Mapping Mountains – Trimble Surveys – Cilfaesty

 

14.07.21  Cold Weston (SO 141 907) 

LIDAR image of Cold Weston (SO 141 907)

Cold Weston; a name derived from the Tithe map, is similar to many hills of comparable height with its upper field used for pasture.  Many such hills are not dramatic in nature, but they are well worth visiting and if time permits, also exploring, as they usually have a quiet ambiance with many affording excellent views, and this hill was no exception.  However, one difference being is that the local farmer accompanied me to the summit of this hill and helped find its high point in the long summer grass. 

I contemplated approaching this hill on a public footpath from the north-west but decided to drive up the access track to Weston farm to ask permission to park and visit the high point of the hill.  The farm is positioned just below the summit to its south. 

This hill was the fourth of a planned seven during the morning and early afternoon, as I wanted to leave the hills before conditions became too warm and driving to just below the summit was a good way to shorten this particular walk. 

Prior to visiting this hill I had analysed it via LIDAR and build up contours until a single point gave its summit position.  Its bwlch is not yet covered by LIDAR, therefore for listing purposes its bwlch height, at the present, is reliant upon a 237m spot height that appears on the Ordnance Survey 1:50,000 Landranger map. 

My day’s route was taking me from just east of Kerry, winding its way back and forth across the intervening A489 road and ending on Trehafren Hill (SO 100 910), which is positioned in Newtown.  I had only previously visited the last planned hill, so all others were new to me, and even though these hills are relatively small in height it is the exploration and investigation that I enjoy and this is enhanced when visiting new ground. 

As I left the main road I turned right on to a minor lane and then immediately right again on the gravelled track leading to Weston farm.  I had only driven a few metres up the track before I spotted a tractor in the adjacent field cutting silage; I stopped and waved over to it.  I was soon in conversation with Edward Jones who kindly gave permission to park at his farm to visit the hill, before leaving he asked if I could call at the farm house as his wife may wonder what I was doing. 

Donna Jones of Weston farm

I continued up the track and soon parked in the farm yard.  As I left my car, Donna; Edward’s wife, was walking down toward me, I waved and we chatted for a number of minutes.  I explained what I hoped to do and she said ‘follow me’ and away we went past the farm house to a gate giving access up a field to another gate, beyond which was the upper field where the summit is situated. 

It’s only on occasion that I end up on a summit with a local farmer and such an opportunity is one to relish.  I stood on top with Donna with the two of us assessing the summit area of the hill for its highest point before I placed the Trimble atop my rucksack to gather data. 

Gathering data at the summit of Cold Weston

During data collection we stood below the equipment chatting away about all manner of things.  Once allotted data were gathered and stored I closed the equipment down and took a few photographs of Donna on the summit beside the Trimble. 

Donna Jones at the summit of Cold Weston

The view from the top took in the whole of Newtown and down the Severn Valley to the Breiddin close to Welshpool and the higher hills to the west.  It was a wonderful summit to stand on and talk with the local farmer, the opportunity to do so doesn’t occur very often, but when it does it is always welcome. 

 

Survey Result: 

 

Cold Weston (significant name change)

Summit Height:  306.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 14188 90749 (Trimble GeoXH 6000)  

Bwlch Height:  237m (spot height)

Bwlch Grid Reference:  SO 13525 90858 (spot height)

Drop:  69m (Trimble GeoXH 6000 summit and spot height bwlch)

Dominance:  22.54% (Trimble GeoXH 6000 summit and spot height bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

Mapping Mountains – Trimble Surveys – Pumlumon

11.07.20  Mynydd Derw Llwydion (SN 904 900)  

Mynydd Derw Llwydion (SN 904 900)

This hill is positioned close to Llyn Clewedog and the various pull-ins and picnic tables overlooking the lake were busting with life as I drove around it, it seemed the lifting of the 5-mile keep local restriction had encouraged many people to get out and especially so with the weekends weather forecast giving dry and sunny conditions throughout Wales.  I headed away from the picnickers and parked at the start of the track leading toward the single wind turbine atop this hill.

The track leading to the summit

It was 1.15pm as I parked my car and headed off with all necessary equipment up the track toward the single wind turbine on the summit of Mynydd Derw Llwydion.  I’d been this way before in April 2014 when on a walk from Llyn Clewedog to Staylittle visiting and surveying a number of hills on the way.  The point I’d surveyed for this hill’s summit is where the 387m spot height appears on the Ordnance Survey 1:25,000 Explorer map. 

