Monday, 31 August 2015

Mapping Mountains – Significant Height Revisions – Y Pedwarau


Mynydd Poeth (SH 953 513)

This is the twelfth post under the heading of Significant Height Revisions, and the following details are retrospective as the Trimble survey that resulted in this height revision was conducted on 24th December 2014.

The twelfth major height revision initiated from a survey with the Trimble GeoXH 6000 was conducted in the Mynydd Hiraethog hills in north Wales on Christmas Eve, in the company of Mark Trengove who had suggested the walk.

The hill appeared in the listing of Y Pedwarau as a Sub-Pedwar with c 29m of drop and was reclassified to a Pedwar due to the survey with the Trimble.  The hill can be easily accessed from the B4501 which skirts its eastern fringes, and is situated just to the north of Cerrigydrudion and to the south of the Alwen Reservoir.

The name of the hill is Mynydd Poeth and its summit height has been increased from its current Ordnance Survey map height, as prior to the survey with the Trimble GeoXH 6000 the hill was listed with a summit height of 417m based on the spot height that appears on current Ordnance Survey maps.  However, higher ground exists to the north of where the 417m spot height appears on the ground.

Therefore this hill’s new summit height is 419.3m (converted to OSGM15) which is 2.3m higher than its previously listed height which came from the 417m spot height on current Ordnance Survey maps.

This hill is one of the rare few that can claim a Hill Reclassification, Summit Relocation and a Significant Height Revision all from the one survey.


The full details for the hill are:

Cardinal Hill:  Mwdwl Eithin

Summit Height (New Height):  419.3m (converted to OSGM15)

Name:  Mynydd Poeth

OS 1:50,000 map:  116

Summit Grid Reference:  SH 95375 51301
  
Drop:  31.7m


Gathering data from the summit of Mynydd Poeth which resulted in this hill's significant height revision

For details on the survey that significantly revised the summit height of this hill please click {here}


Myrddyn Phillips and Aled Williams (December 2014)

Sunday, 30 August 2015

Mapping Mountains – Trimble Surveys – Carnedd Wen


08.08.15  Flat Field (SJ 198 136) and Y Gaer (SJ 204 155)  

After visiting Gaer Fawr Hill (SJ 224 130) and Pt. 172m (SJ 214 125) we drove north and parked close to a gate to the north-west of our next summit.  This hill is listed as Bryn Pentre’r-beirdd in the P30 list that appears on Geoff Crowder’s v-g.me website and is another invented name partly based on the land to the west of this hill’s summit, it is now listed by the name of Flat Field, which was derived from the Tithe map.

The plan for today was suggested by Alex and as we examined the maps the previous evening this hill missed our clutches as it appears on the Ordnance Survey number 239 1:25,000 map, whilst all others for today’s little adventure appear on map number 240.  But as it was very near to our onward route between Pt. 172m and Y Gaer we thought it had better be included.

When we got out of the car we contemplated heading over a field to a large mast which is situated adjacent to a small, thin conifer plantation, this would involve sneaking up the hill from its rear, but straight in front of us was a gate which looked as if it led to another gate and this would then give us access to the upper field where the summit was. 

Without any more hesitation we were off and over a couple of gates, as we walked toward the summit the adjacent field had a small flock of Jacob sheep in it, an unusual site for this part of mid Wales.

Jacob sheep, an unusual site on the hills of mid Wales

Nearing the top a few horses looked up from their contented grazing as Alex marched ahead to find where the high point lay, considering the area of the field this proved relatively easy to determine.  Once we were happy with where the summit was situated the Trimble was set-up and gathered its customary five minutes of data.  During this we stood back and admired the view, and from this particular summit the view is extensive with Cadair Idris prominent on the horizon.

Gathering data from the summit of Flat Field with Cadair Idris prominent in the background

Hoping the horses wouldn't come any closer

It was a marvellous place to be, so near the A490 but in another aspect, so far removed from it as the landscape of summer stretched out for miles around.  As the Trimble was packed away we retraced our inward route back to the car.

We then pushed farther north travelling a couple of miles to Hale Farm and the road junction at Trefnanney.  Our next objective was Y Gaer, which as it name implies was once an ancient hill fort.  The current Ordnance Survey 1:25,000 map has two uppermost 125m ring contours for this hill, these are bisected by a narrow lane that heads straight between them on the ridge, with the westerly of the two ring contours being by far the largest.

We parked next to the gate which gives access into the field where the summit of the westerly ring contour is positioned, Alex headed off toward the summit as a herd of cows ran to and fro around the field.  Ahead of us lay a round concrete structure seemingly placed at the summit of the hill, this is indicated on the map with a small black circle, it is no doubt some form of covered reservoir.

Alex heading for the summit of Y Gaer

We both walked up to its raised base and walked around it, this seems to be quite natural when bagging hills as I’ve noticed in the past that even when the uppermost part of a hill has a covered reservoir on it I have a compunction to get to its top, and that compunction was no different today.

The base of the concrete structure was earth and had been trampled by cows whose hoof prints were on show.  I wondered about placing the Trimble below this earthen walk way but the ground all went up toward it, so not wanting to prolong the debate I found the high point at the base of the concrete sides and gathered another five minutes of data.  During this Alex sat, admired the view and ate a butty as the cows scampered from one side of the field to another.

Gathering data from the summit of Y Gaer

The view eastward from the summit of Y Gaer

As we left the summit and walked the short distance back to the car I looked out toward the ground at the top of the other 125m ring contour, we drove the short distance down the road and with a bit of prompting decided to visit its high point, I didn’t Trimble it as we had to press on as there were many other P30s on our bagging agenda, and as Alex quite rightly said, this hill is only a few minutes down the road from where I live and I can come here and Trimble it in the near future if the inclination to do so is there.

Next on the agenda were two hills with a 154m summit height and their slightly higher 162m neighbour, all closely arranged in a neat triangle, but these will be for the next Trimbling blog post.


Survey Result:



Summit Height:  234.0m (converted to OSGM15)

Summit Grid Reference:  SJ 19845 13602

Drop:  41m

Dominance:  17.52%



Y Gaer

Summit Height:  130.5m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SJ 20413 15563

Drop:  c 39m

Dominance:  29.90%


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




Saturday, 29 August 2015

Mapping Mountains – Significant Height Revisions – 200m Twmpau


Pen y Berth (SJ 081 127)  

This is the eleventh post under the heading of Significant Height Revisions, and the following details are retrospective as the Trimble survey that resulted in this height revision was conducted on 19th October 2014.

The eleventh major height revision initiated from a survey with the Trimble GeoXH 6000 was conducted in the lower Berwyn hills in the company of Mark Trengove on a colourful autumnal day in October.

The hill can be accessed from 1km east of the small community of Dolanog on a track that heads north-west and then east to sneak up to the summit from the opposing side of the hill.  The summit area of the hill is given two 280m uppermost ring contours aligned east and west of one another on Ordnance Survey maps, with each contour ring given a 282m spot height that appears on the Ordnance Survey enlarged map on the Geograph website.

The name of the hill is Pen y Berth and the following results were those obtained with the Trimble GeoXH 6000 for the two points surveyed:

Eastern 282m spot height:  283.7m (converted to OSGM15) at SJ 08322 12748

Western 282m spot height at SJ 08012 12780 not surveyed

Easterly high point of western 280m ring contour:  287.5m (converted to OSGM15) at SJ 08126 12730


The land at SJ 08126 12730 was visually judged to be higher than the land at SJ 08012 12780, therefore this latter position was not surveyed.  The height given the hill on current Ordnance Survey maps is 282m, with the height resulting from the survey with the Trimble being 287.5m.

Therefore this hill’s new summit height is 5.5m higher than its previously listed height which came from the 282m spot height on the Ordnance Survey enlarged map on the Geograph website.


The full details for the hill are:

Cardinal Hill:  Carreg y Big

Summit Height (New Height):  287.5m (converted to OSGM15)

Name:  Pen y Berth

OS 1:50,000 map:  125

Summit Grid Reference:  SJ 08126 12730 
 
Drop:  134.2m

Dominance:  46.68%


Pen y Berth (SJ 081 127) - a hill that's had it's height significantly revised

For details on the survey that significantly revised the summit height of this hill please click {here}

Myrddyn Phillips (October 2014)




Friday, 28 August 2015

Mapping Mountains – Trimble Surveys – Carnedd Wen


08.08.15  Gaer Fawr Hill (SJ 223 129) and Pt. 172m (SJ 214 125 – not Trimbled)  

Gaer Fawr Hill (SJ 223 129)

A hill bagging day in the company of Alex Cameron which concentrated on summits, so the more esoteric side of surveying bylchau would have to wait another day.  The singular traverse of the summits started on the outskirts of Cegidfa (Guilsfield) and continued through the small community of Deuddwr, before heading toward the land above Llanymynech and ending up on the outskirts of Oswestrry (Croesoswallt).

