Figure 1
a) Plot showing the density and distribution of hillforts across the entire Hillforts Atlas. b) Plot showing the five main clusters with the density plotted based on the data for each region. (Source data: Lock & Ralston 2022c).
Figure 2
Top) Three plots showing the inter quartile range (IQR) and the 1st and 4th quarters of the Enclosing Area 1 filed. This shows that 50% of hillforts are small to medium-sized forts. Tiny forts are concentrated toward the west coast of Scotland and along the west coast of Ireland while large hillforts are distinct from the Welsh forts and are concentrated in Southwest England. Bottom) Box plots showing the central 50% of Enclosing Area 1 data by regional grouping with whiskers extending to 95.6%. (Source data: Lock & Ralston 2022c).
Figure 3
a) The density of Cropmark Hillforts. This distribution highlights how aerial survey has amplified what is a meaningful cluster in Southeast Scotland (Figure 1a) in a way that is not seen elsewhere. b) This density plot shows a cluster of hillforts dated between 800–400BC, focussed over south-central England. A long history of excavation in this area, compared to little excavation elsewhere, has led to a clustering of datable material that gives a misleading impression that there is an atlas-wide concentration of activity in this area during this period. c) Reviewing the proportion of dated hillforts by region (see Figure 1b) reduces the atlas-wide bias and highlights regional differences such as a peak in Irish forts dated to the late Bronze Age and the continued importance of forts in Northwest Scotland in the Early Medieval period. (Source data: Lock & Ralston 2022c).
Figure 4
A data-driven classification for the typical fort from the northwestern cluster, derived from fourteen Hillforts Atlas attributes, which apply to 50% or more of the regional cluster, or are the dominant attribute, within their class, in this region. (Source data: Lock & Ralston 2022c).