Mapping Mountains – Significant Name Changes – Y Trichant – The 300m Hills of Wales

 

Top Field (SO 110 879) 

There has been a Significant Name Change to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

Top Field (SO 110 879)

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

Y Trichant – The 300m Hills of Wales.  Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for 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 list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Cilfaesty group of hills, which are situated in Mid and West Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north, west and east and the A483 road farther to its south-west, and has the town of Y Drenewydd (Newtown) towards the north. 

When the original 300m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was listed under the invented and transposed name of Moel Genau, with an accompanying note stating; Name from buildings to the South-West.

Moel Genau

371m

SO110879

136

214

Name from buildings to the South-West.

 

During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day.  My preference was to use farm names and put Pen, Bryn or Moel in front of them.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found. 

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 B211 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 as Top Field, with the details on the Tithe map appearing in the parish of Kerry and in the county named as Montgomery. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Top Field and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Cilfaesty 

Name:  Top Field 

Previously Listed Name:  Moel Genau 

OS 1:50,000 map:  136

Summit Height:  373.8m (converted to OSGM15, Trimble GeoXH 6000)     

Summit Grid Reference:  SO 11015 87958 (Trimble GeoXH 6000) 

Bwlch Height:  346.1m (LIDAR) 

Bwlch Grid Reference:  SO 11279 88639 (LIDAR) 

Drop:  27.7m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (October 2021)

 

 

 

 

Mapping Mountains – Significant Height Revisions – Y Trichant – The 300m Hills of Wales

Top Field (SO 110 879) 

There has been a Significant Height Revision to a hill that is listed in the Y Trichant – The 300m Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

Top Field (SO 110 879)

The criteria for the list this height revision affects are:

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant with the criteria for 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 list is authored by Myrddyn Phillips, with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The name the hill is listed by is Top Field and this was derived from the Tithe map, and it is adjoined to the Cilfaesty group of hills, which are situated in Mid and West Wales (Region B, Sub-Region B1), and it is positioned with minor roads to its north, west and east and the A483 road farther to its south-west, and has the town of Y Drenewydd (Newtown) towards the north. 

When the original 300m height band of Welsh P30 hills was published on Geoff Crowder’s v-g.me website, this hill was included in the Hills to be surveyed sub list with a summit height of 371m, based on the spot height that appears on the Ordnance Survey 1:25,000 Explorer map, with an accompanying note stating; 374m on 1986 1:50,000 map.  On the contemporary Ordnance Survey 1:50,000 Landranger map, the summit spot height is now given as 371m. 

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 image of Top Field (SO 110 879)

LIDAR analysis gives the summit height of this hill as 373.6m, and as the summit has now been surveyed with the Trimble GeoXH 6000 it is this result that is being prioritised for listing purposes 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 summit 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. 

The Trimble GeoXH 6000 gathering data at the summit of Top Field

Therefore, the new listed summit height for this hill is 373.8m and this was derived from a Trimble GeoXH 6000 survey, this is 2.8m higher than the previously listed summit height of 371m which appears as a spot height on the contemporary Ordnance Survey 1:25,000 Explorer map and now also appears on the 1:50,000 Landranger map. 

 

The full details for the hill are: 

Group:  Cilfaesty 

Name:  Top Field 

OS 1:50,000 map:  136

Summit Height (New Height):  373.8m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SO 11015 87958 (Trimble GeoXH 6000) 

Bwlch Height:  346.1m (LIDAR) 

Bwlch Grid Reference:  SO 11279 88639 (LIDAR) 

Drop:  27.7m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (October 2021)

 

 

 

 

 

 

 

 

  

Mapping Mountains – Trimble Surveys – Cilfaesty

14.07.21  Top Field (SO 110 879) 

Top Field (SO 110 879)

When planning the day’s outing I initially did not include this hill, mainly as it is not classified as a P30, but instead a sub, a P20.  The former are collected by the avid hill bagger, at an alarming rate for many, whilst the latter are almost an afterthought, visited by the dedicated few.  However, many P20s are excellent hills in their own right, and being a person who rarely thinks detrimental thoughts about any hill, I try and visit those hills that are classified as P20s when times allow. 

This hill is situated just southward of the previous hill I had visited and was the sixth of seven hills visited and surveyed during the day.  The day had started just after 6.30am on a quiet and tranquil hill known as Pen y Gelli (SO 180 909) and continued to Bryn Pant y Drain (SO 178 885), before visiting the summit of Pen Aran Hill (SO 137 888) and then Cold Weston (SO 141 907).  The fifth hill is another whose uppermost field is known as Top Field (SO 114 890) and it was only a short drive farther south on the same hill ridge and narrow lane until I found a good parking place just below the upper field where the summit of the second Top Field is situated. 

I contemplated heading straight up the field from an adjacent gate, but as this was in full view of a near house, I decided to walk up the lane away from the summit and by doing so I was soon in the adjacent field and doubling back toward the summit of Top Field.  Between me and it was a fence and a little lower an access gate, I opted to loose height to use the gate.  The upper field of Top Field was strewn with thistles interspersed amongst yellowish grass which added colour to the scene. 

Nearing the summit of Top Field

I had LIDARed this hill for its summit and bwlch height and position and when nearing the high point I used the Trimble as a hand-help device to zero in to the summit position compared to the co-ordinates produced from LIDAR analysis.  However, the summit would not be difficult to pinpoint by just using one’s eye. 

LIDAR image of Top Field (SO 110 879)

When at the summit I positioned the Trimble atop my rucksack, took a measurement offset between its internal antenna and the ground at its base, waited for the 0.1m accuracy level to be attained before data should be logged, and once this figure appeared on the screen I pressed ‘Log’ and scampered away so I was below the equipment and therefore not obstructing it from a clear view of those all-important orbiting satellites. 

Gathering data at the summit of Top Field

The Trimble GeoXH 6000 set-up position at the summit of Top Field

Once the allotted five minutes of data were gathered and stored I closed the equipment down, took a few photographs and packed it away.  Having done what I wanted to do I opted for the easier and direct route back to my car and quietly sauntered down the field to the access gate which was close to where I had parked.  Just one hill remained to visit for my seven hills of the day; Trehafren Hill (SO 100 910) which is positioned above a housing estate in Newtown. 

 

Survey Result: 

 

Top Field (significant name change)

Summit Height:  373.8m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision)

Summit Grid Reference:  SO 11015 87958 (Trimble GeoXH 6000)  

Bwlch Height:  346.1m (LIDAR)

Bwlch Grid Reference:  SO 11279 88639 (LIDAR)

Drop:  27.7m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  7.42% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet