Mapping Mountains – Hill Reclassifications – 100m Twmpau

Bryniau (SH 579 711) – 100m Sub-Twmpau reclassified to 100m Twmpau

There has been confirmation of a reclassification to the list of 100m Twmpau, with the summit height, bwlch height and their location, the drop and status of the hill derived from a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis conducted by Myrddyn Phillips.

LIDAR image of Bryniau (SH 579 711)

The criteria for the list that this hill reclassification applies to are:

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Glyder Fawr 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 A4087 road to its west and minor roads to its south and east, and has the small city of Bangor towards its north.

When the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the Hills to be surveyed sub list that accompanied the 100m height band of P30 hills as it did not at that stage meet the criteria used in this list.

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

When the sub list was standardised, and interpolated heights and drop values also included this hill was listed with an estimated c 30m of drop, based on the 117m spot height adjoined to a triangulation pillar positioned at SH 57894 71129 and an estimated c 87m bwlch height, based on interpolation of contouring 5m contouring between 85m - 90m that appears on the Ordnance Survey 1:25,000 Explorer map.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website

The drop value was re-assessed when the Ordnance Survey Interactive Coverage Map became available online via the Geograph website.  This mapping has a 118m spot height positioned to the north-east of the trig pillar at SH 57968 71186, resulting in the drop value remaining at an estimated c 30m with a revised estimated c 88m bwlch height and the summit relocation of this hill.

LIDAR summit image of Bryniau

However, it was not until LIDAR became available that these two positions could be compared and confirmation that the land where the 118m spot height appears is higher than the land beside the 117m map heighted trig pillar and that the hill had sufficient drop to be classified as a P30.

 

The Trimble GeoXH 6000 gathering data at the summit of Bryniau

Therefore, the confirmation of the reclassification of this hill from 100m Sub-Twmpau status is due to a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis, resulting in a 117.6m summit height and an 86.2m bwlch height, with these values giving this hill 31.3m of drop, which is sufficient for it to be classified as a 100m Twmpau.

The full details for the hill are:

Group:  Glyder Fawr

Name:  Bryniau

OS 1:50,000 map:  114, 115

Summit Height:  117.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 57971 71196 (Trimble GeoXH 6000)

Bwlch Height:  86.2m (LIDAR)

Bwlch Grid Reference:  SH 57961 70836 (LIDAR) 

Drop:  31.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Myrddyn Phillips (February 2019)

Mapping Mountains – Summit Relocations – 100m Twmpau

Bryniau (SH 579 711)

There has been a Summit Relocation to a hill that is listed in the 100m Twmpau, with the summit height, bwlch height and their location, the drop and status of the hill derived from a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis conducted by Myrddyn Phillips.

Bryniau (SH 579 711)

The criteria for the list that this summit relocation applies to are:

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Glyder Fawr 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 A4087 road to its west and minor roads to its south and east, and has the small city of Bangor towards its north.

The land where the summit of this hill is situated is a part of Bryniau and this was derived from local enquiry and substantiated from the Tithe map, and it is the name that this hill is now listed by.  The hill is adjoined to the Glyderau group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and is positioned with the A4087 road to its west and minor roads to its south and east, and has the small city of Bangor towards its north.

When the original Welsh 100m P30 list was published on Geoff Crowder’s v-g.me website, the summit location of this hill was given to the 117m spot height adjoined to a triangulation pillar that appeared on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps and which is positioned at SH 57894 71129.

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

The details for this hill were re-examined when the Ordnance Survey Interactive Coverage Map hosted on the Geograph website became available online and this map gives a 118m spot height positioned to the north-east of the trig pillar at SH 57968 71186.

Extract from the Ordnance Survey Interactive Coverage Map hosted on the Geograph website

However, it was not until LIDAR became available that these two positions could be compared and confirmation that the land where the 118m spot height appears is higher than the land beside the 117m map heighted trig pillar.

LIDAR summit image of Bryniau

The summit height produced by the Trimble GeoXH 6000 survey is 117.6m, and its position in relation to that originally listed summit comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

The Trimble GeoXH 6000 gathering data at the summit of Bryniau

Therefore, the summit height produced by the Trimble GeoXH 6000 survey is 117.6m and is positioned at SH 57971 71196, this position is approximately 80 metres north-eastward from where the summit was originally listed at the triangulation pillar.

 

The full details for the hill are:

Group:  Glyder Fawr

Name:  Bryniau

OS 1:50,000 map:  114, 115

Summit Height:  117.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference (New Position):  SH 57971 71196 (Trimble GeoXH 6000)

Bwlch Height:  86.2m (LIDAR)

Bwlch Grid Reference:  SH 57961 70836 (LIDAR) 

Drop:  31.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Myrddyn Phillips (February 2019)

Mapping Mountains – Significant Name Changes – 100m Twmpau

Bryniau (SH 579 711)

There has been a Significant Name Change to a hill that is listed in the 100m Twmpau, with the summit height, bwlch height and their location, the drop and status of the hill derived from a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis conducted by Myrddyn Phillips.

Bryniau (SH 579 711)

The criteria for the list that this name change applies to are:

100m Twmpau - Welsh hills at or above 100m and below 200m in height with 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 100m and below 200m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.

100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Glyder Fawr 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 A4087 road to its west and minor roads to its south and east, and has the small city of Bangor towards its north.

The hill originally appeared in the Hills to be surveyed sub list that accompanied the main 100m P30 list on Geoff Crowder’s v-g.me website, under the transposed name of Bangor Mountain, which is a name consistently applied on Ordnance Survey maps to land north-eastward from the summit of this hill.

 

Bangor Mountain

117m

SH579711

114/115

17/263

Trig pillar.

  

During my early hill listing I paid little regard to name placement on the map, or the meaning of names and to what feature the name was appropriately applied to.  Therefore I prioritised names for listing purposes that I now understand are either inappropriate or where another name is viewed as being more appropriate.

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

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales.

Extract from the Tithe map

The enclosed land where the summit of this hill is situated is given the number 770 on the Tithe map, this can be cross referenced against the apportionments; it is these apportionments that give the name of the owner or occupier of the land as well as the name of the land.  The land where the summit of this hill is situated is not given an individual name on the Tithe, but is confirmed as being a part of Bryniau land; Bryniau being the old farm immediately below and to the north-east of the summit, with the details on the Tithe map appearing in the parish of Bangor and in the county named as Carnarvonshire [sic].

Extract from the apportionments

After visiting the hill I took the opportunity to call at the farm of Bryniau and met James Brown; the local farmer, who was working with a colleague in one of the barns, James is aged 49 and has lived and worked the land around this farm for the last twenty years.  After explaining my interest in upland place names James accompanied me back to the summit of the hill and told me that this hill is not Mynydd Bangor (Bangor Mountain), and then gave a detailed explanation to where the land is situated that this name is applicable to.  James did not know an individual name for this hill or that of the bounded field that the summit is situated in, but told me that the hill is a part of Bryniau, which he believed would have taken its name from the hill.

James Brown; the local farmer

Therefore, the name this hill is now listed by in the 100m Twmpau is Bryniau, and this was derived from local enquiry and the details given substantiated via the Tithe map.

The full details for the hill are:

Group:  Glyder Fawr

Name:  Bryniau

Previously Listed Name:  Bangor Mountain 

  

OS 1:50,000 map:  114, 115

Summit Height:  117.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 57971 71196 (Trimble GeoXH 6000)

Bwlch Height:  86.2m (LIDAR)

Bwlch Grid Reference:  SH 57961 70836 (LIDAR) 

Drop:  31.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Myrddyn Phillips (February 2019)

Mapping Mountains – Trimble Surveys – Glyder Fawr

01.10.18  Bryniau (SH 579 711)  

Bryniau (SH 579 711)

To the immediate south-east of Bangor the small heighted ridge overlooking the city leads south-westward toward higher ground in the Glyderau.  Ordnance Survey maps give the name of Bangor Mountain to a part of this ridge, with this name consistently applied on the map to its northern part, the position of this name is also substantiated by local enquiry.  This map name would no doubt be known as Mynydd Bangor by locals. 

I’d spent the early afternoon analysing the summit and bwlch of this hill via LIDAR and now wanted to visit, it remained one of the few P30s in this part of Eryri that I had not been up and whilst doing so I hoped to meet the local farmer and make enquiries about its name.

The summit area of this hill has a golf course on its western side, with a triangulation pillar placed near to what is now the 14^th hole.  Between the trig pillar and the summit is a large covered reservoir which is well protected by high metal fencing, with the high point of the hill on the eastern side of this and close to a high mast.  As one would expect the golf course is well manicured, but between it and the summit is a mass of gorse and a double barb wired fence raised on an old stone wall.  I’d read reports of difficulty even getting to the trig from certain directions and therefore opted to approach from the north-west on a track leading toward the mast.

The well protected covered reservoir with the summit of the hill close to the high mast

I left my car on the lane that leads up toward the track and was met by a sign proclaiming ‘Private Land, no public right of way’ pinned to the access gate, I took a photograph and quietly continued up the track.

The track leads to the old farm house of Bryniau, with the summit of the hill just behind the house, foolishly I decided to bi-pass the house and follow another track on the right which led to a high and collapsed metal fence which I walked over, this led on to the golf course.

Once on the manicured fairway the view to the west opened up looking down on to the houses of Bangor, and across to Penrhos Garnedd, which I’d surveyed the day before.

I followed a perimeter path heading south, to my left was the covered reservoir with its high metalled fence and beyond was the high mast with the summit of the hill close by, and between me and it was a mass of gorse and bramble.

Although I had not planned on visiting the trig pillar the perimeter path led me toward it, I now had little option for further progress toward the summit, other than venture in to the gorse and bramble to a double barb wired fence positioned on top of a raised old wall come embankment.  As I get older I am more aware of the hazards that barb wired fences can course to a hill walker, and this one in particular was screaming out to be careful as one misplaced lunge could result in a horrible bloodied mess.

The trig pillar

I eventually landed unceremoniously on the other side of the fence and proceeded on terra firma through gaps in the gorse to the summit of the hill, which is placed on a grassy knoll under a tree.

Once the Trimble was set up I waited for it to achieve its 0.1m accuracy level before data should be logged and watched five sheep graze their way from the wooded copse behind me and onward to more juicy morsels amongst the gorse.

It took ten minutes or more for the Trimble to reach its 0.1m accuracy level, and once it did I pressed ‘Log’ and stood a few metres away from it admiring the view to the west as the sun slowly crept ever lower under an immense straight lined high cloud bank that cut across the sky.

The immense straight-lined cloud bank that quickly pushed inland as I watched from the summit of Bryniau

As the sun slowly emerged under the cloud the summit was lit with a magical glow illuminating the land.  I knew this would only last for a short time as when intense evening colour arrives it can then depart quickly, usually this lasts no more than 30 minutes or so, but it’s always a pleasure to be out on the hill at this time of day watching the play of light and bathed in its glow.

I was in no rush to leave and wanted to savour the light, away to the east the high Eryri peaks were back-dropped by grey sky and all were on display, with the Carneddau stretched out leading to the Glyderau and Tryfan squeezed in at the head of Nant Ffrancon.  I could easily of stood and stared until the last ebb of light turned the scene to dusk, but needed to get down to visit my brother in Ysbyty Gwynedd, and if time permitted to also find the local farmer at Bryniau.

The Carneddau

Yr Elen and Carnedd Llywelyn

Once the Trimble had gathered and stored 15 minutes of data I closed it down, packed it away and walked the short distance down the track to the old farm house of Bryniau, where its tenant kindly directed me to the series of old barns where James Brown; the local farmer, and a colleague were working.

The Trimble GeoXH 6000 gathering data at the summit of Bryniau

The Trimble set-up position at the summit of Bryniau

Having explained by interest in James’ hill we headed back to its summit, James explained that the hill does not have an individual name and that Mynydd Bangor is much lower on this ridge and does not apply to this hill, and that the land is a part of, and also known as Bryniau. 

James at the summit of Bryniau

As James walked the short distance back down the grassed and gorse laden upper slopes toward the track, I lingered on the summit for a last few minutes watching the sun sink in to the sea as an oranged glow emanated its surrounds.

Sunset from the summit of Bryniau

Survey Result:

Bryniau (significant name change)

Summit Height:  117.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 57971 71196 (Trimble GeoXH 6000) (summit relocation)

Bwlch Height:  86.2m (LIDAR)

Bwlch Grid Reference:  SH 57961 70836 (LIDAR)

Drop:  31.3m (Trimble GeoXH 6000 summit and LIDAR bwlch) (100m Sub-Twmpau reclassified to 100m Twmpau)

Dominance:  26.66% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble Survey Spreadsheet