Friday, 23 June 2017

Mapping Mountains – Hill Reclassifications – Y Trichant


Y Trichant – Hill Reclassifications

Y Trichant are the Welsh hills at or above 300m and below 40om in height that have a minimum drop of 30m, with these hills forming the 300m height band within the listing of the Twmpau (thirty welsh metre prominences and upward).  Accompanying the main P30 list is a sub list entitled the 300m Sub-Trichant with the qualification to 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 Introduction to this list giving its publication history appeared on Mapping Mountains on 13.05.17.

The list is authored by Myrddyn Phillips and the posts that have appeared on Mapping Mountains detailing the additions, reclassifications and deletions to the main P30 list and the sub list appear below presented chronologically in receding order.








Mapping Mountains - Hill Reclassifications - Y Trichant

Cyrnau Mawr (SN 751 750) – Sub-Trichant addition (14th reclassification)

Survey post for Cyrnau Mawr


There has been an addition to the listing of Y Trichant due to analysis of LIDAR data by Aled Williams and subsequently confirmed via a survey with the Trimble GeoXH 6000.  Y Trichant is the title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) and takes in all Welsh hills at or above 300m and below 400m in height that have a minimum 30m of drop, with the introduction to the re-naming of this list appearing on Mapping Mountains on the 13th May 2017.

The hill did not appear in the sub category that accompanied the original Welsh P30 lists when published on Geoff Crowder’s v-g.me website, this sub category has now been standardised and named the Sub-Trichant and comprises all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.

Prior to analysis of LIDAR data the hill was not classified but it was catalogued with c 16m of drop based on an estimated c 390m summit height and an estimated c 374m bwlch height, the latter height based on interpolation of bwlch contouring between 370m – 380m.

The hill is a part of the Elenydd range with its Cardinal Hill being Pen y Garn (SN 798 771) and is placed in the Region of Mid and West Wales (Region B, Sub-Region B2).  The hill is situated with the B 4574 to its north and the B 4343 to its west and is positioned between the small communities of Pontarfynach (Devil’s Bridge) to its north-west and Cwmystwyth to its east south-east. 

For those wishing to visit the summit the whole upper section of the hill is a part of designated open access land, and this has immediate access from the B 4343 to the west or from a public footpath from the same road that intersects with the open access lane.

The name of the hill is Cyrnau Mawr and its addition to Sub-Trichant status is due to the analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


Cyrnau Mawr

Summit Height:  391.4m

Summit Grid Reference:  SN 75155 75007

Bwlch Height:  369.8m

Bwlch Grid Reference:  SN 75343 74906

Drop:  21.6m


Therefore, the 391.4m LIDAR data produced for the summit position at SN 75155 75007 and the 369.8m LIDAR data produced for the bwlch position at SN 75343 74906 gives this hill 21.6m of drop which is sufficient for its inclusion as a Sub-Trichant, with the details from the Trimble GeoXH survey being 391.4m (converted to OSGM15) summit at SN 75154 75006 and 369.8m (converted to OSGM15) bwlch at SN 75342 24906, giving this hill 21.6m of drop. 



The full details for the hill are:


Cardinal Hill:  Pen y Garn

Summit Height:  391.4m (converted to OSGM15 Trimble, and LIDAR data)

Name:  Cyrnau Mawr

OS 1:50,000 map:  135, 147

Summit Grid Reference:  SN 75154 75006 
Drop:  21.6m (converted to OSGM15 Trimble, and LIDAR data)


Cyrnau Mawr (SN 751 750) confirmed as a Sub-Trichant


My thanks to Aled Williams for sending the details of this hill to me



Myrddyn Phillips (July 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant

Ffridd Fawr (SJ 166 274) – Sub-Trichant addition (13th reclassification)

Survey post for Ffridd Fawr

Significant Name Changes post for Ffridd Fawr


There has been a confirmation of an addition to the listing of Y Trichant due to a survey with the Trimble GeoXH 6000.  Y Trichant is the title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) and takes in all Welsh hills at or above 300m and below 400m in height that have a minimum 30m of drop, with the introduction to the re-naming of this list appearing on Mapping Mountains on the 13th May 2017.

The hill did not appear in the sub category that accompanied the original Welsh P30 lists when published on Geoff Crowder’s v-g.me website, this sub category has now been standardised and named the Sub-Trichant and comprises all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.

When the sub list was standardised and drop values also added the hill was listed with c 22m of drop, based on the 335m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 313m based on interpolation of bwlch contours between 310m – 320m.

The name of the hill is Ffridd Fawr which was derived from local enquiry and it is situated in the  Y Berwyn group of hills and is placed in the Region of North Wales (Region A, Sub-Region A4) with its Cardinal Hill being Craig Berwyn (SJ 071 323).  The hill is positioned above the small community of Moelfre which is to the east north-east of the hill, and between Llanrhaeadr-ym-Mochnant to the west south-west and Llansilin towards the east.  
As the hill is not a part of designated open access land, permission to visit should be sought, for those wishing to do so a public footpath approaches the hill from its north-west.

