Topic map connection statistics

Wandora can analyze connectivity of nodes in the topic map. Connectivity analyze is started selecting Layer > Statistics > Layer connection statistics. Following image illustrates a typical output of the tool.

This histogram shows the number of topics having some specific number of associations. Association refers here not only associations but also class-instance relations between topics. The leftmost bar represents topics with no associations, the one after that topics with one association and so on. The green highlighted bar represents the average number of associations each topic has and the red highlight can be moved using the mouse to see the exact values of each bar. In this case the red bar represents topics with 13 associations and the top part of the window tells us that there are 28 of such topics.

The leftmost bar, representing number of topics without connections can be used to determine the number of totally separate topics in topic map i.e. topics without associations, instances or types. Typically the number of totally separated topics in topic map is rather small containing perhaps occurrence and association types and roles. Thus, large number of totally separate topics usually indicate the topic map contains forgotten topics.

Connection count

The formula used to calculate connection count depends on options given to Wandora at count startup. Possible options include:

• If selected, the type topic filters examined topic set. Examined topic must have selected type topic as a class. In other words the examined topic is instance of given type topic. If type topic is not selected, all topics in current layer are examined.
• If selected, the association type topic counts only associations of given type. In other words the connection count rejects all but given associations. If association type topic is not selected, all associations are counted.
• If include instances check box is checked, instance relation is considered as association and the number of instances is added to the number of associations.
• If include types check box is checked, type-of relation is considered as association and the number of classes is added to the number of associations.

The total connection count viewed above the histogram is a sum of connections in topics. Every binary association adds the total connection count by 2 as connection count is calculated for both players. In general every association with n players adds total connection count by n as count is calculated for every player. As a consequence the connection count is usually at least two times larger than the association count.