1. BADC, BODC, CCLRC, PML and SOC The NERC Metadata Gateway: a product of the NERC DataGrid + ++ + +[ ]= Bryan Lawrence (on behalf of a big team)

2. TECO-WIS, Nov 2006 Outline Introduction to NERC, the NERC Data Centres, and NCAS The NERC DataGrid Project –Key Components: Data Tools, Data Discovery, {Access Control} –NDG Information Environment Key Standards Structures: the ISO Family From CSML, {MOLES}, DIF to ISO19139 (NumSim) Distributed Content Search –Why we did it this way –Our Discovery Architecture NDG Discovery –Now … and –The Future – The “New NERC Metadata Gateway” ISO19139 Best Practice Summary

3. TECO-WIS, Nov 2006 Some Introductions NERC: The Natural Environment Research Council –The major player in UK environmental research –Is both a funding agency, and a conglomeration of “centres”: internal “research” institutes, The British Oceanographic Data Centre (BODC) is part of one of the internal institutes. And external “collaborative” centres, which include: The Plymouth Marine Laboratory The National Oceanographic Centre, Southampton The National Centre for Atmospheric Science, NCAS, mostly embedded in Universities, but part of which is the British Atmospheric Centre (BADC) which is embedded in the CCLRC: Council for the Central Laboratories of the Research Councils –Is about to be replaced by a new entity, which might be called the “Large Facilities Research Council” NERC has seven discipline based designated data centres (including the BODC and BADC), and requires as much integration of data access as possible. –From discovery to utilisation, from genomics to ecology, from oceanography to atmospheric science, from antarctic science to British geology …

4. TECO-WIS, Nov 2006 http://ndg.nerc.ac.uk British Atmospheric Data Centre British Oceanographic Data Centre Complexity + Volume + Remote Access = Grid Challenge NCAR

5. TECO-WIS, Nov 2006 If it’s not obvious Lots of organisations –Varying membership, and trust internally and between each other is not consistent. Lots of priorities –Not all organisations are “about” data Different internal storage structures –Data stored in variety of databases and filesystems. –Some things well documented, but not automated –Some things automated, but information content is sparse … Integrating data access non-trivial And none of that includes the important relationships with customers and collaborators!

6. TECO-WIS, Nov 2006 Key Components Discovery Tools Discovery Portal –Metadata Search –Direct Links to Data and Services Data Tools Slice and Dice Visualisation Manipulation Access Control Systems are resource limited Data may access may be restricted by license Metadata Structures to support all the above

7. TECO-WIS, Nov 2006 Standards Landscape Or two: ISO TC211 Standards, e.g –ISO 19101: Geographic information – Reference model –ISO 19103: Geographic information – Conceptual schema language –ISO 19107: Geographic information – Spatial schema –ISO 19108: Geographic information – Temporal schema –ISO 19109: Geographic information – Rules for application schema –ISO 19111: Geographic information – Spatial referencing by coordinates –ISO 19115: Geographic information – Metadata Open Geospatial Consortium Specs –Geographic Markup Language, a toolkit for building data descriptions –WMS, WCS, WFS, WPS: the Web (Map, Coverage, Feature, and Processing) services.

8. TECO-WIS, Nov 2006 Standards ISO 19101: Geographic information – Reference model A geospatial dataset… …consists of features and related objects… …in a defined logical structure… …delivered through services… …and described by metadata.

9. TECO-WIS, Nov 2006 Data Description Standards Geographic ‘features’ –“abstraction of real world phenomena” [ISO 19101] –Type or instance –Encapsulate important semantics in universe of discourse –“Something you can name” Application schema –Defines semantic content and logical structure –ISO standards provide toolkit: spatial/temporal referencing geometry (1-, 2-, 3-D) topology dictionaries (phenomena, units, etc.) –GML – canonical encoding [from ISO 19109 “Geographic information – Rules for Application Schema”]

10. TECO-WIS, Nov 2006 CSML: Climate Science Modelling Language Fully Featured GML Application Schema, with extensions for –External binary data (Grib, netCDF etc) –Irregular Grids, “Proper” vertical coordinate systems (both activities now on OGC and ISO standards tracks) V1.0 included seven feature types and provided only “data” modelling. V1.0 CSML tooling includes a scanner (creates CSML from netCDF files), and a parser (instantiates python objects which can be manipulated scientifically (based on the XML CSML documents).

11. TECO-WIS, Nov 2006 XML Parser SeeMyDENC Data Dictionary S52 Portrayal Library SENC Marine GML (NDG) Feature Types XML Biological Species Chl-a from Satellite Modelled Hydrodynamics XSLT For each XSD (for the source data) there is an XSLT to translate the data to the Feature Types (FT) defined by CSML. The FT’s and XSLT are maintained in a ‘MarineXML registry’ The FTs can then be translated to equivalent FTs for display in the ECDIS system XSLT Features in the source XSD must be present in the data dictionary. XSD XML The result of the translation is an encoding that contains the marine data in weakly typed (i.e. generic) Features XSLT Phenomena in the XSD must have an associated portrayal ECDIS acts as an example client for the data. Data from different parts of the marine community conforming to a variety of schema (XSD) Measured Hydrodynamics S-57v3 GML XML XSD XML XSD Feature described using S-57v3.1Application Schema can be imported and are equivalent to the same features in CSML’ Slide adapted from Kieran Millard (AUKEGGS, 2005) MarineXML Testbed