The survey of this hill’s summit and bwlch resulted in it being promoted to P30 status.  However, since those days LIDAR is now available and this shows the summit of this hill is close to the single wind turbine and not where the spot height is positioned, so a re-visit was necessary.

LIDAR summit image of Mynydd Derw Llwydion

It was only a five minute stroll to the summit and by the time I arrived on the high pint a welcome breeze blew across the land.  After assessing the summit area I chose the spot for Trimble placement and once the 0.1m accuracy level was attained I pressed ‘Log’ and scampered off to wait for the allotted five minutes of data to be gathered and stored.

Gathering data at the summit of Mynydd Derw Llwydion

Reversing my inward route I was soon back at my car, changed and away toward Llanidloes and a socially distanced visit to see Eryl and Rita for a couple of hours catch up sitting in the sun, a fine way to spend an afternoon.

Survey Result:

Mynydd Derw Llwydion  

Summit Height:  389.3m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SN 90460 90041 (summit relocation confirmed)

Bwlch Height:  358.1m (converted to OSGM15) (from previous Trimble GeoXH 6000 survey)

Bwlch Grid Reference:  SN 90391 90264 (from previous Trimble GeoXH 6000 survey)

Drop:  31.3m (Sub-Trichant reclassified to Trichant)

Dominance:  8.03%

For details on the Trimble GeoXH 6000 survey of this hill’s bwlch

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains – Trimble Surveys – Carnedd Wen

06.06.20  Y Golfa (SJ 182 070), previously Trimbled

Y Golfa (SJ 182 070)

When Aled and I stood atop Pen y Cerrig Serth on the 19^th January earlier this year I couldn’t foresee this as the last summit I would visit for almost five months.  The intervening time has brought a pandemic, the likes of which has not been seen for over 100 years.

The Coronavirus; Covid-19 has killed over 400,000 people worldwide and over 40,000 of these in Britain, and to combat its spread a lock down was instigated on the 23^rd March.  This is slowly being lifted throughout Britain, with firstly England taking the plunge of opening up with the other constituent countries of the UK being more circumspect.

Throughout the last 2½ months I’ve followed instructions and not travelled to take the allotted daily exercise instructed by the Welsh Government.  Therefore any exercise I’ve taken is from my own doorstep and hill walks farther afield must wait until the countryside is once again open.

Although many of the instructions due to the outbreak of Covid-19 are harsh, they are understandable and necessary.  This has obviously limited everyone’s hill walking, or at least those who have abided the instruction, as some unfortunately haven’t.

The outbreak and resulting limited scope for hill walking has reconnected me to my local landscape and enabled late evening walks from my doorstep, mainly using the towpath beside the Montgomeryshire Canal for access to the countryside.  But until this evening I had not visited a summit of a hill.  Over the last 2½ months I’d looked toward a variety of hills from elevated views above Welshpool as the main Berwyn ridge distantly looked back at me, and the Breiddin, Cefn Digoll, Yr Allt, Moel y Garth, Upper Park and Y Golfa all were on grand display.  These hills were always on show as the sunniest spring since records began gave two months of sunshine and increasingly warm temperatures.  However, the weather has now broke and rain has recently set in, with the temperature giving cooler conditions, and although this afternoon gave showers, the forecast for the evening was good.

I’d recently investigated public footpaths connecting the Frochas Lane with the estate grounds of Llanerchydol, and now wanted to use the latter as an ascent route to the summit of Y Golfa, which I had done on two previous occasions, the last of which when I Trimbled its summit in August 2014.

Setting off at 6.55pm the canal towpath gave access to the Back Lane which leads toward the Raven roundabout and the paved road heading west out of the confines of Welshpool, to the quiet pastured old estate grounds of Llanerchydol Hall.  As ever it was good to be out and especially so during an evening, which I rarely do when hill bagging.

The pleasantly warm conditions and cloudless deep blue skies of the last two months had been replaced with bubbled cloud and a cooling evening.  I hoped that I could watch a lowering sun from the summit before scampering off to find a descent route enabling a circular walk before darkness overtook me.

