3.3. Network Characterisation
Excluding movements to abattoirs, the dataset comprised 751,003
movements. The annual average networks had 76,205 nodes and 250,334
edges. Table 3 summarises the results obtained from the exploratory
network characterisation of the static networks. The annual and monthly
networks were highly clustered, and their metrics were stronger in the
annual networks (0.38) than in the monthly networks (0.15). The network
diameter (maximum shortest path length) was 20.33 steps in the annual
networks and 17.47 steps for monthly networks, meaning that a maximum of
20 steps in the annual network separated any two premises. The average
number of neighbours was similar in the annual (2.61) and monthly (2.19)
networks, meaning that each node in the network was connected on average
to 2.6 other nodes. The shortest path length ranged from 4.29–4.47,
meaning that it took approximately 4 steps to go between two randomly
chosen nodes in the annual networks and between 3 and 6 steps in the
monthly networks.
In the annual networks, the GWCC contained 98.49% of the active
premises, meaning that trade connections reached almost all nodes. The
GSCC in the annual networks contained 17.62% of the active premises and
10.17% in the monthly networks; in this subset of nodes, there was a
direct path between all pairs of nodes, forming the backbone of the
network and ensuring its overall connectivity.
Table 3. Summary of global metrics of the annual and monthly pig
movement networks in Ecuador (2017–2019).