Modelling of the geographical information system network component

This paper presents a data model and some considerations on the path operator to manage networks with a Geographical Information System. The data model is based on the merge of the graph theory concepts and the object-oriented paradigm. The introduction of the Master_nodes (resp. Master_edges) allows to define a node (resp. an edge) as an abstraction of a sub-network. A network can be defined using several levels of definition (detail) following the importance of the nodes (resp. the edges) within an application. The object-oriented concepts are applied to the alphanumerical data part and to model the topology of the graph. The data manipulation operators are basic operators. These operators are: the union, the intersection and the difference. More elaborated operators (i.e., path under constraints) are obtained by combining these basic operators. We present some considerations on the path operator in a GIS context and introduce the concept of "the Open Graph Assumption" and the notion of direction. These notions take full advantage of the data model. They represent an alternative way of defining the path operator. This modelling is well adapted to take into account the multi-levels networks (i.e., the definition of a view in the context of multi-users configuration or the introduction of the generalization).