Our work is developed in the context of spatiotemporal data modeling and more particularly of urban data modeling. Our goal is to propose a methodology describing the overall process of urban data modeling beginning from the design phase until the implementation in an information system. For that, we propose, within a GIS, an approach based on a conceptual model specific to spatiotemporal data modeling MADS, and on an ODBMS for storing and manipulating data. MADS uses spatial, temporal and multi-representation types that are more precise than those of programming languages on which are based ODBMS models. Thus MADS is semantically richer than the object model, and the purpose of this paper is to present the transformation rules of this conceptual model into an object model that keeps (as close as possible) its semantics. \textcopyright 2011 IEEE.