The survey with the Trimble GeoXH 6000 produced a summit height of 335.1m (converted to OSGM15) and a bwlch height of 312.4m (converted to OSGM15), with these values giving this hill 22.7m of drop, which confirms its addition to Sub-Trichant status and the total in the Y Trichant and the Twmpau will be updated accordingly.


The full details for the hill are:


Cardinal Hill:  Craig Berwyn

Summit Height:  335.1m (converted to OSGM15)

Name:  Ffridd Fawr

OS 1:50,000 map:  125

Summit Grid Reference:  SJ 16688 27439  
    
Drop:  22.7m (converted to OSGM15)


Ffridd Fawr (SJ 166 274) confirmed as an addition to the Sub-Trichant


Myrddyn Phillips (July 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant

Commins (SJ 174 282) – Sub-Trichant reclassified to Trichant (12th reclassification)

Survey post for Commins

Significant Name Changes post for Commins


There has been a confirmation of a reclassification to the listing of Y Trichant due to a survey with the Trimble GeoXH 6000.  Y Trichant is the title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) and takes in all Welsh hills at or above 300m and below 400m in height that have a minimum 30m of drop, with the introduction to the re-naming of this list appearing on Mapping Mountains on the 13th May 2017.

The hill was listed in the sub category that accompanied the original Welsh P30 lists when published on Geoff Crowder’s v-g.me website, this sub category has now been standardised and named the Sub-Trichant and comprises all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.

When the sub list was standardised and drop values also added the hill was reclassified to the main Y Trichant list with c 31m of drop which was later amended to c 34m of drop, based on the 376m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated bwlch height of c 342m based on interpolation of bwlch contours between 340m – 350m.

The name of the hill is Commins which was derived from local enquiry and it is situated in the  Y Berwyn group of hills and is placed in the Region of North Wales (Region A, Sub-Region A4) with its Cardinal Hill being Craig Berwyn (SJ 071 323).  The hill is positioned above the small communities of Moelfre which is to its east north-east and Llansilin which is farther away to the hill’s east.

As the hill is not a part of designated open access land, permission to visit should be sought, for those wishing to do so an ascent on public footpaths either from the west or east connects with green tracks which ascend toward the summit.

The survey with the Trimble produced a summit height of 376.1m (converted to OSGM15) and a bwlch height of 341.4m (converted to OSGM15), with these values giving this hill 34.7m of drop, which confirms its reclassification to Trichant status and the total in the Y Trichant and the Twmpau will be updated accordingly.


The full details for the hill are:


Cardinal Hill:  Craig Berwyn

Summit Height:  376.1m (converted to OSGM15)

Name:  Commins

OS 1:50,000 map:  125

Summit Grid Reference:  SJ 17476 28210 
  
Drop:  34.7m (converted to OSGM15)



Commins (SH 174 282) on left of photograph


Myrddyn Phillips (July 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant

Allt y Genlli (SN 985 950) – Sub-Trichant reclassified to Trichant (11th reclassification)


There has been a reclassification to the listing of the Y Trichant due to analysis of LIDAR data by Aled Williams.  Y Trichant is the title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) and takes in all Welsh hills at or above 300m and below 400m in height that have a minimum 30m of drop, with the introduction to the re-naming of this list appearing on Mapping Mountains on the 13th May 2017.

The hill was listed in the sub category that accompanied the original Welsh P30 lists when published on Geoff Crowder’s v-g.me website, this sub category has now been standardised and named the Sub-Trichant and comprises all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.

Prior to analysis of LIDAR data the hill was listed as a Sub-Trichant and its reclassification is dependent upon its adjacent southerly hill of Mynydd Garth Pwt, because of this the previously listed details of both hills based on map data are given below: 



Allt y Genlli (previously listed as a Sub-Trichant)

Summit Height:  394m (OS 1:25,000 Explorer map)

Summit Grid Reference:  SN 985 950

Bwlch Height:  367m (OS enlarged mapping hosted on the Geograph website)

Bwlch Grid Reference:  SN 983 944

Drop:  27m




Mynydd Garth Pwt (listed as a Trichant)

Summit Height:  397m (OS 1:50,000 Landranger and 1:25,000 Explorer maps)

Summit Grid Reference:  SN 981 941

Bwlch Height:  c 325m

Bwlch Grid Reference:  SN 973 941

Drop:  c 72m



The hill is a part of the Pumlumon range of hills with its Cardinal Hill being Bryn Amlwg (SN 921 973) and is placed in the Region of Mid and West Wales (Region B, Sub-Region B2).  The hill is situated to the south of the A 470 and is positioned between the small communities of Carno to its west north-west and Clatter to its east.

