Mapping Mountains – Significant Name Changes – Y Pedwarau – The 400m Hills of Wales and Y Trechol – The Dominant Hills of Wales

Gwastedyn (SN 986 661)

There has been a Significant Name Change to a hill that is listed in the Y Pedwarau – The 400m Hills of Wales and Y Trechol – The Dominant Hills of Wales, with the summit height, bwlch height and their locations, the drop, dominance and status of the hill derived from LIDAR analysis initially conducted by Aled Williams and subsequently by Myrddyn Phillips.

LIDAR image of Gwastedyn (SN 986 661)

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

Y Pedwarau – The 400m Hills of Wales.  Welsh hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list are five categories of sub hills; 500m Sub-Pedwarau, 500m Double Sub-Pedwarau, 400m Sub-Pedwarau, 390m Sub-Pedwarau and the 390m Double Sub-Pedwarau.  The list is co-authored by Myrddyn Phillips and Aled Williams and is published on Mapping Mountains in Google Doc format.

Y Pedwarau - The 400m Hills of Wales by Myrddyn Phillips and Aled Williams

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Hirddywel group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B2), and it is positioned with the A44 road to its north-east and the A470 road to its south-west, and has the town of Rhaeadr Gwy (Rhayader) towards the north-west.

The hill appeared in the original Welsh 400m P30 list compiled by Myrddyn Phillips and published on Geoff Crowder’s v-g.me website, under the transposed name of Gwastedyn Hill, which is a prominent name that appears adjacent to the summit on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.  This is also the name the hill was listed by in the 1^st edition of the Y Pedwarau published by Europeaklist in May 2013.

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

Since publication of the 1^st edition of Y Pedwarau 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.  Two of the historic maps now available online are the Ordnance Survey Draft Surveyors map which formed the basis for the first publicly available Ordnance Survey One-Inch ‘Old Series’ map, and it is the latter and the series of Six-Inch maps that form the basis in the change of the listed name of this hill.

The One-Inch ‘Old Series’ map was the first map that Ordnance Survey produced, and 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 Wales 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 form another important part in the study of Welsh upland place-names and bridge the timeframe leading up to the production of the Ordnance Survey base map of the Six-Inch series, and importantly for this hill and its listed name, it is this map that uses the form Gwastaden adjacent to the summit of this hill.

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

The Ordnance Survey series of Six-Inch maps formed the base map Ordnance Survey used for many decades leading to the production of the 1:10,000 Series of maps, both have now been superseded by the digitised Master Map.  The series of Six-Inch maps are excellent for name placement and especially so compared to the contemporary Ordnance Survey 1:25,000 Explorer map, and it is also the series of Six-Inch maps that places the name of Gwastaden, without the use of the superfluous word Hill, adjacent to the summit of this hill.

Extract from the Ordnance Surveys series of Six-Inch maps

Therefore, the name this hill is now listed by in the Y Pedwarau – The 400m Hills of Wales and Y Trechol – The Dominant Hills of Wales is Gwastedyn, and this form without the superfluous use of the word Hill was derived from the Ordnance Survey One-Inch ‘Old Series’ map and the Ordnance Survey series of Six-Inch maps and substantiated by the 1865 Enclosure Map.

The full details for the hill are:

Group:  Hirddywel

Name:  Gwastedyn

Previously Listed Name:  Gwastedyn Hill

OS 1:50,000 map:  136, 147

Summit Height:  477.4m (LIDAR)

Summit Grid Reference:  SN 98679 66144 (LIDAR)

Bwlch Height:  233.1m (LIDAR)

Bwlch Grid Reference:  SN 99379 68810 (LIDAR)

Drop:  244.3m (LIDAR)

Dominance:  51.18% (LIDAR)

Myrddyn Phillips and Aled Williams (November 2019)