Mapping Mountains – Trimble Surveys – Way Stone Edge

 

13.04.26  Blake Moor (SD 971 212) 

Blake Moor (SD 971 212)

Over recent times, trips to the moors above Burnley have taken place twice a year; usually in April and October; one where the greenery and springs warmth is beginning and the other when autumnal colours are predominant.  As with most planned trips in Britain they are weather dependent and especially so for hill walking.  This visit was no different with heavy localised showers forecast for the first day of our two day visit and rain heading up from the south during the afternoon of our second day.

I drove to Mark’s and he then drove north to meet John outside the White House pub at the top of the A58 road.  On our way we had a detour in and around Rochdale to acquaint ourselves with the splendours of this town.  It’s always good to see Mr Kirk and once parked and the customary hand shakes and hugs were had, we were soon happily seated in the pub for a lunchtime meal.  Afterward it was time to visit the hill. 

Meeting place, meal and the start of our walk; the White House pub

Our chosen hill for the day was Blake Moor, which is typical of much of these hills as it’s dominated by open surrounds and consists of heather and moor grass, with an occasional rock outcrop adding interest.  After our meal I quickly got my walking boots on and headed up the road and through a gate to join the good track leading northward beside the Blackstone Edge Reservoir. 

Our inward track

If not for this track and its continuation the hill would be a wild affair with much heather and no doubt bog to walk through.  However, the track gave a semblance of serenity to the surrounds as it made its way north leaving the first reservoir before joining the next three; these are the Little Hazzles Reservoir where a pair of Canada Geese croaked their annoyance of vacating their spot on the track as we approached.  The other two are the White Holme Reservoir which we visited on our downward route and the most northerly; the Warland Reservoir. 

One of the Canada Geese

I’d set off wearing trousers and light fleece coat but the open skies with blue and intermittent cloud meant I was soon over heating.  By now John had caught me up and as we waited for Mark I took the opportunity to convert my trousers to shorts.  Waiting beside one of the reservoirs proved a welcome few minutes rest before we continued toward the southern edge of the Warland Reservoir, here we followed the continuation of the thin ribbon of water that constitutes the Little Hazzles Reservoir, before leaving the welcome confines of the track and heading up in to heather and moor grass for a direct approach toward the high point of Blake Moor. 

John on the green track beside the Little Hazzles Reservoir

By now dark grey shower cloud was massing to our east, with little wind the showers were no doubt slow moving.  As the track petered out we followed a semblance of a path as it headed up on to the higher moor.  The high point of Blake Moor is approximately 200 metres south-eastward from a triangulation pillar, which had been a prominent white indicator on the horizon during much of our inward walk.  We were soon on the top with much of the hill consisting of the customary moor grass and heather. 

Heading for the summit

As this hill had been LIDAR’ed I had no intention of Trimbling it, but still placed the survey equipment on top of my rucksack on the high point of the hill for the customary summit photograph. 

The summit of Blake Moor

We debated heading back the same way, but decided on following a fence roughly south-east down to the eastern end of the White Holme Reservoir, with a path on the western side of the fence giving encouragement for a relatively easy downward route.  This would also give us a circular walk instead of the there and back option. 

On the track beside the White Holme Resrvoir

By the time we reached the track on the southern edge of the expanse of water I was in head down and plodding mode.  We only stopped occasionally, for me this was to take a photo looking across the waters or toward the distant hazy spires of Manchester which stood out on the horizon. 

The distant spires of Manchester

By now my two colleagues were slowly pulling ahead leaving me to my own devices.  Initially I was in no particular hurry, although the threatening build up of late afternoon deep grey shower cloud made me quicken my pace, with the easterly mass of cloud still lingering, but now showers were breaking out closer to where we were.

I made it back to the awaiting cars where John and Mark were getting their boots off, dry from any threatening rain and happy in the knowledge that another hill had been visited and partially explored. 

   

Survey Result: 

               

Blake Moor 

Summit Height:  420.9m (LIDAR)  

Summit Grid Reference:  SD 97191 21217 (LIDAR)

Col Height:  382.4m (LIDAR)

Col Grid Reference:  SD 96557 19725 (LIDAR) 

Drop:  38.5m (LIDAR)

Dominance:  9.14% (LIDAR)

 

 

For further details please consult the Trimble Survey Spreadsheet 

Mapping Mountains – Hill Reclassifications – The Fours – The 400m Hills of England

 

Shadwell Hill (SO 201 865) – Sub-Four addition

There has been an addition to the listing of the The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Shadwell Hill (SO 201 865)

The criteria for the list that this addition applies to are:

The Fours – The 400m Hills of England - English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list is a sub list entitled the Sub-Fours, the criteria for which are all English hills at or above 400m and below 500m in height that have 15m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available to download in Google Doc format from the Mapping Mountains site.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Shadwell Hill, and this was derived from local enquiry conducted by Aled Williams, and it is adjoined to the Cilfaesty group of hills, which are situated adjoined to the Welsh border, and it is positioned with the A489 road to its north and a minor road and the B4368 road to its south, and has the village of Ceri (Kerry) towards the north-west.

When the Introduction to the first group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published by Mapping Mountains on the 10^th September 2022, it was announced that the accompanying sub lists were being revised with the two 390m categories dispensed with and the criteria and name of the 400m Sub-Fours revised.  The one accompanying sub list is now named the Sub-Fours with its criteria being all English hills 400m and above and below 500m in height that have 15m and more and below 30m of drop.

Prior to this revision this hill was listed with an estimated c 13m of drop, based on the 495m summit spot height adjoined to a triangulation pillar that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 482m col height, based on interpolation of 5m contouring between 480m – 485m. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the addition of this hill to Sub-Four status is due to LIDAR analysis, resulting in a 495.8m summit height and a 480.5m col height, with these values giving this hill 15.4m of drop, which is sufficient for it to be classified as a Sub-Four.               

The full details for the hill are:

Group:  Cilfaesty

Name:  Shadwell Hill

OS 1:50,000 map:  137

Summit Height:  495.8m (LIDAR)

Summit Grid Reference:  SO 20154 86570 (LIDAR)

Col Height:  480.5m (LIDAR)

Col Grid Reference:  SO 20255 87067 (LIDAR)

Drop:  15.4m (LIDAR)

 

For the additions, deletions and reclassifications to The Fours – The 400m Hills of England reported on Mapping Mountains since the December 2013 publication of the 1^st edition of this list by Europeaklist please consult the following Change Registers:

 

The Fours

 

Sub-Fours

 

Myrddyn Phillips and Aled Williams (May 2026)

Mapping Mountains – Hill Reclassifications – Y Pellennig – The Remotest Hills of Wales

Llethr Gwaered (SN 795 626) – Pellennig addition 

There has been an addition to the listing of Y Pellennig – The Remotest Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Llethr Gwaered (SN 795 626)

The criteria for the list that this addition applies to are:

Y Pellennig – The Remotest Hills of Wales - Welsh hills whose summit is at least 2.5km from the nearest paved public road and the hill has 15m minimum drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available as a downloadable e-booklet and print-booklet version on Mapping Mountains Publications with the up-to-date master list available to download on the Mapping Mountains site in Google Doc format.

Y Pellennig - The Remotest Hills of Wales by Myrddyn Phillips and Aled Williams

The name the hill is listed by is Llethr Gwaered, and it is adjoined to the Drygarn Fawr group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B1), and it is positioned with a minor road to its north-west, and has the village of Pontrhydfendigaid towards the north-west.

When the original list that later became known as the Y Pellennig – The Remotest Hills of Wales was first compiled, this hill was not included with subsequent documentation giving it an estimated c 13m of drop, based on an estimated c 488m summit height based on interpolation of its uppermost 480m ring contour, and the 475m bwlch spot height that appears on the Ordnance Survey 1:25,000 Explorer map. 

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

Since the original compilation of this list there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites.

One of the mapping resources now available online is the WalkLakes website which hosts an interactive map originated from the Ordnance Survey Open Data programme.  This map has many spot heights not on other publicly available maps and has a 489m summit spot height for this hill, and when coupled with the aforementioned 475m bwlch spot height, these values would give this hill 14m of drop. 

Extract from the interactive mapping hosted on the WalkLakes website

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.

Therefore, the addition of this hill to Pellenig status is due to LIDAR analysis, resulting in a 489.5m summit height and a 468.3m bwlch height, with these values giving this hill 21.2m of drop, which is insufficient for it to be classified as a Pellennig. 

The two Llethr Gwaered Pellennig summits; SH 795 626 and SN 801 625

Although this hill was originally unclassified, its adjacent 490m map heighted summit positioned at SN 801 625 was given Pellennig status.  As LIDAR gives this hill as 0.1m lower with 15.0m of drop compared to the summit of the hill positioned at SN 795 626, their respective bylchau are swapped and where there was just one listed Pellennig there are now two Pellennig hills. 

 

The full details for the hill are: 

Group:  Drygarn Fawr

Name:  Llethr Gwaered

OS 1:50,000 map:  147

Summit Height:  489.5m (LIDAR)

Summit Grid Reference:  SN 79564 62624 (LIDAR)

Bwlch Height:  468.3m (LIDAR)

Bwlch Grid Reference:  SN 79609 63025 (LIDAR)   

Drop:  21.2m (LIDAR) 

Remoteness:  3.800km (LIDAR)

 

For the additions and deletions to Y Pellennig – The Remotest Hills of Wales reported on Mapping Mountains please consult the following Change Register:

 

Y Pellennig – The Remotest Hills of Wales

 

Aled Williams and Myrddyn Phillips (May 2026) 

Mapping Mountains – Significant Name Changes – The Welsh P15s

 

Tai Isa (SH 780 620) 

There has been a Significant Name Change to a hill that is listed in The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Tai Isa (SH 780 620)

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

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The hill is adjoined to the Carnedd Llywelyn group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A1), and it is positioned with minor roads to its north-west and south, with the B5106 road to its east, and has the town of Llanrwst towards the east.

