Mapping Mountains – Trimble Surveys – Moel y Gamelin

05.05.18  Coed Hyrddyn (SJ 200 439)

Coed Hyrddyn (SJ 200 439)

Coed Hyrddyn nestles between two relatively busy A roads and a river and canal, it feels as if the hill has been squeezed in to the landscape as it is dominated by higher hills in all directions, and yet it is relatively prominent for its height and commands extensive views, it can be combined with adjacent hills or as in today, it can be the sole objective making an enjoyable few hours in warm sunshine with good friends.

Lou had set me the objective of a small walk near Llangollen on good paths that would last between 2-3 hours and Coed Hyrddyn seemed the obvious chose.  I’d visited the hill on two previous occasions, the first in December 2003 when I combined a number of hills in a good winter walk, and the second along with John, Graham and Mark when we surveyed the hill for Hump status in February 2013.  On both visits the weather proved somewhat cold with early frost and sleet showers respectively, today the hill was bathed in early summer sunshine.

We started the walk from beside the Motor Museum next to the Llangollen Canal and walked the short distance back up the road to a track on the left which is also a public footpath and heads north toward Abaty Glyn y Groes (Valle Crucis Abbey).

Setting off toward the hill

The land sparkled with summer growth with green fields running with new born lambs and a radiant blue sky above, nearing the Abbey Farm I stopped and chatted with Jonathon Davies and Edward Jones who were working in the adjacent field, and made place-name enquiries, afterward we continued toward the farm and the Abbey.

The Abbey is now under the care of Cadw and was built in 1201 by the Prince of Powys Fadog; Madog ap Gruffydd Maelor.  It fell in to disrepair after the dissolution of the monasteries in 1537, and it still commands attention with its west end entrance striking skyward.

The west entrance to the Abbey

Beyond the Abbey we crossed the A 542 road and used a foot stile to gain the lower slopes of Coed Hyrddyn, these we followed around the hill’s base on a narrow path that led steeply up its northern flank.  To the west and across the River Eglwyseg, Moel y Gamelin dominated the view, almost pyramidal it looked down on all near hills, whilst across to the east Castell Dinas Bran rose in a great lump of a hill.

Heading up the northern flank of Coed Hyrddyn

Moel y Gamelin

Abaty Glyn y Groes and Castell Dinas Bran

The summit ridge of Coed Hyrddyn has a number of rounded and grassed tops with a good path between and the early summer warmth had brought walkers out on to the hill, with a small group standing beside the high point as we made our way toward it.

Heading for the summit

The summit of Coed Hirddyn consists of a small grassed area and as the Trimble gathered its customary five minutes of data I sat with Lou, Debs and Huw and looked out to the west and bathed in the tranquillity and warmth that the day had brought.

Gathering data at the summit of Coed Hyrddyn

After packing the Trimble away we continued on the good path down toward the car park at the southern end of the hill, past stunted gorse bushes as a steam train chugged up the valley below whistling as it went.

Heading down

Once off the hill we sat beside the canal and river with glasses of cider, fizzy water and an ice cream before leisurely walking on the canal tow path back to the car. 

It had been a good way to spend a few hours in the sunshine on a beautiful small heighted hill in another lovely area of the country that I love.

Survey Result:

Coed Hyrddyn (significant name change)

Summit Height:  232.6m (converted to OSGM15, Trimble GeoXH 6000)  232.4m (converted to OSGM15, Leica GS15)

Summit Grid Reference:  SJ 20028 43944 (Trimble GeoXH 6000)  SJ 20029 43943 (Leica GS15)

Bwlch Height:  130.4m (LIDAR)  130.4m (converted to OSGM15, Leica GS15)

Bwlch Grid Reference:  SJ 20049 44655 and SJ 20051 44657 (LIDAR)

Drop:  102.2m (Trimble GeoXH 6000 summit and LIDAR bwlch)  102.0m (Leica GS15)

Dominance:  43.89%

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains – Significant Name Changes – The Fours

Crumma Pasture (NZ 085 061)

There has been a Significant Name Change to a hill that is listed in The Fours, with this being announced when the 2^nd edition of The Fours was published by Mapping Mountains Publications on the 24^th April 2018.

