ASDD documentation and resources

Modified: 2009-12-07

ASDD documentation and resources

This is a concise guide to the various documentation and resources that comprise the Australian Spatial Data Directory (ASDD). The areas of interest are:
Architecture and technologies | Metadata management | Z39.50 protocol | Organisations establish nodes

Architecture of the ASDD

Architecture and technologies - A brief description of technologies behind the ASDD. Explains each component. The architecture diagram shows how it all fits together.

The technical coordinating node of the ASDD is Geoscience Australia. Please contact Geoscience Australia with any ASDD problems, technical issues, or requests to add new nodes to the ASDD gateway interfaces. - ASDD manager asddupdate@ga.gov.au

Metadata management

Metadata - Data about data. A dataset description is a concise document (an XML instance) which explains a spatial dataset (i.e. a metadata record).
Official Standard: Core Metadata Elements for Land and Geographic Directories in Australia and New Zealand - The "ANZLIC Metadata Guidelines" which specify the allowable content and describe its use.
Official Standard: ANZMETA XML Document Type Definition (DTD) for geospatial metadata - Structural rules for representing ANZLIC metadata as documents in the eXtensible Markup Language (XML). Defines the metadata elements, and their order, structure, and relationships.
ISO 19115 Geographic Information - Metadata - This is an International Standard for spatial metadata.
Options for geospatial metadata management - Describes options for managing geospatial metadata. Metadata management systems need to be capable of exporting metadata records as valid XML documents as well as HTML and SUTRS format. (See requirements and standards.) You will send these to your local ASDD node manager, or you will use them to establish your own ASDD node.
Coordination - There is a metadata coordination representative for each State/Territory and the Australian Government. See the Metadata Working Group (AMWG).

XML metadata - Each dataset description is a concise summary document in the plain-text eXtensible Markup Language (XML). The document must comply with the structural rules defined by the ANZMETA XML Document Type Definition (DTD).
Controlled vocabularies - various authority lists for keywords and Geographic Extent Names.
Build upon ANZLIC metadata - The XML metadata can be extended to cater for additional metadata and for local data management. This capability starts with version 1.2
OASIS Catalog - A mechanism for your XML parser to find the local copies of Document Type Definitions (DTDs) and character entity sets.
Please discuss geospatial metadata and ASDD issues on the OZMETA-L geospatial metadata listserver and the ASDI-L listserver.
Validate your XML documents.
XML document validation tool.
A RELAX NG XSD is used by the validation tool to validate the content of anzmeta-1.3.dtd XML document instances that are compliant to the ANZLIC metadata guidelines version 2.0.

Z39.50 search and retrieve protocol

ASDD search and retrieve overview - Explains ASDD Z39.50 search, retrieve, and present.
General Z39.50 configuration issues - The GEO Profile, Z39.50 Attribute Sets, Record Syntaxes, Element Sets.
Official Standard: GEO Profile for Z39.50 - Defines how Z39.50 servers and clients conduct geospatial (hence GEO) search. The profile defines the many aspects of the search protocol, so as to enable consistent search and interoperability.
Official Standard: Z39.50 search and retrieve protocol (ISO 23950) - The Z39.50 Maintenance Agency provides vast resources and discussion groups for the evolution of the protocol.
Attribute Sets - Z39.50 way to specify many different aspects of the search and retrieve. Define which metadata attributes can be used for search (e.g. title, abstract, full-text), the possible relationship (e.g. >= or <=), the possible data structures (e.g. date, co-ordinate), etc.
Use Attribute - Z39.50 way to define the metadata fields to be used for search using a well-known mapping (e.g. 4=title, 62=author, 2040=northbc)
Element Set - Z39.50 way to define the metadata elements that are to be delivered.
Record Syntax - Z39.50 way to define the type of document to be presented, e.g. HTML, XML, SUTRS (plain-text).

See explanations of "node" and "gateway" below. Avoid confusion between these.
Node - a collection of metadata documents (a repository) which can be searched via a Z39.50 server. One organisation's server can provide search facilities for a number of nodes, e.g. the BRS server has the "com" and "anrdl" nodes.

Gateway - a search interface that connects the World Wide Web to the Z39.50 realm. A gateway allows WWW browsers to compose a search, translates it into Z39.50-speak, sends the search query to the distributed nodes, then collates and presents the results. The main ASDD gateway at Geoscience Australia is one example.

Architecture and technologies - A brief description of technologies behind the ASDD. Explains each component. The architecture diagram shows how it all fits together.
Build your own search interface - Any other HTTP-Z39.50 gateway can interrogate a set of the ASDD nodes. The Z39.50 connection details are available from each node description. The complete list is also available at /asdd/tech/serverstatus/serverlist.txt
Establish your own Z39.50 information server and node of the ASDD - See section below Organisations establish nodes
Integrating other directories - Explains how the ASDD and other networked directory systems can inter operate.

Organisations establish nodes

It is the responsibility of individual nodes to maintain their metadata in accordance with the relevant standards.

Requirements and Standards - Concise overview of the criteria for participation as a node of the ASDD.
Node Managers interface - For node managers to prepare their high-level node descriptions, and access various resources and log files. When a node manager intends to establish a new ASDD node they will describe it with a node description. This is a password controlled area for document preparation and access to various online services to assist with node management. (Note that this is *not* for metadata authors, see metadata management section above.)
Implementing new ASDD nodes - Detailed explanations about how to implement new nodes using various Z39.50 server software, including requirements, configuration and server options.
Establishing individual ASDD nodes - This high-level explanation shows how any organisation can participate. Provides "how to" dot points for setting up a server. Case studies show how some other organisations have done it and estimate resources that are involved.
Upgrading existing ASDD Isite nodes - Provides recent software and configuration files for Z39.50 servers that use Isite. Explains the upgrade procedure.

Testing your node - it is not sufficient to just install the software. You need to also ensure that it is properly configured and reliably answers all queries. It needs to automatically re-start when the machine reboots. You need to ensure that search queries from any host can reach your node (just like your web server, no firewall). Testing tools and strategies are dependent on your particular brand of Z39.50 server (Isite, MetaStar, Zebra). Please ensure proper configuration before asking for your node to be added to the ASDD gateways.
Testing Isite ASDD nodes - Provides some hints for testing your Z39.50 server.
You should monitor your own node for failures. If you do not, then the ASDD Status of Nodes application has an error log which might help a little (status-200912.err).
ASDD implementation overview - Provides a brief overview of how the ASDD operates and the current status of its implementation.
The quarterly reports will help you to improve your search service.

Australian Spatial Data Directory (ASDD)

ASDD Search

Architecture of the ASDD

Metadata Management

Z39.50 Protocol

Establish Nodes

ASDD documentation and resources

Architecture of the ASDD

Metadata management

Z39.50 search and retrieve protocol

Organisations establish nodes