A network collection is a collection or sequence of several networks that belong together, e.g., by building a longitudinal network.
There must be at least one node attribute with the properties of an identifying attribute that is specified in all included networks. An identifying attribute is a node attribute with the following properties:
- a value of this attribute is defined for each node in the network
- each node has a distinct value of this attribute
An identifying attribute of a network collection is an identifying attribute (see above properties) that is defined in each network of the collection. Hence, it can serve for identifying nodes that represent the same instance in the different networks of the collection. If no identifying attribute exists, a network collection cannot be defined. Usually, the node attribute "id" can serve as identifying attribute, but it is also possible to define another.
A network collection is marked as being siena compatible if all included networks contain the same number of nodes.