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

The Fours – English hills at or above 400m and below 500m in height that have 30m minimum drop.  Accompanying the main list of The Fours are three categories of sub hills, with this hill listed as a 390m Sub-Four.  The criteria for 390m Sub-Four status are all English hills at or above 390m and below 400m in height that have 30m minimum drop.

The list is co-authored by Myrddyn Phillips and Aled Williams, with the 1^st edition of the list having been published by Europeaklist in December 2013 and by Haroldstreet in January 2014, with the 2^nd edition of the list published by Mapping Mountains Publications and by Haroldstreet on the 24^th April 2018.

The hill is situated in the Northern Pennines and is placed in Region 35, Section 35A with its Cardinal Hill being Great Shunner Fell (SD 848 972).  The hill is positioned with the A 66 road to its north-east and the A 6108 road and the town of Richmond towards its south-east.

When the listing that is now known as The Fours was originally compiled this hill was not included as the sub category did not take in hills below 400m in height, however when the list was uploaded to the RHB Yahoo group file database the hill was listed as unnamed summit.  Subsequently the hill was listed as Weather Hill in the 1^st edition of The Fours when the list was published by Europeaklist in December 2013. 

Hill list authors are prone to list a hill by the name that appears nearest to its summit on contemporary Ordnance Survey maps, without much consideration for its local or historical confirmation, or whether map placement is appropriate, and in the case of this hill Ordnance Survey 1:25,000 Explorer maps position the name of Weather Hill adjacent to a 382m map heighted top and to the north-west of the summit of this hill.

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

Since the original publication of this list on the RHB Yahoo Group file database there have been a number of Ordnance Survey maps made available online, some of these are historical such as the series of Six-Inch maps on the National Library of Scotland website, whilst others are current and digitally updated such as the Interactive Coverage Map hosted on the Geograph website.  Two of the historical maps now available are the Ordnance Survey Draft Surveyors map which formed the basis for the Ordnance Survey One-Inch ‘Old Series’ map, and it was the latter of these maps as well as the Six-Inch map that position the name of Crumma Pasture adjacent to this hill.

The One-Inch ‘Old Series’ was the first map that Ordnance Survey published, and they were based on the preceding Draft Surveyors map.  Their publication culminated from the whole of Britain being surveyed between 1791 and 1874 and the detail gathered therein produced at a scale of one inch to the mile and published in sheet format between 1805 and 1874.  The One-Inch ‘Old Series’ maps for the whole of England are now available online, they are also available in map format as enlarged and re-projected versions to match the scale and dimensions of the Ordnance Survey 1:50,000 Landranger series and are published by Cassini.  This series of maps forms another important part in the study of upland place-names and bridge the time frame leading to the production of the Ordnance Survey base map of the Six-Inch series.

Extract from the Ordnance Survey One-Inch 'Old Series' map

For many years The Ordnance Survey Six-Inch map was the base map for information to be fed on to, the scale was superseded in the 1950s by the 1:10,000 series of maps and was available as sheets until the 1980s when they were digitised.  One of the recurring themes of Ordnance Survey maps is that some of the data are not consistent between the different scales of maps available, this is particularly noticeable for numerical data between the two publicly available scales of 1:50,000 Landranger and 1:25,000 Explorer maps.  However, when studying place-names it is also noticeable that name placement and sometimes composition is not consistent between these lower scaled maps and their larger scaled and older maps of the Six-Inch series.  It is also noticeable that some names appear on the Six-Inch map whilst they do not appear on the smaller scaled maps.  Extensive research has shown that place-name data and numerical data on the series of Six-Inch maps, and especially so for the former’s placement, are more appropriate and accurate compared too much of the information on contemporary maps. 

