Tasmania’s land information holdings represent a considerable resource for government, the community and the private sector. They also represent a considerable investment on the part of the State. To ensure that this resource is used to its full potential, and for the benefit of the people of Tasmania, it is vital that all potential users are aware of the range of information that is available. This involves two key components, metadata for each data set, and a directory system for managing and searching this metadata.
What is Metadata
Metadata is data about data. It describes the content, quality, currency and availability of data. Metadata for land information provides:
The Tasmanian Land Information Coordination Committee (LICC) identifies access to land information as one of its key objectives. Through the Land Information System Tasmania (The LIST), the LICC has established the Tasmanian Spatial Data Directory (TSDD) as a key strategy to deliver on this objective.
In addition to meeting Tasmania's internal requirements, the TSDD is a node on a distributed Australian Spatial Data Directory, which has been established by the Australian and New Zealand Land Information Council (ANZLIC). This is part of that Council's implementation of an Australian Spatial Data Infrastructure (ASDI).
The TSDD is also a part of a broader State requirement to enhance access to, and knowledge of information. There are activities across government to improve the identification and indexing of the State's significant information resources and the TSDD will eventually be a component of this all-encompassing system.
For spatial data, the TSDD provides an interface for metadata entry and maintenance, as well as a search interface. Management of the metadata is based on the custodian concept, which has been adopted by the LICC for all spatial data management. It is up to the custodian to ensure that a TSDD entry exists for each data set for which they have custodial responsibility, and that this entry is current and accurate. Each custodian is issued with a login to the system, and through this, is restricted to adding/modifying records for which they have responsibility.
Tasmanian Spatial Data Directory and Spatial Data Set Metadata Policy
In developing an approach to the management of spatial data in Tasmania, the LICC has adopted the following policies:
Implementation of the TSDD
The TSDD has been implemented through an Oracle database and web based interfaces. The database resides on The LIST Delivery Server within ILS. Access for data entry and maintenance is managed through a forms based Internet interface which is accessible to any user who has a valid login. This interface is fully functional at Version 5.1 of MS Internet Explorer, however users of other browsers may experience problems. The interface can also be used to conduct searches, and the Export facility provides a means by which the data can be extracted into either a text file, html format or ANZLIC compliant XML format. This facility enables the user to save the files to a user specified disk.
The administration of the TSDD is managed by the Client Services Group within ILS. Details of the contact for requesting logins and assistance are provided on the home page for the TSDD.
Because the Australian Spatial Data Directory adopts a different data access approach, nightly extracts are made from the TSDD Oracle database to a Z39 web server. These extracts are then available to any user searching the ASDD the following day. A custodian can choose to delay release of certain records through a release field in the TSDD. This should ensure that only complete and verified records are accessible through the ASDD.
The ASDD then forms the standard interface for users wishing to identify spatial data about Tasmania. Through this interface the user can restrict their search to the Tasmanian Node or select from any combination of ASDD nodes. Once a record is selected the full metadata listing is presented in an html form. This can then be saved to disk or printed using standard browser functions.
Another alternative for accessing metadata about specific data sets is through the Australian Coastal Atlas. This atlas (also accessible through The LIST home page) enables the listing of metadata for any selected data layer. It is intended to include this option in the Enhanced Map Display of The LIST in the near future.
The diagrams below depict
the various means of identifying Tasmanian spatial data and associated
metadata, and the physical environment.
Options for identifying
spatial data sets and viewing associated metadata
Storage of data in the TSDD