight.

The Trimble GeoXH 6000 gathering data at the second point on the summit area, the high point of the hill is to the left

By 10.55am I was back at the car and travelling toward Llanidloes and then Welshpool.  Soon after arriving home the predicted rain arrived.  A great morning, only done because I’d mistakenly visited the lower top of Dinas two days previously, so I had to re-visit to get another data set. 

LIDAR image of Cefn Penarth

POSTSCRIPT:

Since this hill was Trimbled, LIDAR has become available and summit analysis undertaken by Joe Nuttall and sent to DoBIH prompted me to compare the Trimble result to that ascertained from LIDAR.  The Trimble result is 0.07m lower for the summit compared to LIDAR, but with an approximate 16 metre difference in summit position and a 7 metre difference in bwlch position, the LIDAR result is being prioritised.  

Survey Result:

Cefn Penarth (significant name change)

Summit Height:  318.9m (LIDAR)

Summit Grid Reference:  SN 92415 85333 (LIDAR)

Bwlch Height:  288.9m (LIDAR)

Bwlch Grid Reference:  SN 92025 85612 (LIDAR)

Drop:  30.0m (LIDAR) (Sub-Trichant reclassified to Trichant)

Dominance:  9.41% (LIDAR)

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains – Trimble Surveys – Pumlumon

20.04.14  Pen y Clun (SN 926 875)

Pen y Clun (SN 926 875)

After venturing back up to Dinas (SN 904 885) and visiting the proper summit I drove east, past Llyn Clywedog and parked on the grass verge at SN 923 875 adjacent to the bwlch of a 382m map heighted summit which is situated on land named as Pen y Clun.  I inspected the area of the bwlch many a year ago with Rob Woodall whilst visiting three hills with him; our conclusion was that the hill has approximately c 31m of drop.

It only took a few minutes to judge the bwlch and having decided on the spot to place the Trimble I set it up and waited for it to attain the 0.1m accuracy before data can be logged.  This only took a minute or so, and when it was doing its stuff I happily peered through the gloom toward Bryn y Fan (SN 931 884) across the intervening valley.

Not far from the car to the bwlch for this hill.

Once five minutes of data had been gathered at the bwlch I packed the Trimble away and walked up to the summit.  The word ‘fort’ or ‘hill camp’ appears on a number of Ordnance Survey maps adjoined to this hill, and as one can imagine it has the remains of an ancient hill fort on the summit area.

The highest point is easily identifiable and within a few minutes the Trimble was on it gathering its customary ten minutes of summit data, when this was happening I took a few photos and admired the bulk of Bryn y Fan as it shot up in to the sky line across the valley.

The Trimble GeoXH 6000 on the summit gathering data

45 minutes after leaving the car I was back at it, studying the map as I wanted to investigate one more potential new P30 before the predicted afternoon’s rain arrived. 

Survey Result:

Pen y Clun (significant name change)

Summit Height:  381.7m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 92639 87499 (Trimble GeoXH 6000)

Bwlch Height:  350.2m (LIDAR)

Bwlch Grid Reference:  SN 92437 87531 (LIDAR)

Drop:  31.5m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  8.26% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains - Hill Reclassifications – Y Pedwarau

Carreg y Big (SN 902 909) - 400m Sub-Pedwar deletion

There has been a deletion of a 400m Sub-Pedwar by surveying with the Trimble.  The hill was only listed in this sub category as it has a 394m spot height at the bwlch and a 417m spot height at the summit on the Ordnance Survey enlarged mapping hosted on the Geograph website, with these values giving this hill a drop of 23m.  The spot height at the bwlch on the OS map is on a road, and the position of the critical bwlch is higher than this .  The name of the hill is Carreg y Big (SN 902 909) and is situated in the Pumlumon range.

The hill will be deleted from the Y Pedwarau list in the 2^nd edition that will be hopefully be published by Europeaklist.  The list of Pedwar hills is also available from the Haroldstreet website.

The full details for the hill are:

Cardinal Hill:  Foel Fadian

Summit Height:  417.0m (converted to OSGM15)

Name:  Carreg y Big

OS 1:50,000 map:  136

Summit Grid Reference:  SN 902 909

Drop:  19.7m (converted to OSGM15)

The Trimble GeoXH 6000 on the summit of Carreg y Big

For details on the survey that deleted this hill from 400m Sub-Pedwar status please click {here}

Myrddyn Phillips and Aled Williams (April 2014)

Hill Lists – Cymru / Wales – 200m Twmpau updates – Moel Hebog

The first list to the Welsh 200m P30 hills was published on Geoff Crowder’s website v-g.me in 2000; this list preceded the list of TuMPs by nine years, the list proved a very useful resource for the TuMP compilation for this category of hill.