12. TECO-WIS, Nov 2006 The Concept of re-using Features Here structured XML is converted to plain ascii text in the form required for a numerical model HTML warning service pages are generated ‘on the fly’ XML can also be converted to SVG to display data graphically Here the same XML is converted to the SENC format used in a proprietary tool for viewing electronic navigation charts. All this requires agreement on standards Slide adapted from Kieran Millard (AUKEGGS, 2005)

13. TECO-WIS, Nov 2006 CSML Round Tripping - 1 Managing semantics UGAS GML app schema XML 55.25 6.5 GML dataset instance conceptual model Conforms to 101 010 New Dataset Application produces parser V1.0 (Python, Complete)

14. TECO-WIS, Nov 2006 CSML Round Tripping - 2 Managing data - 1 parser V1.0 V2 in development 55.25 6.5 GML dataset scanner V1.0 V2 in development GML app schema XML instance 101 010 CF Dataset Application produces CF

15. TECO-WIS, Nov 2006 CSML2: Structure “Affords” Behaviour ISO 19123 coverage class ‘Affordance’ modelled with UML > Moving beyond GML, but staying in the ISO Frame!

16. TECO-WIS, Nov 2006 CSML2: Related to new OGC Observations and Measurements Spec An Observation is an Event whose result is an estimate of the value of some Property of the Feature-of-interest, obtained using a specified Procedure

17. TECO-WIS, Nov 2006 Managing Data 2 101 010 CF Dataset 55.25 6.5 GML dataset scanner XSLT ISO19115 XML PUBLISH DECISION PROCESSES 101 010 CF Dataset Define Dataset Add Information

18. TECO-WIS, Nov 2006 The Most Important Decision What is a dataset? Granularity too coarse: can’t find what you want – not enough information exposed. Granularity too fine: can’t find what you want – buried in unordered results.

19. TECO-WIS, Nov 2006 Distributed Query Options: Harvest or Crawl Distribute Query to known targets versus harvest from known targets and do local query –Timeliness versus Responsiveness Decision: NDG Discovery based on Open Archives Initiative Protocol for Metadata Harvesting –Additional Partners include NCAR, MPI-WDCC, TPAC, UK-MDIP

20. TECO-WIS, Nov 2006 Discovery Metadata Usage XML: Metadata store: can support a limited variety of different xml schema provided WS-interface understands them (need unique xquery for each method, schema pair)

21. TECO-WIS, Nov 2006 Metadata Formats Currently Supporting NASA Global Change Master Directory: Directory Interchange Format (DIF) Experimenting with: Vanilla ISO19139 Dublin Core UK Gemini V1 format Will support following ISO profiles for harvest: (eventually) UK Gemini profile WMO profile IOC profile (whenever) US FGDC profile ALL SIMULTANEOUSLY: XML Database plus appropriate xqueries

22. TECO-WIS, Nov 2006 Simulation in the context of ISO19139: NumSim NDG Products: NumSim

23. TECO-WIS, Nov 2006 NumSim Example

24. TECO-WIS, Nov 2006 Firefox Search Plugin

25. TECO-WIS, Nov 2006 International Discovery - Climate

26. TECO-WIS, Nov 2006 NDG “New Interface”

27. TECO-WIS, Nov 2006 Within Record Scrolling Down

28. TECO-WIS, Nov 2006 New Interfaces (No CSS as yet) SimpleAdvanced Issues: Times (forecast, paleo etc) BBOX (near poles and dateline) Semantic Vocabulary matching (exploiting a new NDG web-service providing thesaurus content, and ontology mapping)

29. TECO-WIS, Nov 2006 Metadata extensions and profiles ISO

30. TECO-WIS, Nov 2006 ISO19139 Background: Designed to exploit as much as possible of the xml-schema machinery Not designed for Humans! Advice: Use in conjunction with a clear concept of why it’s being used: Decide on dataset granularity, and use other metadata schema to describe how to use content (“A” metadata; e.g. an application schema of GML). Devise a profile with utility then: restrict, restrict, restrict. Document. Register.

31. TECO-WIS, Nov 2006 On Restriction ISO19139 is also about INTEROPERABILITY! Don’t follow the ISO19139 advice and produce a new schema! Ensure that your profile instances are valid vanilla ISO19139 Restrict content out-of-band, e.g. schematron, etc. Agree on how you’re going to deploy ISO19139

32. TECO-WIS, Nov 2006 On Extension ISO19139 is also about INTEROPERABILITY! Do follow the ISO19139 advice and produce a new schema! Do what you need for your community, but: Design so that code expecting ISO19139 instances can parse yours! Make it easy for third party code to ignore your content!

33. TECO-WIS, Nov 2006 Summary NDG dealing with heterogeneous environment Successful deployment of OAI with discovery metadata (There are some issues differentiating between model simulations and ordering response sets) Directly linking to and exploiting GML application schema Web Service backends make deployment easier. Communities need to be very careful how they deploy ISO19139