Upper Park on the left and Cromwell Hill on the right

The paved road leading through the old estate grounds gives a tranquil ascent route with grazing sheep and inquisitive cows a plenty.  This soon turns to a vehicle track as it gains height past Home Farm and Pen-y-golfa.  The continuing public footpath then heads across a field and beside the Golfa Wood before leading to a variety of green tracks high on the hill’s eastern flank, each through summered fern and undergrowth.

The Breiddin and Shropshire Plain beyond

Across the valley Upper Park and Cromwell Hill caught the last glimmers of sunlight, whilst farther to the east the Breiddin rose above the Shropshire Plain.  Appearing ahead of me the white trig pillar stood bolt upright signifying the high point of the hill.  I had hoped that low light would cast illuminated colour on the trig giving me opportunity for a number of photos framing it in the foreground with distant views beyond.  As I approached the sun sank behind a cloud bank out to the west leaving dulled colour on the hill.  I had missed my opportunity by no more than a couple of minutes; however I could not linger as it was now 9.00pm and I had to devise a descent route.

The summit of Y Golfa

Below me the Gaer Farm looked an inviting way to connect with the Frochas Lane, so off I scampered on more earthen tracks and narrower footpaths, past manicured golfing greens and eventually down a field to a track, past friendly horses and a relatively recent new paved road heading uphill to The Gaer.  From here I could, if I wanted, remain on a paved road all the way toward Welshpool.  However, I had a number of options available to connect with my home town, and one involved using the public footpath I’d recently been on that heads across fields to Lower Llanerchydol, this would also give me the shortest and quickest route back.

It was 10.00pm as I scampered across the fields toward Lower Llanerchydol.  The sun had sunk, leaving delicate mauved clouds peering across the sky.  The paved road through the old estate took me down to the Raven roundabout and the Back Road through Welshpool and finally the canal towpath where I was accompanied by dancing bats on my way back home.  Arriving at my front door I looked at my watch, it was 10.40pm; it was time for a large mug of tea and a contented sleep.

LIDAR image for the bwlch of Y Gofa

The following day I checked the Trimble result for the summit and examined the area of this hill’s bwlch via Google Maps before downloading LIDAR to see if the bwlch was covered.  It was, just.  I then spent an inordinate amount of time building up LIDAR contouring and comparing this to the digitised image on my laptop via the Google car.

The bwlch of Y Golfa, with the critical point just through the gate on the left, and across the field toward the fence.  Photo:  Google Maps

The contrast between a hill walk to a summit where data is then gathered and stored in the Trimble GeoXH 6000 and producing the same via LIDAR on a laptop is extreme.  One gives beauty and the other involves staring at a screen whilst tapping endlessly on a keypad.  However, the end result is accurate numerical data and this is presented below.

Survey Result:

Y Golfa

Summit Height:  341.4m (from previous Trimble GeoXH 6000 survey) 

Summit Grid Reference:  SJ 18247 07086 (from previous Trimble GeoXH 6000 survey) 

Bwlch Height:  175.1m (LIDAR)

Bwlch Grid Reference:  SJ 16645 06017 (LIDAR)

Drop:  166.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  48.72% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For details on the summit survey of this hill

For further details please consult the Trimble Survey Spreadsheet

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

Yr Arddu (SH 626 462) – Sub-Trichant addition

There has been 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 spot heights on contemporary Ordnance Survey maps.

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 13th May 2017.

The name the hill is listed by is Yr Arddu, and it is adjoined to the Moelwynion group of hills which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with the A498 road to its north-west and the A4085 road to its south-west, and has the village of Beddgelert towards the west north-west.

When the original 300m height band of Welsh P30 hills were 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. 

When the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with an estimated c 26m of drop, based on the 389m summit spot height that appears on the Ordnance Survey 1:50,000 Landranger map and an estimated bwlch height of c 363m based on interpolation of 10m contouring between 360m – 370m.

Extract from the Ordnance Survey 1:50,000 Landranger map

The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which is entitled the Interactive Coverage Map became available online.  This mapping had many spot heights not on other publicly available Ordnance Survey maps and included a 362m spot height on the area of this hill’s bwlch.  This spot height is also shown on Ordnance Survey data that appears on the Magic Maps website. 

Extract from the Magic Maps website

Therefore, the addition of this hill to Sub-Trichant status is due to spot heights on contemporary Ordnance Survey maps, resulting in a 389m summit height and a 362m bwlch height, with these values giving this hill 27m of drop which is sufficient for it to be classified as a Sub-Trichant.

The full details for the hill are:

Group:  Moelwynion

Name:  Yr Arddu

OS 1:50,000 map:  115

Summit Height:  389m (spot height)

Summit Grid Reference:  SH 62652 46230 (spot height)

Bwlch Height:  362m (spot height)

Bwlch Grid Reference:  SH 62863 46313 (spot height)

Drop:  27m (spot heights)

Myrddyn Phillips (February 2020)

Mapping Mountains – Trimble Surveys – Pumlumon

23.07.19  Y Gribyn (SN 924 918)

LIDAR image of Y Gribyn (SN 924 918)

With predicted temperatures in the 30s it wasn’t a day to spend hours on the hill multi-hill bagging.  Just one would suffice, ideally relatively low in height, not far to walk, but a walk that had variety and gave good views.  Y Gribyn ticked all these and as it was only a couple of miles from where I met Suzanne in Llanidloes it proved an ideal hill for the day.

Prior to the walk I had LIDARed the summit and connecting bwlch of this hill and with ten figure grid references noted, I met Suzanne in Llanidloes at just past 9.00am.  She arrived with a car full to busting for her impending move in to her new flat, and with a 4.00pm appointment to pick the keys up it meant we were in no rush, so a leisurely vegetarian breakfast in the Great Oak café and a wander in to a charity shop and the Great Oak bookshop could be enjoyed.

By the time we had found a parking place up valley from the small community of Llawr-y-glyn the temperature was roaring upward and blue skies pieced all around and a multitude of hues of green cascaded from the summer growth.  It was a good day to be out!

Our route took us a few metres up the continuation of the paved lane where a public footpath entered Coed y Gribyn on our right.  The path through the wood proved delightful with dappled sunshine swaying shaded patterns on dead leaf foliage which lay on dried earth forming a soft blanket to our slow uphill progress.  It was a day not to be rushed and any stop was welcome.

The initial path through Coed y Gribyn

The path led diagonally up through the wood gaining height at a steady gradient, before it emerged in to the glare of heat where a fence led to a gate which gave access to the field where the connecting bwlch of Y Gribyn is situated.  As I headed toward the point to survey with Trimble in hand directing me via the ten figure grid reference produced from LIDAR analysis, Suzanne stood in the sun with her newly fashioned swishing stick away from where the Trimble was soon to be placed.

On the higher part of the path through Coed y Gribyn

As the Trimble beeped away gathering bwlch data I joined Suzanne and waited whilst the equipment did its stuff.  Once the allotted data were gathered and stored I switched it off, took a few photos and re-joined Suzanne who was heading toward the gate which gave access toward a track that swung around the western side of the upper section of the hill.

Gathering data at the bwlch of Y Gribyn

Leaving the track the summit rears up just beyond a small quarried area, its high point consists of cropped grass and flinted rock and is a part of an attractive small ridge that descends southward.

Suzanne heading toward the summit of Y Gribyn

As the Trimble gathered summit data we sat in the sunshine chatting and enjoying the extensive view down the valley toward Trefeglwys, with Bryn y Fan prominent to our south.  Once allotted data were stored the warm conditions and view dictated another laze in the sunshine.  It proved a struggle to get back up.

Gathering data at the summit of Y Gribyn

Distant views of Bryn y Fan

Contemplation

Leaving the summit we re-joined the gravelled track which soon joined the narrow paved lane leading down toward the old, but now renovated, buildings of Y Gribyn, where I made place-name enquiries and with the hill confirmed as the same as that of the old farm, we continued on a public footpath re-claiming lost height to the corner of a field where Coed y Gribyn plunged steeply down to the narrow lane where the car was parked.

Summer grasses

All that remained was to find the continuation of the footpath as it entered the wood, which we did, and down we happily walked on a narrow path that must seldom be used, but which was beautiful as it tranquilly swept down through open deciduous trees with dappled light swaying to the rhythm of breeze blown sunshine, twas good to be out.

Survey Result:

Y Gribyn

Summit Height:  347.8m (converted to OSGM15)

Summit Grid Reference:  SN 92439 91802

Bwlch Height:  314.0m (converted to OSGM15)

Bwlch Grid Reference:  SN 92376 91952

Drop:  33.7m

Dominance:  9.70%

For further details please consult the Trimble Survey Spreadsheet

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