6 What Makes a Site Important? Centrality, Gateways, and Gravity

Commonly used network construction techniques limit the number of allowed connections on the basis of distance and/or the number of closest neighbours.

“Commonly used and effective network construction techniques limit the number of allowed connections on the basis of distance and/or the number of closest neighbours (see Gorenflo and Bell 1991;Jiménez Badillo 2004;Rivers et al. 2013;Groenhuijzen and Verhagen 2017;Fulminante et al. 2017).”

In most published studies the edges are undirected, but some places act as hubs and others as net suppliers, so edges can be directed with different weights depending on direction of flow.

“In most published studies the edges are undirected, i.e. there is no difference between going to and from a place.However, some places will act as 'hubs', attracting goods, wealth, and workforce, whereas others are only net suppliers of, for example, mineral resources, food, or people.The edges between the network nodes will then be directed and have different weights depending on the direction of”

Maritime networks can more readily be reconstructed based on concepts such as centrality, gravity, and proximal point analysis, whereas land-based commodity flows are hampered by people often choosing apparently suboptimal routes for safety or transaction costs.

“While network analyses of land-based flows of commodities are hampered by the fact that people are known to often choose an apparently suboptimal route of travel for reasons of safety or transaction costs (Seland 2012a), maritime networks can more readily be reconstructed based on concepts such as centrality, gravity, and proximal point analysis (Knappett et al. 2008;Rivers et al. 2013).”

If the assumptions behind XTENT are plausible and significant, then the observations have general repercussions for understanding past networks and connectivity, independent of shortcomings in concepts or flaws in data of individual case studies.

“Provided that the assumptions behind XTENT are both plausible and significant (gravity models are an accepted tool in spatial analysis: Evans et al., 2008;Rivers et al., 2013;Ortman et al., 2015), then these observations have general repercussions for our understanding of past networks and connectivity, that are independent of shortcomings in concepts or flaws in the data of individual case studie”