Australia New Zealand Land Information Council - ANZLIC Metadata Working Group
4 March 1999
The ANZMETA DTD v1.2 facilitates extension and customisation. Each geospatial data custodian can now define their own metadata extensions, which build upon the basic metadata that is required to form the directory level (Page 0 for the Australian Spatial Data Directory ASDD) metadata. This enables the definition of further metadata elements for custodian document management, applications to be automatically configured from the metadata, additional presentation information, and integrated directories.
The official references to the DTD are ...
The document that you are reading explains the extension capabilities, provides references to the controlled vocabularies (authority lists of valid values), and shows some worked examples. The previous ANZMETA DTD v1.1 documentation is still relevant for describing the structure and rules for each metadata element.
Custodians of geospatial metadata will need to define their own specific metadata elements (e.g. for private management purposes, for additional published information). Thematic directories will also require additional elements for their field of application (e.g. metadata to support WWW mapping layers).
However, each document collection must still meet the base level requirements for the ANZMETA DTD v1.1 (the Page 0 metadata for the ASDD). The new DTD has exactly the same structure and elements as the previous DTD, only now there are also configurable entities. This enables custodians to develop their own DTDs which reference, and extend, the ANZMETA DTD v1.2 to support their Page 1+ requirements. Their metadata can then serve multiple purposes - provide searchable content to the ASDD, meet their own metadata management requirements, provide additional information to searchers and applications, and provide additional metadata for interoperability with other directories.
Parameter entities have been added to various sections of the ANZMETA DTD to allow for local declaration of additional elements. This provides two ways to implement extensions (method 1 is recommended):
Certain other directories are already utilising these extension capabilities ...
If you find yourself trying to develop extended extended DTDs, then that probably indicates that some common elements need to be folded back into the higher-level DTDs. This can happen as a consultative process. Please discuss such issues on the OZMETA-L geospatial metadata listserver.
These entity sets allow you to use special characters in your XML documents. Well known examples are "<" to represent "<" and "&" to represent "&".
ANZMETA DTD v1.1 used HTML character entity sets which cannot be used with XML parsers. The following entity sets have been used with ANZMETA DTD v1.2 (ISOlat1, ISOgrk1, ISOpub, ISOtech).
See discussion about the use of Open Catalogs with your XML parser for entity management to resolve any external references.
The following authority lists can be defined in the "thesaurus" attribute of the <keyword> element. These lists allow validating parsers to also check the content of the keyword elements against the valid values from the relevant authority list. Metadata management systems and search interfaces can take advantage of this.
See further explanation about Thesauri for ANZMETA DTD.
Here are the controlled vocabularies for use with ANZMETA DTD ...
These examples are based on the example XML document from the ANZMETA v1.1 documentation.
Another release of the DTD will occur during 1999 in line with the review of the ANZLIC Metadata Guidelines. That will address any Page 0 issues and any common Page 1 requirements.
Please discuss such issues on the OZMETA-L geospatial metadata listserver.