You will find Social Network Visualizations of the witnesses of five Scottish kings – David I (1124-53), Malcolm IV (1153-65), William I (1165-1214), Alexander II (1214-49), Alexander III (1249-86)- on the website.
Details about each of these SNA studies can be found using the pages on the sidebar. This page is to offer some general explanation and guidance about how to navigate the graphs. These royal charter co-witnessing graphs have been developed based on who witnessed royal charters together.
If you select ‘King Malcolm IV charter witnesses’ using the drop-down menu, the Gephi sociogram will display. There is a zoom bar at the left of the screen. You can use this or the scroll on your mouse to zoom out and see the whole graph.
Below the zoom bar is a magnifying glass icon. This should be set to ‘on’ when you navigate to the page, so if you place your cursor over the graph, it will magnify part of the graph, allowing you to read the names of people in the PoMS database together with their coloured nodes. Zoom into the middle of the graph and click on Richard de Moreville (d. 1189 or 1190). If you find it hard to select a person, try turning off the magnifying glass feature.
When you click on a person, you will see some information on the left of the screen. This will tell you that person’s PoMS ID number, their gender, some SNA statistics, and a list of the people in their ‘co-witnessing network’, in other words, all the people who witnessed charters of King Malcolm alongside that person. The number of times Richard de Moreville witnessed a charter alongside any given individual is given in brackets. For example, Richard de Moreville co-witnessed with Arnold, bishop of St Andrews, 8 times.
The ‘ego-network‘ of Richard de Moreville will also be highlighted in the graph. If you click on the bottom button, underneath the magnifying glass button, it will make all persons who are not in this ego-network disappear. (If you push this same button any other time, it makes the lines between people (‘edges’) disappear.)
The size of the nodes and people’s names, as well as the darkness of the colour of the nodes, are all reflective of something called ‘Eigenvector centrality’. This is the SNA measurement which best reflects the overall importance of a person within a given network. The simplest form of centrality, Degree, is given in the table on the left. Degree, in this case, is simply the number of other people who have co-witnessed with ‘ego’. Richard de Moreville’s degree is 118: he has witnessed with 118 other people. By contrast, Robert Bruce (II) (d. 1194)’s degree is only 63. Degree tells us how many people ‘ego’ was connected to; whereas Eigenvector centrality also calculates in the ‘importance’ of the people to whom ‘ego’ is connected.
The method of calculating Eigenvector centrality used here expresses this as a percentage of the most important person in the graph. In this graph, Richard de Moreville is that person; he has an Eigenvector centrality of 1.o. By contrast, Robert Bruce II has only an eigenvector centrality of .69 (69%), while Isaac, prior of Scone (d. 1162) has only an eigenvector centrality of 8.7%.