• Introduction
• Basis reference
• Vocabularies
• XML-ISO19115 xsd
• CDI XML examples
• CDI User Interface
• Java Tools
• Incorporation of partner’s CDI XML files into the central CDI Metadirectory

Introduction:

The CDI provides a Common Data Index (metadatabase) to individual datasets, held at partner databases. The CDI gives detailed insight in available datasets at CDI partners and paves the way to direct online data access or direct online requests for data access / data delivery.

The CDI principle is that each participating data centre produces at regular intervals up-to-date CDI metarecords, giving an index overview of the content and coverage of its databases. The partner contributions and their regular updates are centrally collated in a central CDI metadatabase, that is equipped with a CDI user interface, to serve users. CDI has adopted XML and the ISO19115 standard to support standard exchange and interoperability.

Within Sea-Search first a pilot operational CDI system has been developed, including ca. 10 Sea-Search data centres. As part of the SeaDataNet project, that has succeeded the Sea-Search project from 2006 onwards, a full scale implementation of the CDI is in progress, including an automatic updating procedure based upon fast replication and a direct access to datasets by internet.

The development of the CDI is presently coordinated by the SeaDataNet Technical Task Team, consisting of technical and science representatives of IFREMER (FR), BODC (UK), BSH-DOD (DE), NCMR-HNODC (GR), NODC (NL), RIHMI-WDC (RU), OGS (IT), IEO (ES), ENEA (IT), CLS (FR), SMHI (SE), and chaired by MARIS (NL).

The development, management and maintenance of the various CDI components is a joint effort by the SeaDataNet partners. For convenience of CDI partners and data holding centres, interested in becoming a CDI partner, this webpage gives all references and links to all relevant documentation, libraries and software tools.

Basis reference, which all must read before starting:

• Document ‘Common Data Index (CDI) - Version V0 - Metadata Format and full description of XML schema’ documentation 4.00 – prepared by Technical Task Team

This guidance document gives a logical description of the CDI Version 0 format, followed by a description of the CDI V0 XML schema, which is ISO 19115 compliant. This includes all XML tags, syntax and semantics, to be used for preparing CDI XML records in great detail. It gives an explanation how to apply all CDI documentation to generate CDI XML files by data holding centres. It also describes the Java Tools software, that has been developed in the Sea-Search framework and which has been upgraded in the SeaDataNet project. It is available to CDI partners free of charge to support the CDI XML file generation process.

Note: Compared to the pilot CDI in Sea-Search a number of upgrades have taken place in the format, use of vocabularies and JavaTool as part of SeaDataNet. The documentation gives the latest versions, that should be used by partners.

Vocabularies

The CDI-format is supported by a number of controlled lists of standardised terms or vocabularies that cover a broad spectrum of disciplines of relevance to the oceanographic and wider community. CDI partners can browse through these vocabularies and download the latest versions at the following webpage.

XML-ISO19115 xsd file:

For purposes of standardisation, international exchange and interoperability with other systems and networks the International Metadata Standard for Geographic Information ISO19115 has been adopted for CDI. The XML ISO19115 schema (or DTD) is defined and managed by the Technical committee TC211 of the International Organization for Standardization (ISO), who is responsible for making international standards on geographic information (www.isotc211.org). The standard defines more than 300 metadata elements, most of which can be applied optionally. It contains around ten elements, which are mandatory ‘core’ metadata. Moreover one can create profiles and add new elements. The CDI XML format is defined as a subset of this standard, which is fully ISO19115 compliant.

• XML-ISO19115 schema

Examples of generated CDI-XML file:

• Example describing one CTD file containing all the CTD stations measured during one cruise. This one has a multi-parameter relation. The measuring area type is an area.

CDI User Interface:

Java Tools:

Latest version:
Mikado_Java_tool_V0_2.zip

To support CDI partners in generating their CDI XML files a Java Tool has been developed by IFREMER in the framework of the Sea-Search project and upgraded in SeaDataNet. It is called MIKADO and it is available free of charge to CDI partners.

MIKADO also can be used to generate and store EDMED XML files and CSR/ROSCOP XML files. Specific information about these other metadirectories and their formats can be found at:

• http://www.sea-search.net/edmed
• http://www.sea-search.net/roscop

You can download MIKADO as a Zip file. This package contains: configuration files, Mikado.bat file and a user manual. Which will be updated soon. You have to unpack the Zip file in a separate directory. You can then start the program by clicking on: Mikado.bat. For operation of the software, you need to have installed the j2sdk (>1.4) or Java Virtual Machine (JVM).
This Java Tool supports 2 functions:

1. Generating automatically a series of CDI XML files from the partner’s database(s). This requires configuring a cdi.properties file, which will contain the ‘mapping’ between the partner’s database and the CDI XML format and it will include the SQL queries, that support the extraction and possible conversion of items from the partner’s database into the CDI XML fields. Also possible missing fields can be filled by default values via the properties file. The partner’s relational database must be queried with SQL language through a JDBC driver (Java Data Base Connectivity). JDBC drivers are available for most popular relational DBMS (ORACLE, Sybase, Microsoft Access, MySQL, SQL Server, PostGres, … ). Please refer to the web site http://developers.sun.com/product/jdbc/drivers for more information. JDBC drivers implement two protocols to query databases called ‘thin’ or ‘thick’ client. Because the amount of retrieved data is not huge, choose ‘thin’ as a default which is easier to set up and do not requires extra libraries. The format of the cdi.properties file is compliant with java property files and the used syntax is simple:
   • keyword=value
   • Character ‘#’ at the beginning of a line means comment.
   • Keywords must be kept as they are (no change allowed in keywords). Only values must be adapted.
   The Java Tool also checks whether all mandatory fields have been initialized and it checks the generated CDI XML files against XML ISO19115 Schema. More information on the configuring of the cdi.properties file can be found in the Basis Reference document (see above).
2. A user interface to enter and to generate CDI XML files one by one manually by typing in the relevant information for CDI fields. This might be useful for a small amount of CDI entries, but if CDI entries are more numerous then it is advised to use the automatic procedure (see above).

Notes:

• The CDI libraries are included in the Zip file, but you are advised to update these libraries regularly with possible new versions (see above)
• The Java Tool also supports generating EDMED XML files and CSR XML files. This is done in a comparable way as the CDI and requires partners to configure the EDMED resp. CSR properties files. The Java Tool and XML formats for EDMED and CSR perform well in the present Sea-Search / SeaDataNet configuration and partners, having a local EDMED and/or CSR metadatabase, are encouraged to make use of these for submitting new or updated entries.

Incorporation of partner’s CDI XML files into the central CDI Metadirectory:

The partners must send their CDI XML files to the central CDI manager (i.c. MARIS). The Central CDI manager will perform global checks on the syntax (= technical format) and semantics (=use of codes, conformity to CDI libraries, conformity to field definitions) as part of its import procedure. Validated XML files will be incorporated in the central CDI metadatabase, that is available for querying by users via the CDI User Interface (http://seadatanet.maris2.nl/cdi/). Partners will receive a report on the import, including possible rejected records and their errors.

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