The PDS4 Data Dictionary Tool - Metadata Design for Data Preparers

One of the major design goals of the PDS4 development effort was to create an extendable Information Model (IM) for the archive, and to allow mission data designers/preparers to create extensions for metadata definitions specific to their own contexts. This capability is critical for the Planetary Data System - an archive that deals with a data collection that is diverse along virtually every conceivable axis. Amid such diversity in the data itself, it is in the best interests of the PDS archive and its users that all extensions to the IM follow the same design techniques, conventions, and restrictions as the core implementation itself. But it is unrealistic to expect mission data designers to acquire expertise in information modeling, model-driven design, ontology, schema formulation, and PDS4 design conventions and philosophy in order to define their own metadata. To bridge that expertise gap and bring the power of information modeling to the data label designer, the PDS Engineering Node has developed the data dictionary creation tool known as "LDDTool". This tool incorporates the same software used to maintain and extend the core IM, packaged with an interface that enables a developer to create his extension to the IM using the same, standards-based metadata framework PDS itself uses. Through this interface, the novice dictionary developer has immediate access to the common set of data types and unit classes for defining attributes, and a straight-forward method for constructing classes. The more experienced developer, using the same tool, has access to more sophisticated modeling methods like abstraction and extension, and can define context-specific validation rules. We present the key features of the PDS Local Data Dictionary Tool, which both supports the development of extensions to the PDS4 IM, and ensures their compatibility with the IM.