The upper part of the hill is a part of designated open access land, however it is also immersed in conifer plantation with its summit encircled by a forest track, and for those who wish to visit its high point an approach from the north using this track may be the best option.

The name of the hill is Allt y Genlli and its reclassification from Sub-Trichant to Trichant status is dependent upon its adjacent southerly hill of Mynydd Garth Pwt and the analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

Aled’s analysis of LIDAR data gives these two hills the following details:


Allt y Genlli

Summit Height:  398.9m

Summit Grid Reference:  SN 98508 95042

Bwlch Height:  325.7m

Bwlch Grid Reference:  SN 97387 94159

Drop:  73.2m




Mynydd Garth Pwt

Summit Height:  397.8m

Summit Grid Reference:  SN 98154 94173

Bwlch Height:  367.3m

Bwlch Grid Reference:  SN 98385 94438

Drop:  30.5m


Therefore, as the 398.9m LIDAR data produced for the summit position of Allt y Genlli at SN 98508 95042 is higher than the 397.8m LIDAR data produced for the summit position of Mynydd Garth Pwt at SN 98154 94173, the listed bwlch position of each hill is swapped as the lower bwlch is the critical bwlch for the higher of the two hills.


The full details for the two hills are:


Cardinal Hill:  Bryn Amlwg

Summit Height:  398.9m (LIDAR data)

Name:  Allt y Genlli

OS 1:50,000 map:  136

Summit Grid Reference:  SN 98508 95042  

Drop:  73.2m (LIDAR data)




Cardinal Hill:  Bryn Amlwg

Summit Height:  397.8m (LIDAR data)

Name:  Mynydd Garth Pwt

OS 1:50,000 map:  136

Summit Grid Reference:  SN 98154 94173  

Drop:  30.5m (LIDAR data)



My thanks to Aled Williams for sending the details of this hill to me.


Myrddyn Phillips (May 2017)







Mapping Mountains - Hill Reclassifications - Y Trichant

Penmaen Mawr (SH 702 756) – Sub-Trichant reclassified to Trichant (10th reclassification)


There has been a reclassification to the listing of the Y Trichant, this is the draft title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) due to analysis of LIDAR data by Aled Williams.  The hill was previously surveyed with the Trimble GeoXH 6000 and included as a Sub-Trichant with 29.8m of drop.  The criteria for Y Trichant being all Welsh hills 300m or more and below 400m in height with 30m minimum drop and the Sub-Trichant being all Welsh hills 300m or more and below 400m in height with 20m or more and below 30m of drop.

The hill was not classified prior to the survey with the Trimble as much of the hill has been quarried and as is the norm in such circumstances there is a lack of uppermost contour lines on current Ordnance Survey maps.  But at one stage it was a part of a relatively substantial hill that had a prominence in excess of 100m and a 1,550ft (472m) summit map height shown on the Ordnance Survey Popular and New Popular One-Inch maps, with this height also appearing on the Ordnance Survey Six-Inch map published in 1888, and therefore it would have met the criteria specified for inclusion to the Humps and the Y Pedwarau listings.  The subsequent quarrying has produced two distinct summits with the details given in this post relating to the lower of the two summits that are both known by the same name.

The hill is a part of the Carneddau range with its Cardinal Hill being Tal y Fan (SH 729 726) and is placed in the Region of North Wales (Region A, Sub-Region A1).  The hill is situated to the south of the A 55 and is positioned between the towns of Llanfairfechan to its west and Penmaenmawr to its east, with the latter taking its name from the hill.  

The hill can be easily accessed from a minor road to the south of the summit that reaches over 260m in height, a public footpath heads north from just below the high point of this minor road and joins a track which is marked as a bridleway that contours around the southern slopes of the upper section of the hill.  A large section of land above the bridleway is designated open access and the summit of the lower of the two Penmaen Mawr hills is close to this.

The name of the hill is Penmaen Mawr and its reclassification from Sub-Trichant to Trichant status is due to analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


Penmaen Mawr

Summit Height:  385.8m

Summit Grid Reference:  SH 70292 75649

Bwlch Height:  354.5m

Bwlch Grid Reference:  SH 70441 75241

Drop:  31.3m


Therefore, the 385.8m LIDAR data produced for the summit position at SH 70292 75649 and the 354.5m LIDAR data produced for the bwlch position at SH 70441 75241 gives this hill 31.3m of drop, which is sufficient for its reclassification to a Trichant, therefore the total in the Y Trichant and the Twmpau which will be updated accordingly.


The full details for the hill are:

Cardinal Hill:  Tal y Fan

Summit Height:  385.8m (LIDAR data)

Name:  Penmaen Mawr

OS 1:50,000 map:  115

Summit Grid Reference:  SH 70292 75649  

Drop:  31.3m (LIDAR data)



Penmaen Mawr (SH 702 756) now reclassified from a Sub-Trichant to a Trichant

My thanks to Aled Williams for sending the details of this hill to me.


