Wednesday 11 December 2013

Hill Reclassifications - 200m Twmpau List


This part of the Mapping Mountains blog is dedicated to any hill reclassification for the listings I have compiled.  These include ones found from map detail as well as those from accurate surveying.

There have been a number of recent new entries to the Welsh 200m P30 list that have not appeared in published format, including some that do not appear on other P30 listings, these are:


Carneddau            Y Pincin    264m    SH 723 581
This is a lovely small rocky hill that overlooks Capel Curig and can be joined with an ascent of Crimpiau (SH 732 595) and the higher hills to the north.  Its bwlch is at SH 724 581 and is estimated as c 228m, giving c 36m of drop.

To see the results of a Trimble survey of this hill click {here} and {here}


Moel Hebog            Moel Isallt    286m    SH 537 445
Another hill that was always a prime candidate for promotion from the sub-list and with the large scale Ordnance Survey mapping on the Geograph website giving a 252m spot height on the area of the bwlch it gives this hill 34m of drop.


Moel Hebog            Moelfryn    277m    SH 568 511
With a summit height of 277m and bwlch contouring between c 240m – c 250m, with the hill to hill contouring being relatively close when compared to the valley to valley contouring, this hill was always a prime candidate for promotion from the sub-list and with an estimated bwlch height of c 247m, it enters the list with c 30m of drop.


Pen Llลทn            Moel Caerau    207m    SH 292 354
This hill was always a prime candidate for promotion from the sub-list and with the large scale Ordnance Survey mapping on the Geograph website giving a 173m spot height on the area of the bwlch it gives this hill 34m of drop. 


Moelwynion            Cefn Bychan    c 244m    SH 695 454  
The uppermost ring contour on current maps is c 240m with the bwlch positioned at an estimated SH 698 458.  Bwlch contouring on current maps is between c 210m – c 220m and suggests a height of c 212m – c 213m.

The Ordnance Survey Historical 1:25,000 map on the Sabre Maps website gives an uppermost contour of 800ft (243.8m) and a lowest continuous contour encircling the hill of 700ft (213.4m).  This lower contour is dotted implying the area has been extensively altered.  Current maps imply the critical bwlch to be at the junction of Towyn Road and Dorvil Road in Blaenau Ffestiniog.  The Ordnance Survey 1:2500 map from 1977 on the Old Maps website gives a levelled height of 212.1m positioned at this road junction.

The best available evidence suggests the height of Cefn Bychan is c 244m and its bwlch is 212m, giving c 32m of drop. 


Arennig            Bryn-coch    293m    SH 873 325
This hill has been promoted from the sub-list as the bwlch contouring suggests a critical bwlch height of c 263m, giving this hill c 30m of drop. 


Arennig            Coed Glanllyn    249m    SH 884 321
The listed name of this hill has been altered from Pen Coed Glanllyn to Coed Glanllyn as the ‘Pen’ part of the name was invented and unnecessary, the name of Bryniau appears on current Ordnance Survey maps and has been used in other P30 listings, but map study implies this name relates to the buildings at SH 884 324 and not to the hill itself.  This hill has been promoted from the sub-list as the large scale Ordnance Survey mapping on the Geograph website gives a 249m spot height on the area of the summit.  The bwlch contouring suggests a critical bwlch height of c 219m at SH 881 323, giving c 30m of drop. 


Arennig            Pt. 245m    245m    SH 997 438
This hill used to be listed in the sub-list with c 28m of drop under the name of Carreg-y-big.  The drop value was estimated from bwlch contouring between c 210m – c 220m.  The Pt. notation has now been used for its name as mapping suggests that the name Carreg-y-big applies to the building situated at SH 998 438 and not directly to the hill itself.  However, many farm buildings are named after ‘their’ hill and this may be the case here, but until further investigation the name converts to the Pt. notation.

The large scale Ordnance Survey mapping on the Geograph website gives a 215m spot height on the area of the bwlch.  Although the valley to valley traverse is relatively expansive the spot height appears in the approximate position where interpolation suggests the critical bwlch is placed.  Its 215m bwlch is at SH 994 434, giving 30m of drop. 


