Nowadays the field of the geomatic applications is in full rise and the number of software specialized in the handling of the space-time data has known a considerable growth over the last decade. Several methods which have been dedicated to the design of GIS (Geographic Information System) applications have been proposed in the literature and some CASE (Computer Aided for Software Engineering) tools helping designers to generate urban and geomatic applications have been implemented (AIGLE, PERCEPTORY, etc.). Currently location based real time applications became increasingly numerous since they appear in various fields. Moreover there is a real need of using spatial localization in urban real time applications. These applications raise several problems. In fact, their architecture must support mathematical models and algorithms which have important capacities of calculations; also it is difficult to take into account the real time granularity. They present also major problems at the design stage because of the absence of a specific standardized formalism. The design and the modelling of real the time geomatic applications must make it easier to formalize the specifications and to bring coherent software tools compared to the user's needs and constraints related to the reactivity and possibly the mobility of the system's components. Thus, we must take into account, at the design stage, the way to model by making the distinction between the phases of storage of data, data posting and processing. Especially one must note that for the real time applications the processing the data differs from an application to another according to the type of time used and the variation from the spatial localization and shape according to time. The phase of the treatment is very important and it is not treated with the folding screen by the various existing methods. Thus, we propose method adressing real time constraints in the field of urban geomatic applications.