The data model intended to measure an observation linked to the movement of an item at a certain location and over a given period. This Data Model proposes an evolution of two Data Model by merging them and integrating all the attributes of the initial version of [TrafficFlowObserved] and [CrowFlowObserved] and by extension any type of item that we want to analyze the movements. Attributes `vehicleType` and `vehicleSubType` are removed from the initial data Model in order to become generic `itemType` and `itemSubType` of possible values. (people, Type of vehicle, Type of boat, Type of plane, …).