Arennig            Pen y Foel    214m    SH 661 395
Another hill promoted from the sub-list as the large scale Ordnance Survey mapping on the Geograph website gives a 214m spot height on the area of the summit.  The only other height to have appeared for this hill is 212m on the Ordnance Survey 1:50,000 map, this matches the old imperial height of 696ft.

The bwlch contouring is between c 180m – c 190m with the valley to valley contours closer than the hill to hill contours, implying a bwlch height of c 184m.  It is hoped to accurately survey this hill in the future for P30 confirmation, but for now it enters the Welsh 200m P30 list.

This hill is listed with a summit height of 214m and a bwlch height of c 184m, giving c 30m of drop.





There have also been a number of ‘new’ subs that have entered the Welsh 200m P30 listing, these are:

Carneddau            Pt. 248m    248m    SH 784 580
This is a forested summit to the north-west of Betws-y-coed.  Dependent upon the density of the conifers this hill may be a good candidate to survey with the Trimble for P30 status as it is listed with c 29m of drop.


Carneddau            Pt. c. 236m    c 236m    SH 750 777
The summit of this hill appears where the 5m contour intervals revert to 10m contour intervals on the large scale Ordnance Survey mapping on the Geograph website.  However, the uppermost c 235m contour is evident and the summit has been estimated as c 236m.  The height of the bwlch has been estimated as c 213m, giving c 23m of drop.


Carneddau            Pt. 253m    253m    SH 788 583
This is another forested summit to the north of Betws-y-coed.  It has an estimated bwlch height of c 232m, giving c 21m of drop.


Moel Hebog            Bryn Cwellyn    c 272m    SH 564 536
A forested summit near to Llyn-y-forwyn which has an estimated summit height of c 272m (a separate point at SH 56454 53329 is estimated as c 271m) and an estimated height at Bwlch y Moch (SH 561 540) of c 252m, giving a drop of c 20m.


Moel Hebog            Craig Isallt    233m    SH 532 449
With a summit height of 233m and an estimated bwlch height of c 213m, this hill just makes it in to the sub-list with c 20m of drop.


Moelwynion            Pt. 294m    294m    SH 727 533
With a summit spot height of 294m and a bwlch spot height of 268m, this hill has 26m of drop.


Moelwynion            Pt. 248m    248m    SH 671 424
This hill has a height of 248m on the large scale Ordnance Survey mapping on the Geograph website and it has two options for its critical bwlch, they are positioned at SH 667 424 and SH 673 425, both are estimated to be c 223m, giving this hill c 25m of drop.


Moelwynion            Pt. c 281m    c 281m    SH 776 549
Another forested summit with both summit and bwlch height being estimated from contour interpolation, with the bwlch estimated as c 259m at SH 775 550, giving this hill c 22m of drop.


Moelwynion            Y Foel    288m    SH 799 503
The bwlch is positioned between c 260m – c 270m contours and is estimated as c 267m at SH 802 503.  This gives the hill c 21m of drop.


Moelwynion            Pt. 257m    257m    SH 785 556
There are two options for this hill’s critical bwlch, they are positioned at SH 785 553 and SH 787 551, both are estimated to be c 236m, giving this hill c 21m of drop.


Moelwynion            Pt. c 274m    c 274m    SH 696 518
Another forested summit with both summit and bwlch height being estimated from contour interpolation, with the bwlch estimated as c 254m at SH 695 519, giving this hill c 20m of drop.


Moelwynion            Clogwyn Mawr    269m    SH 699 519
Looks like a good rocky summit clear of forest, although the majority of the hill is within conifer plantation.  The bwlch is positioned at SH 697 518 and has been estimated as c 249m, giving c 20m of drop.


Moelwynion            Pt. 263m    263m    SH 626 484
With a height of 263m on the large scale Ordnance Survey mapping on the Geograph website and an estimated bwlch height of c 243m which is positioned at SH 625 484, this hill has c 20m of drop.  The same enlarged mapping gives a 241m spot height on the area of the bwlch at SH 625 485, although this may be the position and height of the critical bwlch, contouring suggests otherwise.


