A few words on the Arderin Begs.
Those who keep a sharp eye on the site will have noticed the addition of a new list of hills entitled the Arderin Begs. Briefly, these are hills over 500m in height with a prominence of between 15 and 30m. However, if your interest in the website is for summiteering (aka bagging), I think it is worthwhile explaining further how they fit into our range of lists.
Firstly, 'prominence' is, unsurprisingly, a measure of how prominent a hill is; it is measured by calculating the height of the hill over the col between it and the nearest higher hill.
Up to now, our principal prominence-related lists were:
Vandeleur-Lynam (V-L) – height of 600m+ with prominence of 15m+
Arderins – height of 500m+ with prominence of 30m+
These lists overlap partly; e.g. hills over 600m with prominence over 15m will be V-Ls, but may also be Arderins if their prominence is over 30m.
The inconsistency in the prominence requirement for each list meant that there were a range of hills not currently being listed; those hills of 500–600m, with a prominence of 15-30m. There were a number of significant hills in this category, named on OS maps, regularly mentioned by our contributors and worthy of visiting and recognising. Examples of these hills include Kanturk, Black Rock Mountain and Droppa.
In order to include these hills and to ensure complementarity with MV’s prime list, the Arderins, we relaxed the prominence requirement from 30m to 15m which generated a list of ‘almost Arderins’, the Arderin Begs, which are now defined as 500m+ hills with a prominence of between 15 & 30m.
The Arderins and Arderin Begs form two discrete lists with no overlap. Every V-L is either an Arderin or an Arderin Beg, depending on its prominence.
Finally a couple of practical effects of the process of adding the new hills:
The process was based on OS maps and makes use of averaging of contour lines in cases where no spot height is given. A number of hills with apparent prominences of under 15m resulting from this averaging process, have also been added to the database, on the basis that accurate measurement might at some stage indicate a greater than expected prominence.
The new summits have been allocated grid references based on 6 digits, unless for some reason a more exact reference was available. This is deliberate in that to use a 10-digit reference might have implied a certainty that we don’t have! As a result, some of the summits can be seen to be clearly off station, appearing outside the upper contours in cases. Again, this is the result of using map based analysis and we hope gps-toting members will make use of the ‘Improve Grid Ref’ tool on each hill’s page to help us correct this over time.