GIS (Geographic Information Systems) software today provides decision makers and land administrators with geometric and descriptive data management and processing tools. The benefits from these tools in an organization need no longer be demonstrated. However, descriptive and geometric forms are far from the only forms in which information can be represented. Their use allows only a partial modeling of the wealth of information in the real world.This paper consists of a reflection on the problem of integrating information in a GIS. The current situation as well as varied approaches possible for this integration are described. This is a starting point for the creation of a coherent framework in which diverse research efforts on modeling and representing spatial knowledge can take place. The accent is placed on the notion of referential representation (for example: spatial, schematic, descriptive) and on the necessity of this type of references to complete conceptual modeling from a developer's view of a GIS application integrating information. We present many examples in which the use of different representation referencing schemes is necessary for management and planning. These include traffic management, electrical engineering, geography. Finally, an example illustrates some partial solutions.