Myrddyn Phillips (May 2017)







Mapping Mountains - Hill Reclassifications - Y Trichant

Twyn y Ffald (SN 852 160) - Sub-Trichant addition (9th reclassification)


There has been an addition to the listing of the Y Trichant, this is the draft title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) due to analysis of LIDAR data by Aled Williams.  With the criteria for Y Trichant being all Welsh hills 300m or more and below 400m in height with 30m minimum drop.

Accompanying the main Y Trichant list is a sub list entitled the Sub-Trichant.  With the criteria for Sub-Trichant qualification being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.

Prior to analysis of LIDAR data the hill was catalogued with c 19m of drop which was insufficient for it to be listed as a Sub-Trichant, this drop value was based on an estimated summit height of c 362m and an estimated bwlch height of c 343m, with the latter taken to land that forms a part of a disused quarry, and therefore the old connecting bwlch of this hill no longer exists.

The hill is adjoined to the Fforest Fawr group of hills with its Cardinal Hill being Fan Gyhirych (SN 880 191) and is placed in the Region of South Wales (Region C, Sub-Region C2), and is situated with the small community of Glyntawe to its north-west.

The hill can be accessed from the end of a minor road at Penwyllt and can be combined with higher hills to its east.  However, the summit of this hill is not on open access land and it is positioned on the periphery of a disused quarry, therefore permission should be sought to visit, but with open access land relatively close towards the north-east, common sense should prevail and if wanting to visit the summit there is likely to be no objection to doing so.

The name of the hill is Twyn y Ffald and its addition to Sub-Trichant status is due to analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


Twyn y Ffald

Summit Height:  368.7m

Summit Grid Reference:  SN 85227 16034

Bwlch Height:  342.8m

Bwlch Grid Reference:  SN 85541 16188

Drop:  25.9m


Therefore, the 368.7m LIDAR data produced for the summit position at SN 85227 16034 and the 342.8m LIDAR data produced for the bwlch position at SN 85541 16188 gives this hill 25.9m of drop, which is sufficient for its inclusion as a Sub-Trichant, therefore this hill is included in this sub category and the total in the Y Trichant and the Twmpau which will be updated accordingly.


The full details for the hill are:

Cardinal Hill:  Fan Gyhirych

Summit Height:  368.7m (LIDAR data)

Name:  Twyn y Ffald

OS 1:50,000 map:  160

Summit Grid Reference:  SN 85227 16034
   
Drop:  25.9m (LIDAR data)



My thanks to Aled Williams for sending the details of this hill to me.


Myrddyn Phillips (April 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant

Pt. 360.1m (SH 700 466) - Sub-Trichant addition (8th reclassification)


There has been an addition to the listing of Y Trichant, this is the draft title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) due to analysis of LIDAR data by Aled Williams.  The criteria for Y Trichant being all Welsh hills 300m or more and below 400m in height with 30m minimum drop and the now standardised Sub-Trichant being all Welsh hills 300m or more and below 400m in height with 20m or more and below 30m of drop, with this hill being an addition to the Sub-Trichant category.

The hill is a contentious addition to the Sub-Trichant as it is a part of the Llechwedd Slate Mine and may be viewed by some as not being stable in nature and is described as a Tip (disused) on the Ordnance Survey enlarged mapping hosted on the Geograph website.  As is the norm with such places it is not given any ring contours on current Ordnance Survey maps.

The hill is adjoined to the Arenig group with its Cardinal Hill being Manod Mawr (SH 724 446) and is placed in the Region of North Wales (Region A, Sub-Region A3), and it is situated above the town of Blaenau Ffestiniog which is to its south and has the A 470 road to its west.

As this hill is a part of a slate mine that is worked intermittently permission to visit should be sought, because of this no route to its summit is recommended.

The Point (Pt. 360.1m) notation is being used as I do not know an appropriate local or historical name for this hill, and its addition as a Sub-Trichant is due to analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


Pt. 360.1m

Summit Height:  360.1m

Summit Grid Reference:  SH 70068 46618

Bwlch Height:  332.1m

Bwlch Grid Reference:  SH 70214 46655

Drop:  28.0m


Therefore, the 360.1m LIDAR data produced for the summit position at SH 70068 46618 and the 332.1m LIDAR data produced for the bwlch position at SH 70214 46655 gives this hill 28.0m of drop, which is sufficient for its inclusion as a Sub-Trichant, and the listings of Y Trichant and the Twmpau which will be updated accordingly.


The full details for the hill are:

Cardinal Hill:  Manod Mawr

Summit Height:  360.1m (LIDAR data)

Name:  Pt. 360.1m

OS 1:50,000 map:  115

Summit Grid Reference:  SH 70068 46618 
  
Drop:  28.0m (LIDAR data)


Pt. 360.1m (SH 700 466) a new addition to the Sub-Trichant

My thanks to Aled Williams for sending the details of this hill to me.


