Mapping Mountains – Summit Relocations – 100m Twmpau

Pt. 173.8m (SN 225 503)

There has been a Summit Relocation to the 100m Twmpau (thirty welsh metre prominences and upward) list initiated by a survey with the Trimble GeoXH 6000, with the survey that resulted in this summit relocation being conducted on the 13^th May 2016.

The hill is adjoined to the Rhos Ymryson range of hills and is situated to the north-east of Aberteifi (Cardigan) and to the west south-west of Aberporth, with the high point of the hill being close to the small community of Felinwynt which only comprises a few houses, and as the hill does not possess a name of its own on current Ordnance Survey maps, and as I do not know an appropriate name for it either from local enquiry or from historical research it is being listed under the point (Pt. 173.8m) notation.

Access to the hill is relatively easy as it comprises a large grassy field which has a minor lane running over it in a north to south direction.  However, the high point as surveyed with the Trimble GeoXH 6000 is not on open access land and therefore permission to visit should be sought.

The highest spot height adjoined to this hill on Ordnance Survey maps is 174m and this is positioned on the minor lane and adjacent to where a fence heads westward across a field.  A data set was taken with the Trimble from the high point of the road as well as from what was deemed to be the high point of the adjacent field, the results appear below:

High point of road:  173.7m (173.695m, converted to OSGM15)

High point of field:  173.8m (173.811m, converted to OSGM15)

These two results are very close and there is a possibility that higher ground exists in the field when compared to where the Trimble set-up position was placed.  However, for now this Trimble data is the most accurate that is known for this hill, and although the corner of the field is very close to the high point of the road it is worth itemising this positional change as a summit relocation as many people may just dip their toe on the tarmac instead of visiting the land within the adjacent field.

Therefore, the known higher part of the hill as surveyed with the Trimble GeoXH 6000  is not on the minor lane as ground in the adjacent westerly field is approximately 0.12m higher.

The full details for the hill are:

Cardinal Hill:  Rhos Ymryson

Summit Height:  173.8m (converted to OSGM15)

Name:  Pt. 173.8m

OS 1:50,000 map:  145

Summit Grid Reference (New Position):  SN 22587 50306 

  

Drop:  c 55m

The Trimble GeoXH 6000 gathering data at the summit of Pt. 173.8m, with the minor road where the 174m spot height appears on the ground on the other side of the gorse hedgerow in the background of this photograph

For details on the survey that relocated the summit of this hill.

Myrddyn Phillips (May 2016)

Mapping Mountains – Trimble Surveys – Hafod Ithel

13.05.16  Pt. 173.8m (SN 225 503)

Pt. 173.8m (SN 225 503)

The ethics of roadside bagging may be thought of as dubious, but their convenience and novelty are not to be underplayed as a summit visited is just that, and if that summit just happens to be positioned on a road the ethics of what constitutes a valid ascent are easily dispensed with in favour of another tick in another list.

Today’s roadside grab was a hill that is positioned on the outskirts of Felinwynt, which is a small gathering of houses to the north-east of Aberteifi (Cardigan).  The hill constitutes a large grassed field with a minor road passing over it in a north to south direction.  The upper part of the road has a 174m spot height adjoined to it on Ordnance Survey maps, this is beside a fence in the field, with a 173m spot height given to a patch of land to the south.

I’d been out for 6½ hours earlier in the day around part of the Pumlumon range of hills before driving further south, and wanted a couple of easy P30s to visit before heading to the west of St David’s for tomorrow’s island adventure which Adrian Rayner had organised, and this roadside bag was on the way to Foel y Mwnt, which proved to be my last hill of the day.

It wasn’t difficult to find the high point of the minor road and I parked close to the grass verge, this is as the map indicates as it is opposite where the fence stretches across the greened field to the west.

Gathering data on top of an improvised tripod (my car) at the point where the 174m spot height appears on the ground

The car roof proved to be ideal as an improvised tripod and within a few minutes the Trimble was collecting data positioned 1.42m above the high point of the road.  After packing the Trimble away and as all was quiet hereabouts I decided to investigate the adjacent westerly field.  It took a little clambering to get over the fence but once in the field I marched across it following the fence line and looked back toward the hedgerow and minor road.  The highest part of land was either the hedge or the embankment where the fence was positioned; as both were judged to be man-made constructions I dismissed them as being potential points to survey.  However, as I was now in the field I thought it wise to gather another five minute data set from what looked to be its high point; this at least could be compared to that of the road.

Gathering data in the westerly field

Gathering data in the westerly field with the man-made embankment clearly higher in the background

As the Trimble gathered its customary five minutes of data I sat below and next to the fence, soaking up the afternoon’s sunshine.  Twenty three minutes after arriving I was back at the car having surveyed two potential highest points and having ticked off another P30, next stop the beautiful Foel y Mwnt.

  

Survey Result:

Pt. 173.8m

Summit Height:  173.8m (converted to OSGM15)

Summit Grid Reference:  SN 22587 50306 (summit relocation confirmed)

Drop:  c 55m

Dominance:  31.64%

For further details please consult the Trimble Survey Spreadsheet.