Moelwynion            Pt. 256m    c 256m    SH 784 549
A forested summit near to Llyn Elsi which has a height of 256m on the large scale Ordnance Survey mapping on the Geograph website, the bwlch is positioned at SH 787 551 and is estimated as c 236m, giving c 20m of drop. 


Moelwynion            Pt. 229m    229m    SH 621 459
With a height of 229m on the large scale Ordnance Survey mapping on the Geograph website and a bwlch positioned at SH 621 459 with an estimated height of c 209m, this hill has c 20m of drop.


Rhinogydd            Pt. 215m    215m    SH 637 314
This hill is positioned just above the southern part of Llyn Cwm Bychan and has a 215m summit and 194m bwlch spot height on the large scale Ordnance Survey mapping on the Geograph website.


Rhinogydd            Pt. c 222m    c 222m    SH 649 382
This hill’s summit and bwlch height have been estimated from contour interpolation, with the bwlch estimated as c 202m at SH 650 383, giving this hill c 20m of drop.


Arennig            Pt. 205m    205m    SH 730 254
The 205m height for this hill comes from Harvey Maps and the bwlch height is estimated as c 177m at SH 730 260, giving this hill c 28m of drop.


Arennig            Pt. 285m    285m    SH 993 377
This hill was originally in the P30 list under the name of Bryn Cae-pant, which was an invented name partly taken from buildings to the west.  The Pt. notation has now been used for its name as using an invented name is inappropriate.  There is a 258m spot height at SH 993 381 on the area of the bwlch on the large scale Ordnance Survey mapping on the Geograph website, giving this hill 27m of drop.


Arennig            Pt. 278m    278m    SJ 001 378
The area of the bwlch has a 254m spot height at SH 997 379 on the large scale Ordnance Survey mapping on the Geograph website, this gives the hill 24m of drop. 


Arennig            Pt. c 271m    c 271m    SH 985 376
The summit height has been estimated as c 271m and the large scale Ordnance Survey mapping on the Geograph website has a 247m spot height on the area of the bwlch at SH 990 377, giving the hill c 24m of drop.

 
Arennig            Pt. c 264m    c 264m    SH 896 334
The height of this hill has been estimated as c 264m, and with a 241m spot height at SH 898 337 on the area of the bwlch on the large scale Ordnance Survey mapping on the Geograph website, it gives this hill c 23m of drop.


Arennig            Pt. 234m    234m    SH 870 510
The large scale Ordnance Survey mapping on the Geograph website has a 212m spot height on the approximate position where contour interpolation places the critical bwlch at SH 871 508, giving this hill 22m of drop.


Arennig            Pt. 258m    258m    SH 711 360
This hill is positioned just outside of Trawsfynydd and has a summit spot height of 258m on the large scale Ordnance Survey mapping on the Geograph website.  The height of its bwlch is estimated as c 237m at SH 712 360, giving c 21m of drop.


Arennig            Pt. 207m    207m    SH 791 213
The bwlch height is estimated to be c 186m at SH 792 214, giving this hill c 21m of drop.


Arennig            Pt. 296m    296m    SH 723 284
The summit and bwlch of this hill looks as if they are immersed in conifer plantation.  The bwlch height is estimated to be c 276m at SH 721 288, giving this hill c 20m of drop.


Arennig            Coed y Groes    Pt. c 242m    SH 744 209
This hill’s summit and bwlch height have been estimated from contour interpolation.  The area of the bwlch has two spot heights on it, both on the minor road that passes the old Nannau estate.  These are 221m at SH 745 208 and 223m at SH 745 209, both are shown on the large scale Ordnance Survey mapping on the Geograph website.  I’ve investigated this area on Google Maps, and although not conclusive I’ve opted for a bwlch height of c 222m at SH 74528 20926, giving this hill c 20m of drop.


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


No comments: