1. NDG Discovery Gateway ISO19139 Issues Bryan Lawrence Director of Environmental Data Archival and Associated Research, CCLRC Head of the British Atmospheric Data Centre, NCAS

2. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk Outline 1.Introduction to NDG Discovery 2.ISO19139 Issues a.Profiles and Interoperability b.Extension c.Restriction

3. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk Discovery Metadata Usage

4. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk New Interfaces Some interesting issues: Natural interfaces to support multiple calendars? Non-bounding box polygon notations in grids not the same as the underlying datasets (e.g. for selecting regions near the poles) …

5. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk Metadata extensions and profiles ISO

6. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk Profiles Local Discovery metadata in OAI provider NDG Discovery metadata store Query WS interface O A I H a r v e s t i n g Local metadata store Local Discovery metadata in OAI provider Local metadata store Query Res ults Data Centre 1 Data Centre 2 Generate Portal 1 GUI Portal 2 GUI Feeds e.g. BODC ISO19139 IOC Profile e.g. BADC ISO19139 WMO Profile Original Transformed

7. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk ISO19139 Extensions E.g. CI_Citation Want to add a new element. Straightforward specialisation in UML … Serialization Rules: 1.Create a new schema 2.Create a new element which has Attribute iso-type:CI_Citation 3.Use a substitution group (YUCK) Add new elements Consumption? 1.Parse the instance, strip the unknown element rename using the iso-type attribute, and import the vanilla document. 2.Conceptually easy!

8. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk ISO19139 Restrictions Existing advice on how to do this is confusing and bad … Decision Yesterday: –Create profile in UML. –Define restrictions using the Object Constraint Language –Signal intent to restrict only by stereotyping the generalisation association (name needed) –Serialisation consists of vanilla ISO19139 elements plus schematron constraints. –Instances are then constrained and validated by schematron –(There is an issue with restricting the allowed usage of OCL to afford easy development of automatic code to generate schematron instances)

9. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk UML Restrictions …

10. http://www.badc.nerc.ac.uk http://www.neodc.nerc.ac.uk http://ndg.nerc.ac.uk Next Steps Today: Agree on stereotype name for profiling restriction Requires a joint activity: Collect best practice for use of OCL for profile restrictions Develop canonical limited subset of OCL for profile restriction Some Hard Coding: Extend shapechange (or similar tooling) to support automatic generation of conformant schematron