ISO 15531-42:2005 specifies a generic framework for the description of topological properties applicable to a wide range of one dimension domains. Developments made in ISO 15531-42:2005 are focused on the time domain, thus providing a universal, self consistent model, independent of any event that may occur, or has already occurred, at a given point in time. The time model specified in ISO 15531-42:2005 enables any software application to provide an accurate time reference to any related event or sequence of events, whether in the past, in the present or in the future. This time model may be used by any application that needs to reference events, actions or sequences of action linked to time or intervals of time simultaneously. According to this, the scope of ISO 15531-42:2005 includes the following: * the description of the topological properties of an one dimension domain; * the description of the time model and of the related definitions; * the EXPRESS definitions of entities, attributes and schemas as prescribed in ISO 10303-11 (the reference manual of the EXPRESS language); * the EXPRESS-G diagrams of the model as prescribed in ISO 10303-11.