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. 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.