12 Annex A – Relationship to CEN DATEX II Data Modelling Concept and Framework

This data model defined in this document draws inputs from a number of sources including the CEN DATEX II series of standards.

By choice, the Alliance for Parking Data Standards has substantively adopted the DATEX II modelling approach, as this may facilitate simpler integration, at a later date, to data concepts and standards defining road traffic management and information concepts.

This model corresponds to the Level C model as defined in EN 16157-1 – in as much as DATEX II modelling concepts have been largely adhered to but this model is not purely an extension of the DATEX II platform independent data model.

There are some instance of divergence between this model and DATEX II modelling concepts, but these exist primarily at a data definition rather than modelling level. Some examples include:

− This model supports the use of a wider range of country codes, language codes and currency codes than supported in DATEX II (which is European focussed). In this model these refer to external codelists; − This model supports non-SI measurement units that are particularly prevalent in the the

USA (e.g. feet, pounds weight).

Conformance with this document shall require platform independent models from which platform specific models are generated to comply with the UML modelling rules defined in EN 16157-1 and with the requirements of this model, as defined in this document:

− comply with all stipulated minimum and maximum multiplicity requirements for UML elements and relationships; − comply with all definitions, types and ordering; − employ optional elements as specified; − comply with all expressed constraints.

It should be noted that conformance with all the structural requirements stated above does not necessarily ensure that the informational content of that service will be semantically comprehensible (e.g. the information may correctly structured, but make no sense).