Myrddyn Phillips (April 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant

Garreg Ddu (SH 701 462) - Trichant reclassified to Sub-Trichant (7th reclassification)


There has been a reclassification to the listing of Y Trichant, this is the draft title for the hills in the 300m height band of the Twmpau (thirty welsh metre prominences and upward) due to analysis of LIDAR data by Aled Williams.  The hill was listed in the sub category that accompanied the original Welsh P30 lists when published on Geoff Crowder’s v-g.me website, with the criteria for Y Trichant being all Welsh hills 300m or more and below 400m in height with 30m minimum drop and the now standardised Sub-Trichant being all Welsh hills 300m or more and below 400m in height with 20m or more and below 30m of drop.

When drop values were added to the Welsh P30 Master Lists this hill was given an estimated c 29m of drop, however this was re-evaluated and the hill was reclassified to Trichant status with c 30m of drop, this was based on the 348m summit spot height that appears on Ordnance Survey 1:25,000 Explorer maps and an estimated bwlch height of c 318m.  

The hill is adjoined to the Arenig group of hills with its Cardinal Hill being Manod Mawr (SH 724 446) and is placed in the Region of North Wales (Region A, Sub-Region A3).  The hill is situated between the town of Blaenau Ffestiniog to its immediate south and the Llechwedd Slate Mines to its immediate north.

The hill forms the southern barrier to the extensive slate mines that pre-dominate the landscape above and to the north of Blaenau Ffestiniog, and is situated on open access land, and can be accessed from the backstreets of the town leading to an old incline to the open hillside above.

The name of the hill is Garreg Ddu and its reclassification to Sub-Trichant status is due to analysis of LIDAR data by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


Garreg Ddu

Summit Height:  348.0m

Summit Grid Reference:  SH 70186 46223

Bwlch Height:  319.6m

Bwlch Grid Reference:  SH 70178 46356

Drop:  28.4m


Therefore, the 348.0m LIDAR data produced for the summit position at SH 70186 46223 and the 319.6m LIDAR data produced for the bwlch position at SH 70178 46356 gives this hill 28.4m of drop, which is insufficient for its retention as a Trichant, therefore this hill is listed as a Sub-Trichant and the total in the Y Trichant and the Twmpau which will be updated accordingly.


The full details for the hill are:

Cardinal Hill:  Manod Mawr

Summit Height:  348.0m (LIDAR data)

Name:  Garreg Ddu

OS 1:50,000 map:  115

Summit Grid Reference:  SH 70186 46223 
  
Drop:  28.4m (LIDAR data)


Garreg Ddu (SH 701 462) now reclassified to a Sub-Trichant

My thanks to Aled Williams for sending the details of this hill to me.

Myrddyn Phillips (April 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant


MRF Tip (SN 828 114) - Trichant addition (6th reclassification)

There has been an addition to the listing of the Y Trichant, these are the hills within the 300m height band of the Twmpau (thirty welsh metre prominences and upward) due to analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams.  The Y Trichant takes in all hills in Wales at or above 300m and below 400m in height that have a minimum drop of 30m.

Prior to analysis of LIDAR data the ridge known as Mynydd y Drum was listed with one summit, but due to opencast mining a further two summits have been created which are artificial and comprise the remains of waste spoil, the summit which this Hill Reclassifications post details is the lower of these two artificial hills, this has resulted in new bylchau heights and positions and also drop values for these three hills, all of these will be detailed in this and the previous and next Hill Reclassifications posts, with the name MRF Tip being found from local enquiry and the other two hills being Mynydd y Drum (SN 807 097) and Teisen Priodas (SN 820 108).

The hill is adjoined to the Fforest Fawr group with its Cardinal Hill being Fan Gyhirych (SN 880 191) and is placed in the Region of South Wales (Region C, Sub-Region C2), and it is positioned between the small communities of Abercraf (Abercrave) to the north-west and Y Coelbren towards the east.

The summit of the hill is situated within the Nant Helen Opencast Mine so permission to visit the high point should be sought, however it has open access land to its east and a little farther away to its south, and two public footpaths are marked on Ordnance Survey maps that head extremely close to the summit of this hill.

The name of the hill is MRF Tip and its reclassification to a Trichant is due to the analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


MRF Tip

Summit Height:  311.8m (converted to OSGM15)

Summit Grid Reference:  SN 82850 11432

Bwlch Height:  277.6m (converted to OSGM15)

Bwlch Grid Reference:  SN 82186 11128

Drop:  34.2m


Therefore, the 311.8m LIDAR data produced for the summit position at SN 82850 11432 and the 277.6m LIDAR data produced for the bwlch position at SN 82186 11128 is sufficient for this hill to be classified as a Trichant with 34.2m of drop.