When the listing that became known as The Welsh P15s was being compiled, this hill was listed under the point (Pt. 192m) notation, with an estimated c 15m of drop, based on the 192m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 177m bwlch height, based on interpolation of 10m contouring between 170m – 180m. 

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 70 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 named Tai Isa in the apportionments, with the details on the Tithe map appearing in the parish named as Llanrhychwyn and in the county named as Caernarfonshire. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the The Welsh P15s is Tai Isa, and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Carnedd Llywelyn 

Name:  Tai Isa 

Previously Listed Name:  Pt. 192m 

OS 1:50,000 map:  115

Summit Height:  193.2m (LIDAR)                                                           

Summit Grid Reference:  SH 78082 62044 (LIDAR)                                                  

Bwlch Height:  175.65m (LIDAR) 

Bwlch Grid Reference:  SH 77922 62033 (LIDAR) 

Drop:  17.6m (LIDAR) 

 

Myrddyn Phillips (May 2026)

 

Mapping Mountains – Significant Height Revisions – 600m Twmpau and The Welsh Highlands – Uchafion Cymru

Craig Ysgafn (SH 659 443) 

There has been a Significant Height Revision to a hill that is listed in the 600m Twmpau and the The Welsh Highlands – Uchafion Cymru, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Aled Williams. 

LIDAR image of Craig Ysgafn (SH 659 443)

The criteria for the two listings that this height revision applies to are:

600m Twmpau – Welsh hills at or above 600m and below 700m in height that have 30m minimum drop, with an accompanying sub category entitled the 600m Sub-Twmpau consisting of all Welsh hills at or above 600m and below 700m in height that have 20m or more and below 30m of drop.  With the word Twmpau being an acronym standing for thirty welsh metre prominences and upward.  The list is authored by Myrddyn Phillips and is published on Mapping Mountains in Google Doc format.

600m Twmpau by Myrddyn Phillips

The Welsh Highlands – Uchafion Cymru – Welsh hills at or above 500m in height with 15m minimum drop, with an accompanying sub list entitled the Welsh Highland Subs, the criteria for which is all Welsh hills at or above 500m in height with 10m or more and below 15m of drop.  This list is authored by Myrddyn Phillips and Aled Williams with the Introduction to the list published on Mapping Mountains in November 2015 and the latest update relating to the list published on Mapping Mountains in January 2023.

The Welsh Highlands - Uchafion Cymru by Aled Williams and Myrddyn Phillips

The name the hill is listed by is Craig Ysgafn and it is adjoined to the Moelwyn Mawr group of hills, which are situated in the north-western part of North Wales (Region A, Sub-Region A2), and it is positioned with the A4085 road to its west, the A487 road to its south and the A496 road to its east, and has the town of Blaenau Ffestiniog towards the east north-east.

When the list of Welsh 500m P15s that later became known as the The Welsh Highlands – Uchafion Cymru was first compiled, this hill was listed with an estimated c 26m of drop, based on the 689m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 663m bwlch height, based on interpolation of 10m contouring between 660m – 670m. 

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

However, it was not until LIDAR became available that the details for this hill could be accurately re-assessed.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

LIDAR summit image of Craig Ysgafn (SH 659 443)

LIDAR analysis gives the summit of this hill as 690.0m positioned at SH 65994 44332, and when compared to its originally listed summit height this comes within the parameters of the Significant Height Revisions used within this page heading, these parameters are:

The term Significant Height Revisions applies to any listed hill whose interpolated height and Ordnance Survey, Harvey or other interactive map summit spot height has a 2m or more discrepancy when compared to the survey result produced by the Trimble GeoXH 6000 or analysis of data produced via LIDAR.  Also included are hills whose summit map data is missing an uppermost ring contour when compared with the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 690.0m and this was derived from LIDAR analysis, this is 1.0m higher than the originally listed summit height of 689m, which was based on the spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and importantly this height signifies that an uppermost 690m ring contour is missing from this map.

 

ills of Wales, and are reproduced below@

The full details for the hill are:

Group:  Moelwyn Mawr

Name:  Craig Ysgafn

OS 1:50,000 map:  124

Summit Height (New Height):  690.0m (LIDAR)

Summit Grid Reference:  SH 65994 44332 (LIDAR)  

Bwlch Height:  663.4m (LIDAR)

Bwlch Grid Reference:  SH 66001 44596 (LIDAR)

Drop:  26.6m (LIDAR)

 

Myrddyn Phillips and Aled Williams (May 2026)