Behavior of geographic objects holds a critical role in spatial databases. This, along with objects’ position and space-varying attributes, form a minimal set of concepts sufficient to capture spatialpeculiarities in terms of the object-oriented rational. This paper presents the semantics and the graphical notation of a prototypical object-oriented model for the conceptual design of spatial databases: by extending the Object Model of the Object Modeling Technique to the Geographic ObjectModel, we show how the above three concepts fit naturally into any object-oriented tool. We augment this model with the constructs of spatial aggregation and spatial grouping to express the critical aspects of space-varying attributes, object boundary fuzziness and uncertainty, spatial relationships, and attribute generalization. Our proposal integrates the field- and object-based geographic views in one model. The principal idea behind this effort is the incorporation of a set of concepts into any semantic or object-oriented model, to make them communicate at the conceptual level (semantic interoperability).