This now revises the total in the Y Trichant and the Twmpau and the lists will be updated accordingly.


The full details for the hill are:

Cardinal Hill:  Fan Gyhirych

Summit Height:  311.8m (LIDAR data, converted to OSGM15)

Name:  MRF Tip

OS 1:50,000 map:  160

Summit Grid Reference:  SN 82850 11432
   
Drop:  34.2m (LIDAR data, converted to OSGM15)


MRF Tip (SN 828 114) now listed as a Trichant

My thanks to Mark Jackson for bringing the details of this hill to my attention and to Kevin McGovern and Aled Williams for their analysis of LIDAR data.


Myrddyn Phillips (March 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant


Teisen Priodas (SN 820 108) - Trichant addition (5th reclassification)

Survey post for Teisen Priodas

Significant Name Changes post for Teisen Priodas

Significant Height Revisions post for Teisen Priodas


There has been an addition to the listing of the Y Trichant, these are the hills within the 300m height band of the Twmpau (thirty welsh metre prominences and upward) due to analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams, and subsequently confirmed via a survey with the Trimble GeoXH 6000.  With the high point of the hill previously listed in the 200m height band when the Welsh P30 hills below 500m in height were published on Geoff Crowder’s v-g.me website.

The hill had been listed with a 297m summit height positioned at SN 807 098 based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map numbers 12 and 165, whilst the Ordnance Survey 1:50,000 Landranger map number 160 gives a 298m summit spot height at the same position.  This latter spot height is derived from the 978.1ft (298.1ft) height on the Ordnance Survey old Six-Inch map.

When this hill was originally listed in the Welsh P30 lists on the v-g.me website it had an accompanying note which stated ‘3 points of 300m on 1985 map may probably no longer exist (quarrying)’.  The hand written Master Lists stated ‘Due to opencast workings the three points of 300c at GR 830 112 on 1985 1:50,000 map probably no longer exist’.  These three points are in the vicinity of where a 984ft (299.9m) height appears on the Ordnance Survey old Six Inch map and in all likelihood signified where the summit of this hill was once positioned.  Since this time the Nant Helen Openacast Mine workings which take in the northern and eastern part of the ridge known as Mynydd y Drum have destroyed the old 984ft (299.9m) summit, but in its place are two new P30 summits comprising the spoil from the mine workings, with this Hill Reclassifications post concentrating on the higher of these two artificial summits, whilst the 296.2m (converted to OSGM15) natural summit at SN 80718 09753 and listed as Mynydd y Drum still remains. 
  
Prior to analysis of LIDAR data the ridge known as Mynydd y Drum was listed with one summit, the opencast mine has now created a further two summits which are artificial and comprise the remains of waste spoil, the summit which this Hill Reclassifications post details is now higher than the previously listed summit, resulting in new bylchau heights and positions and also drop values for these three hills, all of these will be detailed in this and two further Hill Reclassifications posts, with the name Teisen Priodas being found from local enquiry and the other two hills being Mynydd y Drum (SN 807 097) and MRF Tip (SN 828 114).

The hill is adjoined to the Fforest Fawr group with its Cardinal Hill being Fan Gyhirych (SN 880 191) and is placed in the Region of South Wales (Region C, Sub-Region C2), and it is positioned between the small communities of Abercraf (Abercrave) to the north and Y Coelbren towards the east.

The summit of the hill is situated within the Nant Helen Opencast Mine so permission to visit the high point should be sought, however it has open access land to its south-west and a public footpath marked on Ordnance Survey maps that heads in a north- south direction and at its closest point is just to the west of the summit of this hill.

The name of the hill is Teisen Priodas and its reclassification to a Trichant is due to the analysis of LIDAR data by Kevin McGovern and also independently by Aled Williams.  LIDAR (Light Detection & Ranging) is highly accurate height data that is now freely available for much of England and Wales.

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


Teisen Priodas

Summit Height:  338.2m (converted to OSGM15)

Summit Grid Reference:  SN 82014 10832

Bwlch Height:  244.8m (converted to OSGM15)

Bwlch Grid Reference:  SN 84566 11384

Drop:  93.4m


Therefore, the 338.2m LIDAR data produced for the summit position at SN 82014 10832 and the 244.8m LIDAR data produced for the bwlch position at SN 84566 11384 is sufficient for this hill to be classified as a Trichant with 93.4m of drop and for it to be listed with a higher summit than the 296.2m (converted to OSGM15) summit of Mynydd y Drum at SN 80718 09753, with the details from the Trimble GeoXH 6000 survey being 337.9m (converted to OSGM15) summit at SN 82013 10833 and 244.6m (converted to OSGM15) bwlch at SN 84569 11383, giving this hill 93.3m of drop.

This now revises the total in the Y Trichant and the Twmpau which will be updated accordingly.


