NDG ISO Metadata V1.0X
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NERC Environmental Data Portal NDG Metadata Profile Andrew Woolf 3/12/2008 NERC Environmental Data Portal December 3, 2008 Revision history Version Contributors Date Changes 1.0 Andrew Woolf 2008-12-03 initial version Contents Background ............................................................................................................................................. 4 Overview: GCMD Directory Interchange Format (DIF) ........................................................................... 5 GCMD DIF v9.4 .................................................................................................................................... 5 GCMD Valids ....................................................................................................................................... 7 NDG extensions ................................................................................................................................... 7 Overview: ISO metadata ......................................................................................................................... 8 NERC Profile .......................................................................................................................................... 11 Cross-walk ......................................................................................................................................... 11 Issues ................................................................................................................................................. 24 Missing elements .......................................................................................................................... 24 CodeList Mappings ........................................................................................................................ 24 CodeList/thesaurus management ................................................................................................. 24 Crosswalk semantics ..................................................................................................................... 24 ISO core metadata ........................................................................................................................ 24 Multiple mappings ........................................................................................................................ 25 UML model ........................................................................................................................................ 26 Annex A: GCMD v9.4 XML schema ....................................................................................................... 27 Annex B: GCMD Science Keywords ....................................................................................................... 34 Annex C: GCMD Earth Science Services Keywords ............................................................................... 53 Annex D: GCMD Chronostratigraphic Unit Keywords ........................................................................... 55 Annex E: GCMD URL Content Type Keywords ...................................................................................... 56 Annex F: GCMD Data Center Keywords ................................................................................................ 57 Annex G: GCMD IDN Node Keywords ................................................................................................. 100 Annex H: GCMD Location Keywords ................................................................................................... 102 Annex I: GCMD Project Keywords ....................................................................................................... 109 Annex J: GCMD Instrument Keywords ................................................................................................ 125 Annex K: GCMD Platform Keywords ................................................................................................... 140 Annex L: GCMD Data Resolution Keywords ........................................................................................ 147 NDG Metadata Profile Page 2 NERC Environmental Data Portal December 3, 2008 NDG Metadata Profile Page 3 NERC Environmental Data Portal December 3, 2008 Background The current NERC Data Grid (NDG) Discovery Service harvests metadata from NDG providers into a central repository which is available for searching through a web service interface. Web-based portals (including the main NERC Discovery Portal) provide a simplified user-oriented interface. Metadata harvesting is performed using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). While OAI-PMH is neutral with respect to the underlying metadata format, NDG has initially focused support on the Global Change Master Directory’s (GCMD) ‘Directory Interchange Format’ (DIF). This reflects the history of NDG, having been granted a first round of funding before recent ISO metadata standardisation work was stable. Moreover, while the FGDC’s Content Standard for Digital Geospatial Metadata (CSGDM) was widely used by national (especially US) agency providers, the DIF was more widespread amongst academic and scientific providers 1. However, with the publication in 2003 of the ISO Technical Committee 211’s (Geographic information/Geomatics) standard (ISO 19115:2003) on metadata for geographic information, and its subsequent adoption in 2005 by Europe (EN ISO 19115:2005) and the UK (BS EN ISO 19115:2005), as well as internationally, there is a growing level of support (both de facto and de jure ) for the ISO standard. The current work was funded under the NERC Environmental Data Portal project, with the objective of defining a profile of ISO 19115 containing equivalent information content to the currently adopted v9.4 DIF standard. The approach of first defining a ‘DIF-profile’ of ISO 19115 is a low-barrier first step down a path towards adoption of ISO 19115 as the core metadata standard for NERC. Appropriate next steps would be to evolve the ‘DIF-profile’ into a ‘NERC-profile’, and then to adopt a profile conformant to INSPIRE and UK GEMINI v3 (when published). An ad-hoc NERC Metadata Group has been convened by NERC’s Data Management Advisory Group (DMAG) as a forum within which key NERC data managers may discuss NERC metadata standards. It is expected that this group would play a significant role in future evolution of the profile presented here. 1 For instance the Joint Committee on Antarctic Data Management (JCADM) has chosen DIF as the metadata format for the Antarctic Master Directory ( http://www.jcadm.scar.org/index.php?id=397 ). Similarly, the Intergovernmental Oceanography Commission’s International Oceanographic data and Information Exchange (IODE) has adopted DIF for its Marine Environmental Data Inventory (MEDI, http://ioc.unesco.org/medi/format.html ). NDG Metadata Profile Page 4 NERC Environmental Data Portal December 3, 2008 Overview: GCMD Directory Interchange Format (DIF) GCMD DIF v9.4 The GCMD Directory Interchange Format v9.4 has been adopted by NDG as its standard metadata format. The DIF has a twenty year history, and is now updated in sync with GCMD’s metadatabase software and online authoring tool (docBUILDER). Version 9 was first released June 2004, with v9.4 released in March 2005. The current version (9.8) was released June 2008. Table 1: Recent DIF version history Version Release date 9 June 2004 9.3 February 2005 9.4 March 2005 9.5 February 2006 9.6 July 2006 9.7 April 2007 9.7.1 June 2007 9.8 June 2008 The main guidance to using the DIF is provided through a (presumed normative) XML schema 2 and an online “Directory Interchange Format (DIF) Writer's Guide”3. The latter includes guidance on compliance level for elements. These element compliance levels themselves have changed over time, Table 2. Table 2: Evolution of DIF element compliance levels DIF version Date Element compliance levels 9 June 2004 required / not required 9.7 April 2007 required / recommended / optional 9.8 June 2008 required / highly recommended / recommended Annex A contains a listing of the DIF v9.4 XML schema, and Table 3 below lists the elements with their conformance level. Table 3: DIF v9.4 element conformance based on DIF Writer’s Guide mandatory optional Entry_ID Personnel Location Originating_Center DIF_Creation_Date Entry_Title Data_Set_Citation Data_Resolution Distribution Last_DIF_Revision_Date Parameters Instrument 4 (Sensor_Name) Project Multimedia_Sample DIF_Revision_History ISO_Topic_Category 5 Platform 6 (Source_Name) Keyword Reference Future_DIF_Review_Date Data_Center Temporal_Coverage Quality Discipline Originating_Metadata_Node 7 Summary Paleo-Temporal_Coverage Access_Constraints Related_URL Metadata_Name Data_Set_Progress Use_Constraints Parent_DIF Metadata_Version Spatial_Coverage Data_Set_Language IDN_Node 2 Current version available at: http://gcmd.nasa.gov/Aboutus/xml/dif/dif_v9.7.1.xsd 3 Available at: http://gcmd.nasa.gov/User/difguide/difman.html 4 Sensor_Name in the XML schema 5 Elements mandatory in the DIF Writer’s Guide are also mandatory in the XML schema, with the exception of ISO_Topic_Category, which is optional in the XML schema. 6 Source_Name in the XML schema 7 Originating_Metadata_Node is a DIF element in the XML schema not documented in the DIF Writer’s Guide NDG Metadata Profile Page 5 NERC Environmental Data Portal December 3, 2008 A UML model for the DIF v9.4 is illustrated in Figure 1. Figure 1: UML model for the DIF v9.4 NDG Metadata