Extract from the Ordnance Survey Six-Inch map published in 1857

Therefore, the name this hill is now listed by in The Fours is Crumma Pasture and this was derived from the Ordnance Survey One-Inch ‘Old Series’ map as well as the Ordnance Survey Six-Inch map, with map placement for the name of Weather Hill favouring land to the north-west of this hill’s summit.  

The full details for the hill are:

Cardinal Hill:  Great Shunner Fell

Name:  Crumma Pasture

Previously Listed Name:  Weather Hill

 

Summit Height:  392

OS 1:50,000 map:  92

Summit Grid Reference:  NZ 08593 06115  

Drop:  33m

Myrddyn Phillips and Aled Williams (June 2018)

Mapping Mountains – Hill Reclassifications – 30-99m Twmpau

Coed Abergwynant (SH 681 179) – 30-99m Sub-Twmpau addition

There has been an addition to the 30-99m Twmpau list due to LIDAR analysis conducted by Myrddyn Phillips, with the criteria for this list being:

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height with 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 30m and below 100m 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.

This hill did not appear in the accompanying Hills to be surveyed sub list when the original Welsh P30 hills were published on Geoff Crowder’s v-g.me website as it did not meet the criteria for this sub category; however this sub list has now been standardised including the addition of interpolated drop values and heights.

Prior to LIDAR analysis this hill was listed with an estimated c 19m of drop based on an estimated c 93m summit height based on interpolation of the uppermost 90m ring contour and an estimated bwlch height of c 74m based on interpolation of bwlch contouring between 70m – 80m on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

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

The hill takes its listed name from the wood that its summit is situated in; Coed Abergwynant, and it is adjoined to the Cadair Idris group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), with the hill being positioned between the Afon Mawddach to the north-west and the A 493 road to the south-east, and has the town of Dolgellau towards its east.  

If wanting to visit the hill permission to do so should be sought as it is not a part of designated open access land, for those wishing to do so the nearest convenient access point is the A 493 road and a track to the east of the summit.

The addition of Coed Abergwynant to 30-99m Sub-Twmpau status is due to LIDAR analysis conducted by Myrddyn Phillips.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales. 

The 1m DTM LIDAR analysis gives the hill the following details:

Coed Abergwynant

Summit Height:  91.0m

Summit Grid Reference:  SH 68136 17938

Bwlch Height:  69.5m

Bwlch Grid Reference:  SH 67827 17866

Drop:  21.5m

LIDAR image of Coed Abergwynant

Therefore, the 91.0m LIDAR analysis for the summit position at SH 68136 17938 and the 69.5m LIDAR analysis for the bwlch position at SH 67827 17866 gives this hill 21.5m of drop, which is sufficient for 30-99m Sub-Twmpau status.

The full details for the hill are:

Group:  Cadair Idris

Name:  Coed Abergwynant

Summit Height:  91.0m (LIDAR)

Summit Grid Reference:  SH 68136 17938 (LIDAR)

OS 1:50,000 map:  124

Drop:  21.5m (LIDAR)

Myrddyn Phillips (June 2018)

Mapping Mountains – Hill Reclassifications – The Fours

THIS HILL HAS SUBSEQUENTLY BEEN RECLASSIFIED TO DOUBLE SUB-FOUR STATUS

Silver How (NY 324 066) – 390m Double Sub-Four reclassified to 390m Sub-Four

There has been a reclassification to the listing of The Fours due to analysis of data on the OS Maps website, which is the recent replacement for OS Get-a-map.  The Fours is the title for the list of 400m hills of England and takes in all English hills at and above 400m and below 500m in height that have a minimum 30m of drop, the list is co-authored by Myrddyn Phillips and Aled Williams and the 2^nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24^th April 2018.

Accompanying the main list of The Fours are three categories of sub hills, with this hill being reclassified from a 390m Double Sub-Four to a 390m Sub-Four.  The criteria for 390m Double Sub-Four status are all English hills at or above 390m and below 400m in height that have 20m or more and below 30m of drop, with the criteria for 390m Sub-Four status being all English hills at or above 390m and below 400m in height that have 30m minimum drop.  

Prior to analysis of data on OS Maps this hill was listed with c 28m of drop based on the 395m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated col height of c 367m based on interpolation of col contouring between 360m – 370m on the 1:50,000 Landranger and 1:25,000 Explorer maps.

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

The name the hill is listed by is Silver How and it is situated in the Central and Western Fells of the Lake District and is placed in Region 34, Section 34B with its Cardinal Hill being Scafell Pike (NY 215 072).  The hill is positioned above the B 5343 road which is to its south and the village of Grasmere which is to its north-east.

The summit of the hill is a part of designated open access land and can be approached from a number of directions, with public footpaths leading toward the hill from the north, east and south.

The reclassification of this hill to 390m Sub-Four status is due to the analysis of data on the OS Maps website.  This mapping gives contour intervals at 5m which has enabled the interpolated height of the col to be narrowed down when compared to the 10m contour intervals given on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer maps.  Therefore with a 395m summit spot height on the 1:25,000 Explorer map and an estimated col height of c 364m, based on interpolation of col contouring on OS Maps between 360m – 365m, this hill is now listed with c 31m of drop, which is sufficient for its reclassification to 390m Sub-Four status.

Extract from OS Maps

The full details for the hill are:

Cardinal Hill:  Scafell Pike

Summit Height:  395m

Name:  Silver How

OS 1:50,000 map:  90

Summit Grid Reference:  NY 32477 06643

Drop:  c 31m

For the additions, deletions and reclassifications to The Fours reported on Mapping Mountains since the December 2013 publication of the list by Europeaklist please consult the following Change Registers:

The Fours

The Fours – 400m Sub-Four

The Fours – 390m Sub-Four

The Fours – 390m Double Sub-Four

Myrddyn Phillips and Aled Williams (June 2018)

Mapping Mountains – Significant Height Revisions – The Fours - The 400m Hills of England

Black Hill (SX 761 786)

There has been a Significant Height Revision to a hill that is listed in 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 initially conducted by Aled Williams and subsequently by Myrddyn Phillips. 

LIDAR image of Black Hill (SX 761 786)

The criteria for the list this height revision affects 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 are three categories of sub hills, the 400m Sub-Four category, the 390m Sub-Four category and the 390m Double Sub-Four category.  The list is co-authored by Myrddyn Phillips and Aled Williams and the 2^nd edition of the booklet containing this list was published by Mapping Mountains Publications on the 24^th April 2018.

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

The name the hill is listed by is Black Hill, and it is adjoined to the Broad Barrow group of hills, which are situated in Dartmoor in the south-west of the country, and it is positioned with the A382 road to its north-east and the A38 road to its south south-east, and has the village of Widecombe-in-the-Moor to the west south-west and the town of Bovey Tracey to the east.

When the 1^st edition of the The Fours was published by Europeaklist in December 2013, this hill was listed with an estimated c 31m of drop, based on the 412m summit spot height that appears on the contemporary Ordnance Survey 1:25,000 Explorer map and an estimated c 381m col height, based on interpolation of 10m contouring between 380m – 390m.

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 Black Hill (SX 761 786)

LIDAR analysis gives the highest ground on this hill as 414.2m positioned at SX 76101 78646, and 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 or Harvey 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 to the data produced by the Trimble or by LIDAR analysis.

Therefore, the new listed summit height of this hill is 414.2m and this was derived from LIDAR analysis, this is 2.2m higher than its previously listed height of 412m which appears as a spot height on the Ordnance Survey 1:25,000 Explorer map.

The full details for the hill are:

Group:  Broad Barrow

Name:  Black Hill

OS 1:50,000 map:  191

Summit Height (New Height):  414.2m (LIDAR)

Summit Grid Reference:  SX 76101 78646 (LIDAR) 

  

Col Height:  381.0m (LIDAR)

Col Grid Reference:  SX 75841 77803 (LIDAR)

Drop:  33.2m (LIDAR)

Myrddyn Phillips and Aled Williams (June 2018)