The full details for the hill are:

Cardinal Hill:  Fan Gyhirych

Summit Height:  337.9m (converted to OSGM15, Trimble data)

Name:  Teisen Priodas

OS 1:50,000 map:  160

Summit Grid Reference:  SN 82013 10833 
  
Drop:  93.3m (converted to OSGM15, Trimble data)


Teisen Priodas (SN 820 108) a new addition to the Y Trichant list

My thanks to Mark Jackson for bringing the details of this hill to my attention and to Kevin McGovern and Aled Williams for their analysis of LIDAR data.


Myrddyn Phillips (March 2017)






Mapping Mountains - Hill Reclassifications - Y Trichant

Penmaen Mawr (SH 702 757) - Sub-Trichant addition (4th reclassification)

Survey post for Penmaen Mawr


THIS HILL HAS SUBSEQUENTLY BEEN RECLASSIFIED FROM A SUB-TRICHANT TO A TRICHANT

The following details have been superseded by analysis of LIDAR data by Aled Williams with the result that this hill has been reclassified from a Sub-Trichant to a Trichant as LIDAR data gives the hill 31.3m of drop.  The Y Trichant are the Welsh P30 hills in the 300m height band of the Twmpau.

The below is the Hill Reclassifications post prior to LIDAR data analysis:


There has been a promotion to the listing of Twmpau (thirty welsh metre prominences and upward) hills due to a recent survey with the Trimble GeoXH 6000.  The hill is now listed in the Sub-List adjoined to the 300m height band of Twmpau hills and is situated in the northern Carneddau in north-west Wales.

The hill was not classified prior to the survey with the Trimble as the majority of the summit has been quarried and there is a lack of uppermost contour lines on current Ordnance Survey maps.  But at one stage it was a part of a relatively substantial hill that had a prominence in excess of 100m and a 1,550ft (472m) summit map height on the Ordnance Survey Popular and New Popular One-Inch maps, with this height also appearing on the Ordnance Survey Six-Inch map published in 1888, and therefore it would have met the criteria specified for inclusion to the Humps and the Y Pedwarau listings.

Because of this the hill did not appear in the Sub-List which accompanied the original Welsh P30 listings on Geoff Crowder’s v-g.me website as the Sub-List only included hills whose map details showed that when surveyed they may stand a chance of qualification to the main P30 list, with the title of the Sub-List being ‘Hills to be surveyed.’  And as this hill only has an uppermost 350m contour line in the vicinity of its summit area and also bwlch, map detail intimated that there was insufficient drop for inclusion to this Sub-List.  However, since first publication this Sub-List has been standardised and now includes all hills that have a minimum of 20m of drop and below 30m of drop.

The hill is situated to the south of the A 55 and is positioned between the towns of Llanfairfechan to its west and Penmaenmawr to its east, with the latter taking its name from the hill.  The quarrying of this hill has now left two distinct summits, the higher western summit and the lower easterly summit which this post details.   

The hill can be easily accessed from a minor road to the south of the summit that reaches over 260m in height, a public footpath heads north from just below the high point of this minor road and joins a bridlewayed track that contours around the southern slopes of the upper section of the hill.  A large section of the land above the bridleway is open access and the summit Penmaen Mawr is close to this.

The survey with the Trimble GeoXH 6000 resulted in a 384.9m (converted to OSGM15) summit height and a 355.1m (converted to OSGM15) bwlch height, giving this hill 29.8m of drop and therefore it qualifies as a 300m Sub-Twmpau.


The full details for the hill are:

Cardinal Hill:  Carnedd Llywelyn

Summit Height:  384.9m (converted to OSGM15)

Name:  Penmaen Mawr

OS 1:50,000 map:  115

Summit Grid Reference:  SH 70200 75727  

Drop:  29.8m (converted to OSGM15)


Penmaen Mawr (SH 702 757) now classified as a 300m Sub-Twmpau



Myrddyn Phillips (August 2016)







Mapping Mountains - Hill Reclassifications - Y Trichant

Moel y Gôd (SJ 072 168) - 300m Twmpau addition (3rd reclassification)

Survey post for Moel y Gôd
  

There has been a new addition to the 300m Twmpau (thirty welsh metre prominences and upward) hill list with its confirmation as a P30 instigated by a survey with the Trimble.   The hill is situated between Llanwddyn to its west, Dolanog to its south, Llanfyllin to its east and Pen-y-bont-fawr to its north, and is positioned in the central part of the Y Berwyn.

The hill is named Moel y Gôd and the first time it ever appeared in a hill list was in 2003 when the original Welsh P30 hills under 500m in height were published on Geoff Crowder’s v-g.me website.  It was then listed in the Sub-List which was named ‘Hills to Survey’.  The reason for this was that Moel y Gôd was only given a 308m summit spot height on current maps, and meant that its qualification to the main P30 list was dependent upon bwlch contour interpolation.  As the use of interpolation did not form part of this list the hill was listed in the ‘Hills to Survey’ Sub-List.   When this list was first published on Geoff’s website it did not include a drop value for each hill, although the qualification for the main list and the Sub-List was based on drop, these values were added to the list at a later date.

