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Prominence Hierarchy

Prominence Hierarchy

Prominence can be used to define a hierarchy of peaks on an island. To understand this hierarchy, we must first define the basic notion of a prominence parent/child relationship:

Parent Peaks and their Children

Referring to the island illustration, if Peak A is the highest on the island and Peak C is separated from Peak A by its key col, this makes Peak A the parent peak of Peak C. Similarly, the prominence of Peak B is defined by its height above its key col with Peak C. Peak C is therefore the parent peak of B. Since A is the parent of C and C is the parent of B, then A is the grandparent peak of B.

A Hierarchy of Ancestors and their Descendants

The UK Prominent Peaks replaces the idea of prominence parentage with the concept of ancestors and descendants. Parental links between hills within the same prominence band are set aside. Linkages between a peak and its ancestor in a higher prominence band or its descendant in a lower prominence band become the new focus. Mull, with its 16 Prominent Peaks, provides a good, but manageable-sized example to demonstrate the new relationship of ancestors and descendants.

Compare and contrast the illustrations below and note that the axis on the right is prominence and not height in metres. Following the 1-2-5 Principle, the green band indicates P100 peaks, the yellow band indicates P200 peaks and the red band indicates P500 peaks.

The 1st hierarchy illustration below shows the peaks of Mull with all their parental links. Ben More is the highest point on the island and is the parent for 9 hills, the grandparent for 4 hills and the great-grandparent for 2. The 2nd illustration shows just the links from any hill to its descendants or ancestors in higher or lower bands.

Peaks with parental links

Peaks with links to ancestors and descendants in different prominence bands.

A look at the map shows that there are four ranges of hills on Mull and these correspond to the ancestor-descendant groups defined on the above diagram.

The Ben More family is the largest on Mull whereas Creach Beinn is one of only 15 P500s in the UK with no Prominent Peak descendant. One big advantage of using ancestors and descendants is that these prominence family relationships can then all be contained within the UK Prominent Peak database.

Dun da Ghaoithe Dun da Ghaoithe family P500 H750
Sgurr Dearg   P200 H500
Ben More, Mull Ben More family P500 H750
A'Chioch   P100 H750
Beinn Fhada   P100 H500
Beinn a'Ghraig   P100 H500
Coirc Bheinn   P100 H500
Beinn na Sreine   P200 H500
Corra-bheinn   P200 H500
Cruachan Dearg   P100 H500
Beinn Talaidh   P200 H750
Cruach Choireadail   P100 H500
Beinn a'Mheadhoin   P100 H500
Ben Buie Ben Buie family P500 H500
Beinn na Croise   P200 H500
Creach Beinn Creach Beinn family P500 H500

Splitting the Mull peaks into 4 families, each with a P500 ancestor, is a natural fit with the topography of Mull.

© 2022 Jim Bloomer, Roddy Urquhart in association with UK metric association