Mapping Mountains – Trimble Surveys – Mynydd Hiraethog

16.01.16  Bryn Maelgwyn (SH 795 805) and Coed Gaer (SH 799 808)

Bryn Maelgwyn (SH 795 805)

This was the third of four relatively small walks in the company of Alex, who’s role as local guide proved beneficial, especially so for the route we were about to take, as the summit of  Bryn Maelgwyn is embedded in tangled woodland with the connection between it and Coed Gear being steep and pathless.

We parked at SH 795 802 where a couple of cars can be left just off the busy A470.  The grey skies that had pervaded the first two walks of the day remained with us, spitting occasional rain drops down from their depths.  Thankfully the rain was not heavy and as the majority of the walk was in woodland we’d be sheltered if its intensity increased.

A footpath leads in to the wood from beside the busy road and I followed Alex a short distance on the path before he veered leftward in to the morass of tangled bracken and undergrowth.  No paths from here on in, seemed to exist, and I was reliant on Alex finding the high point, he’d been here a couple of times before and confidently strode out toward the first false summit and then indicated that the true summit lay further on.  From this first vantage point it was impossible to see a higher point for the hill, but as we continued through the tangle of woodland the true summit soon veered up in front of us.

Alex heading for the summit of Bryn Maelgwyn

The high point of Bryn Maelgwyn proved to be beside a moss laden and partly collapsed wall and under a wind battered tree, with other trees forming a canopy around which were the remnants of discarded bottles and clothes.  These were the after effects of either overnighting in the wood or teenage parties.  We came across three of four examples of this during our walk; all were untidy and unnecessary mess.

An unnecessary mess

Once we decided where the summit lay I set the Trimble on top of my rucksack which was placed on the partly collapsed wall and with Alex’s help measured the offset down to the high point of the hill.  It took the Trimble about 20 minutes until it was activated to gather its five minutes of allotted data, we waited, patiently, chatting a safe distance below it.

Gathering data at the summit of Bryn Maelgwyn

Once the Trimble was closed off Alex led the way down steepening slopes and eventually out of the wood toward the attractive looking Coed Gaer, this hill proved fun as a path led up its western flank which was crowned by a small rock outcrop which had a barb wired fence running its length and which was positioned over steep ground, this was our way up, and one or two moves involving hand on rock and a balancing act getting over the fence, deposited us close to the summit, which consisted of a number of small rock outcrops vying for the accolade of being the highest point.

Steep wooded slopes on Bryn Maelgwyn

The shapely profile of Coed Gaer 

Outside of the wooded summit of Bryn Maelgwyn the hills that we had so far visited had all proved to be excellent vantage points, and as the Trimble gathered another five minute data set I looked out to the south-west toward the sea and snow-capped mountains in the distance. 

The Trimble GeoXH 6000 aligned with the high point of Coed Gaer

Gathering data at the summit of Coed Gaer 

For our brief time on the summit of Coed Gaer the rain had kept at bay, but as we descended through thickening woodland to our inward path the wet stuff started to fall again and would remain with us during our last walk of the day, this was to the top of The Vardre (SH 781 794), otherwise known as Castell Deganwy.  

LIDAR image of Bryn Maelgwyn (SH 795 805)

Postscript: 

Since the summit survey of these hills full LIDAR coverage is now available.  The LIDAR (Light Detection & Ranging) technique produced highly accurate height and positional data that is now freely available for England and Wales.  Consequently the numerical details for these hills has been analysed using this technique, resulting in the LIDAR height and position for each bwlch being used.

Survey Result:

Bryn Maelgwyn 

Summit Height:  102.1m (converted to OSGM15, Trimble GeoXH 6000) (significant height revision)

Summit Grid Reference:  SH 79580 80540 (Trimble GeoXH 6000)

Bwlch Height:  63.5m (LIDAR)

Bwlch Grid Reference:  SH 79893 80558 (LIDAR)

Drop:  38.5m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

Dominance:  37.76% (Trimble GeoXH 6000 summit and LIDAR bwlch)

Coed Gaer (significant name change)

Summit Height:  134.0m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SH 79924 80840 (Trimble GeoXH 6000) (summit relocation)

Bwlch Height:  60.0m (LIDAR)

Bwlch Grid Reference:  SH 81486 81889 (LIDAR)

Drop:  74.0m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

Dominance:  55.25% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble survey spreadsheet click {here}