Our first hill of the day is a rather stunning little gem; Gaer Fawr Hill, this hill is positioned on the outskirts of Cegidfa (Guilsfield) and is heavily wooded.  It is a hill that I have seen on countless occasions but up until today, never visited.

We parked at the top of the Gwreiddyn Lane at SJ 219 125 where three or four cars can be left in the area of a small disused quarry.  This is an official parking place as two paths start from it, both heading in opposing directions around the hill.

Gaer Fawr dates from around 800BC with work continuing on it for another four centuries, and originated as a small summit fort that over time was extended, taking in two massive entrance ways created with graded approach ramps and defended gateways.  The construction has up to five lines of ramparts over 8m (26ft) high.  Much of this is now swamped in undergrowth with the whole area of 5.8 hectares (21 acres) covered in woodland.

Information board showing an artist's impression of Gaer Fawr

We followed the northern path which gains steady height around the western fringes of the hill, the sun shone from a blue sky and occasional bird song sprang from our surrounds.  Occasionally small animal paths tempt you straight up the hill but we continued on the main path as it swung around to the north-west of the summit.

Heading toward the summit of Gaer Fawr

It seemed that we had this rather special place all to ourselves as the world went about its business below.  Nearing the top the path reaches a relatively flat area where a beautiful terracotta wild boar is on display, this is perched on the ground beside a secret gateway into a tree in the form of a very small door.  The statue commemorates a small hollowed bronze boar which was found at, or near to, the hill fort, this is now displayed in the National Museum of Wales.

Statue commemorating the hollowed bronze boar of Gaer Fawr

The secret doorway

Only a short distance from the rather beautiful piggy is the summit area of the hill, part of this consists of a small open space where a single tree is guarded by a stone circle which has been laid around its base, this is not ancient or in the form of what we would consider a stone circle, but more a laying of small rocks around the tree, however it does give an added mysteriousness to the place as do a number of objects that hang from the lower branches.

Tree with stone circle

Alex and I assessed the land around this tree and an area about 60 metres from it which was more overgrown but which we considered higher.  I placed the Trimble on the top of my rucksack to give it elevation above the undergrowth and the waiting game began.  After 10 – 15 minutes it had crept down to 0.12m accuracy and a short time later I pressed ‘Log’ and it started gathering data. 

Gathering data from the summit of Gaer Fawr Hill

On the periphery of the summit area the land plunged down into sunshine which occasionally broke through the canopy of trees, with the whole place being peaceful and seemingly forgotten.

Sunlight through the canopy of trees

Once five minutes of data were collected we measured the offset as o.45m which will be taken off the processed result, and I packed the equipment away.  Our descent was on the south-western path which headed straight down to the awaiting car.

Once back at the car we looked at the land on the opposite side of the lane as this led up to our next summit, Alex contemplated a direct approach through forestry.  I favoured a simpler, albeit less exciting approach via a footpath to the north of the hill.  Thankfully we decided on the latter and jumped in the car to drive north and then westward to park in a small pull-in spot.

Our next hill is listed as Bryn Trawscoed-hen in the P30 list that appears on Geoff Crowder’s v-g.me website, this is an invented name and is partly taken from the farm just to the south-west of the hill’s summit. 

Pt. 172m (SJ 214 125)

By the time we had walked up the lane to a track which led through the yard of Trawscoed Farm the morning had warmed up and the sun started to beat down.  Beyond this farm we had a chose and opted to walk down a field and over a fence that gave us access into another field which led up beside a hedge toward the copse of trees at the summit of this hill.

During this time we kept quiet as we didn’t want to disturb any farm dogs or farmers, once beside the copse of trees we headed toward its corner expecting to find the high point of the hill in a field, clear of trees, as indicated by the placement of the 172m spot height on current Ordnance Survey maps.  We were surprised to find this part of the hill embedded in trees with the wood much larger than indicated on the map. 

As we clambered over a fence past nettles and brambles it was obvious that I would have to forsake having the hill Trimbled as the tree coverage and undergrowth was extensive, I happily took a photo of Alex on what we deemed to be the high point of the hill and out of the wood we scampered.

Alex at the high point of Pt. 172m

Looking back toward the summit

Heading to the track through Trawscoed Farm and back to the car

The view of Gaer Fawr Hill from the track heading to Trawscoed Farm

Our next stop was Y Gaer which is situated to the north of these two hills and its walk and Trimble survey will be described in another blog post.


Survey Result:


Gaer Fawr Hill

Summit Height:  217.6m (converted to OSGM15)

Summit Grid Reference:  SJ 22391 12995

Drop:  c 80m

Dominance:  36.77% (Lesser Welsh Dominant status confirmed)


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



Thursday, 27 August 2015

Mapping Mountains – Significant Height Revisions – Yr Uchafion and 700m Sub-Twmpau


Llechog (SH 606 567) 

This is the tenth post under the heading of Significant Height Revisions, and the following details are retrospective as the Trimble survey that resulted in this height revision was conducted on 9th September 2014.

The tenth major height revision initiated from a survey with the Trimble GeoXH 6000 was conducted in the hills of the Yr Wyddfa range in the heartland of Eryri on a beautiful sunny September day.

The hill can be accessed from the Llanberis Path which is one of the six main paths up Yr Wyddfa.  This path roughly follows the course of the railway line as it ascends the mountain from Llanberis, and the hill stands on a ridge that is seldom visited by the multitude of walkers who head toward the summit of Wales’ highest mountain.

The name of the hill is Llechog.  The height given the hill on current Ordnance Survey maps is 718m, with the height resulting from the survey with the Trimble being 720.0m (converted to OSGM15).  This is not a dramatic height revision but it does come within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term ‘significant height revision’ applies to any listed hill whose Ordnance Survey summit spot height has a 2m or more discrepancy when compared to the surveyed Trimble height, also included are hills whose summit map data is missing an uppermost ring contour when compared to the data produced by the Trimble.  As heights on different scaled Ordnance Survey maps are not consistent the height given on the 1:25,000 map is being prioritised for detailing these revisions.

Therefore this hill’s new summit height is 2.0m higher than its previously listed height which came from the 718m spot height on current Ordnance Survey maps.


The full details for the hill are:

Cardinal Hill:  Yr Wyddfa

Summit Height (New Height):  720.0m (converted to OSGM15)

Name:  Llechog

OS 1:50,000 map:  115

Summit Grid Reference:  SH 60613 56751
  
Drop:  28.0m


Gathering data from the summit of Llechog which resulted in this hill's significant height revision

For details on the survey that significantly revised the summit height of this hill please click {here}

Myrddyn Phillips and Aled Williams (September 2014)




Wednesday, 26 August 2015

Mapping Mountains – Trimble Surveys – Carnedd Wen


07.08.15  Yr Allt (SJ 242 100)  

Yr Allt (SJ 242 100)

The start of a two day bagging extravaganza with Alex Cameron, with the first day a very leisurely affair and with tomorrow planned as a multi bagging day.  I met Alex at Welshpool Railway Station and after dropping off his stuff at my bungalow we headed toward the canal tow path which is adjacent to where I live.

Our hill for the day was Yr Allt which is listed as a Hump and 200m Twmpau, the last time I had visited this hill was in December of last year when the sky was blue and an early morning chill pervaded the land, today the summer growth had changed the landscape and the greens predominated.

As we walked briskly on the tow path a mother Morehen and accompanying chick stood on a small reed bed that floated on the canal water with their reflections caught below. 

Mother and chick on a small reed bed

Only an occasional glimpse of our objective could be seen as it was mainly shielded from view by copious amounts of summer vegetation, which is now almost at its limit of growth.  This often amazes me in a similar way to the rusted and yellowed colour of moor grass in the Autumn time, as just when you think the colour cannot get any more radiant it continues to aflame and intensify, and now as summer ebbs into its lateness, the growth still amazes as it cascades from hedgerows and gardens and continues to do so even when one thinks it is at its limit.

As we continued on the tow path a kayak passed with a man and woman making swathes in the water with their oars, a fleeting glimpse of movement on an otherwise becalmed land as both water and air were tranquilly silent this morning.

A peaceful way to spend a day

By now the conversation flowed with all manner of hilly related subjects being talked about, and as we neared the Pool Quay Lock we now had a choice of route, either past Dyers Farm which is the way I normally head when on this walk, or continue north and aim for a friend’s house to see if we could sit, rest and have a cuppa, we decided on the latter and walked over a small footbridge to the opposite side of the canal and then over fields toward the Coppice Lane.

Nearing the Pool Quay Lock

Across the Severn Valley the Breiddin stood aloof with their distinctive profile dominating the flatlands of the flood plain, its dulled greens of trees set against the illuminated greens of pasture, reed and hedgerow, all succulently ablaze with growth.

Moel y Golfa, aloof above the flood plain

Our onward route took us through a field of maize which stood tall and overshadowed our progress.  As we approached my friend’s house I wondered if anyone would be in, I knocked the door and Ffion skipped through the kitchen and opened it, it was lovely to see her and especially so when she invited us in and asked if we would like a cup of tea.

Through the field of maize

Ffion is one of two daughters of Geraint and Verity, I’ve known Geraint most of my life but we now only occasionally see one another.  We sat and chatted and caught up with news and all too soon it was time to press on toward the top of the Coppice Lane.

Ffion gave us a lovely welcome

Toward the top of this lane is Coppice East Farm, where I used to live many a year ago.  As we approached we met the present occupant who we stopped and chatted to, it wasn’t the first time this had happened, as I’d stopped for a chat when doing this walk and visiting the top of Yr Allt with Mark Trengove a couple of years ago.

Plaque on the side of Coppice East Farm

Coppice East Farm

Our walk was now getting seriously leisurely as this chat continued for quite some time and continued to do so when her husband joined us.  After about 15 minutes Alex and I said our goodbye’s and headed up the track past the Gamekeeper’s House, beyond is a footpath which gives access onto the upper part of the hill.

As we approached this hill’s trig pillar the view opened out and once the customary photos were taken we sat in the sun, ate a butty and chatted.  This trig pillar is not positioned on the high point of Yr Allt, this is situated across an intervening dip of land adjacent to the Allt Wood.

The trig pillar with the Breiddin in the background

The land at the top of the hill has two distinct possibilities for the accolade of the very highest point, I couldn’t remember which one I had Trimbled on my last visit, but once the two of us had crept around with our chins almost on the ground assessing the lay of land we decided where the Trimble should be set up and it subsequently gathered five minutes of data.

Gathering data from the summit of Yr Allt

All that remained was a leisurely stroll down the hill passing a grazing flock of sheep and coming across a large mushroom that resembled the face of an owl.  As we reached the Rhallt Lane we followed it down to the canal and walked back on the tow path toward Weshpool.

Just turned out onto the hill

Mushroom as Owl, with the nose cone added by Alex

The ascent to the summit of Yr Allt had taken five hours, whilst its descent just over one hour, Alex commented that if all his walks were this leisurely his Tump totals would start to stagnate!


Survey Result:

Yr Allt

Summit Height:  231.3m (converted to OSGM15)

Summit Grid Reference:  SJ 24240 10005

Drop:  105.2m (converted to OSGM15) (Hump status confirmed)

Dominance:  45.48% (Lesser Welsh Dominance status confirmed)
 


For the blog post on the bwlch survey of Yr Allt please click {here}

For the blog post on the 1st summit survey of Yr Allt please click {here}


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




Tuesday, 25 August 2015

Mapping Mountains – Significant Height Revisions – Y Pedwarau


Bryn Melyn (SO 109 184)

This is the ninth post under the heading of Significant Height Revisions, and the following details are retrospective as the Trimble survey that resulted in this height revision was conducted on 22nd July 2014.

The ninth major height revision initiated from a survey with the Trimble GeoXH 6000 was conducted in the hills of the Bannau Brycheiniog (Brecon Beacons) in south Wales, in the company of Mark Trengove who had suggested the walk.

The hill appears in the listing of Y Pedwarau and can be easily accessed from the end of a minor road above the waters of the Talybont Reservoir which is situated in Glyn Collwn.  The hill can also be accessed from its opposing valley of Dyffryn Crawnon which gives a slightly more rewarding and lengthy walk.

The name of the hill is Bryn Melyn and its summit height has been increased from its current Ordnance Survey map height, as prior to the survey with the Trimble GeoXH 6000 the hill was listed with a summit height of c 446m based on it having an uppermost contour ring of 440m on current Ordnance Survey maps.  Its new summit height is 450.5m (converted to OSGM15) which is 4.6m higher than its previously estimated height and 10.5m higher than its uppermost ring contour on current Ordnance Survey maps.


The full details for the hill are:

Cardinal Hill:  Pen y Fan

Summit Height (New Height):  450.5m (converted to OSGM15)

Name:  Bryn Melyn

OS 1:50,000 map:  161

Summit Grid Reference:  SO 10941 18432
  
Drop:  38.6m


Gathering data from the summit of Bryn Melyn which resulted in this hill's significant height revision

For details on the survey that significantly revised the summit height of this hill please click {here}

Myrddyn Phillips and Aled Williams (July 2014)