The Welsh 200m P30 list documents all hills in Wales that are at or above 200m in height and are below 300m in height, to qualify for the main list each hill requires a minimum of 30m of prominence.

The hills listed below are updates to the Welsh 200m P30 list originally published on Geoff Crowder's website.  To see the original list click {here}

The original published list had a Sub-List which was entitled ‘Hills to Survey’.  This list consisted of all hills in Wales in the stipulated height band that have a minimum of 20m of prominence, but do not meet the minimum 30m of prominence to enter the main list, according to Ordnance Survey map spot heights and contours.  Nowadays the standard Sub-List takes in all hills that have a minimum of 20m of prominence.  However, the Hills to Survey Sub-List discounted hills whose map spot heights gave a drop value of less than 30m, but more than 20m.  By doing so, the only hills that were Sub-Listed were those that map values dictated stood a chance of entering the main list, for example; if a hill had a summit spot height of 250m and a bwlch spot height of 221m, it was not listed in the Hills to Survey Sub-List as with 29m of drop I thought it did not stand a chance of main list qualification. 

When compiling the Sub-List I was measuring many hills for P30 status using a basic levelling technique, please click {here} for more information concerning this.  I now know that Ordnance Survey spot heights have a standard margin of uncertainty of + / - 3m associated with their accuracy.  Therefore many hills that were not listed in the original Sub-List may have sufficient drop to enter the main list.  Because of this the Sub-List has been altered to include all hills that have a minimum of 20m of drop but are not known to attain the minimum 30m of drop to enter the main list.

The hills listed below are those major amendments to the original Welsh 200m P30 list as it appears on Geoff’s website.  There are many hills that have been promoted from the Hills to Survey Sub-List to the main list, whilst there are many additions to the Sub-List now that it has been standardised to include all 20m minimum but below 30m drop hills.

When the 200m P30 list was first published it was the first to this category of hills and in some way it and its other 100m height band lists paved the way for Clem’s data that later appeared on the RHB file database and then for the TuMPs listing by Mark Jackson.

As well as the first P30 list to this height band the list is now the first to include a comprehensive Sub-List.

TuMP baggers beware; as the main list also includes P30’s not listed by Mark Jackson, so if you want to visit all P30’s you’ll have to include some non TuMPs to do so.

The list will be updated on a weekly basis and will be done so through each Group category, starting from the north and working south.  The second Group that has major updates is Moel Hebog.

Moel Hebog

North of Aberdesach at SH 425 514 continuing north of the Afon Desach and east of the Afon Dwyfach (centred on SH 453 485) to SH 478 372, west of the Afon Glaslyn at SH 582 380 / Afon Colwyn to bwlch at SH 576 514, continuing to Llyn y Gadair (SH 568 521) and the Afon Gwyrfai to Foryd Bay (SH 454 591).  Bordering with Yr Wyddfa to the north, Pen Llŷn to the west and the Moelwynion to the east.

Twmpau - 200m updates

Moel Isallt    286m    SH 537 445

Another hill that was always a prime candidate for promotion from the sub-list and with the large scale Ordnance Survey mapping on the Geograph website giving a 252m spot height on the area of the bwlch it gives this hill 34m of drop.

Moelfryn    277m    SH 568 511

With a summit height of 277m and bwlch contouring between c 240m – c 250m, with the hill to hill contouring being relatively close when compared to the valley to valley contouring, this hill was always a prime candidate for promotion from the sub-list and with an estimated bwlch height of c 247m, it enters the list with c 30m of drop.

Sub-Twmpau - 200m updates

Bryn Cwellyn    c 272m    SH 564 536

A forested summit near to Llyn-y-forwyn which has an estimated summit height of c 272m (a separate point at SH 56454 53329 is estimated as c 271m) and an estimated height at Bwlch y Moch (SH 561 540) of c 252m, giving a drop of c 20m.

Craig Isallt    233m    SH 532 449

With a summit height of 233m and an estimated bwlch height of c 213m, this hill just makes it in to the sub-list with c 20m of drop.

Next update due on the 28^st April 2014