When these drop values were added I also decided to include hills in the Main P30 Twmpau list through interpolation of map contours, although some of these details were passed onto Geoff, the great majority were not.  When these figures were added to the list I gave Moel y Gôd c 35m of drop and promoted it into the ranks of P30 hills.  This drop value was estimated from its 308m summit spot height and an estimated bwlch height of c 273m based on the 1:25,000 map bwlch contouring between 270m – 280m.  Even though the hill had been promoted in my list the details were never made public, so it was now time to have it Trimbled and to confirm its status via the Mapping Mountains site.

The hill can be accessed from where a public footpath contours round its northern flank; however the summit is not situated on open access land so permission to visit should be sought.  There is sufficient parking for one or two vehicles near the intersection between the B 4393 and the B 4395 which is only a short distance from the gate giving access on to the footpath.

The survey with the Trimble GeoXH 6000 resulted in a 307.6m (converted to OSGM15) summit height and a 270.6m (converted to OSGM15) bwlch height; these values give this hill 37.0m of drop and confirm its status as a P30 Twmpau.


The full details for the hill are:

Cardinal Hill:  Rhialgwm

Summit Height:  307.6m (converted to OSGM15)

Name:  Moel y Gôd

OS 1:50,000 map:  125

Summit Grid Reference:  SJ 07248 16808

Drop:  37.0m (converted to OSGM15)


Moel y Gôd (SJ 07248 16808) now confirmed as a 300m Twmpau

For details on the survey that confirmed this hill as a 300m Twmpau status please click {here}

Myrddyn Phillips (May 2016)







Mapping Mountains - Hill Reclassifications - Y Trichant

Pen y Gaer (SO 139 976) - 200m Twmpau reclassified to 300m Twmpau (2nd reclassification)

Survey post for Pen y Gaer


There has been a new addition to the 300m Twmpau list due to a survey with the Trimble GeoXH 6000.  The evidence for the promotion of this hill is marginal, but until more accurate information is at hand the hill has been reclassified from the ranks of the 200m Twmpau to that of the 300m Twmpau list.


The raw processed survey result is 300.002m converted to OSGM15

The margin of uncertainty for the height in relation to the position of the Trimble on the summit is 0.05m.

The precision of the equipment is +/- 0.15m.

The accuracy of the equipment is 0.1m.

Therefore the raw result should be rounded to one decimal place; 300.0m


The name of the hill is Pen y Gaer (SO 139 976) and it is situated in the Carnedd Wen range of hills and is positioned between the small communities of Betws Cedewain and Pentrellifior.


The full details for the hill are:

Cardinal Hill:  Carnedd Wen

Summit Height:  300.0m (converted to OSGM15)

Name:  Pen y Gaer

OS 1:50,000 map:  136

Summit Grid Reference:  SO 139 976

Drop:  88m


Pen y Gaer (SO 139 976) the new 300m Twmpau
For details on the survey that reclassified this hill to 300m Twmpau status please click {here}


Myrddyn Phillips (January 2015)







Mapping Mountains - Hill Reclassifications - Y Trichant

Mynydd Derw Llwydion (SO 907 900) - 300m Sub-Twmpau reclassified to 300m Twmpau (1st reclassification)

Survey post for Mynydd Derw Llwydion


There has been a new addition to the 300m Twmpau list due to a recent survey with the Trimble GeoXH 6000.  The hill sneaks in with 14 millimetres to spare!  This margin is within the uncertainty applied to the equipment and its positioning at the summit and the bwlch.  However, reclassifications are taking place in the listings I have compiled and those jointly done with Aled Williams, from best available evidence on the day and as this hill used to be listed with 29m of drop based on Ordnance Survey summit and bwlch spot heights, the Trimble data will be more accurate.  So until better evidence is produced the hill is promoted from the 300m Sub-Twmpau list and becomes a new P30.  The hill is situated in the Pumlumon range amongst many P30s between Llyn Clywedog and Penffordd-las (Staylittle).


The full details for the hill are:


Cardinal Hill:  Foel Fadian

Summit Height:  388.1m (converted to OSGM15)

Name:  Mynydd Derw Llwydion

OS 1:50,000 map:  136

Summit Grid Reference:  SN 90721 90069

Drop:  30.0m (converted to OSGM15)


The Trimble GeoXH 6000 on the summit of Mynydd Derw Llwydion, which is now reclassified to a 300m Twmpau

For details on the survey that reclassified this hill to 300m Twmpau status please click {here}


Myrddyn Phillips (April 2014)


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