Multiple Data Structures - All data managers will be aware of the problems caused by the diversity of data structures or formats and the variety of quality control checks carried out on marine data. Each scientist or each agency checks data using different techniques and often look for different errors depending on the intended use of the data.
Data Quality Standards - Data managers are faced with the dilemma of attempting to provide data of high quality to the user and balancing this with the time and effort required to check the data. In addition to this, data can be provided to the data centre in a range of different qualities. Also, data quality is a difficult issue to address since data that may be considered high quality by one user may be considered poor quality data by another. It is often dependent on the use to which that data is put.
Multi-Dimensional Data - The multidimensional nature of marine data further complicates the management process. Most information technology that exists today is built to support two-dimensional data since most business data is two-dimensional. Geographic Information Systems (GIS) only support 2 dimensional data effectively and it has long been recognised that marine data management technologies must be sophisticated. Dr. Leon Zann, in his Australian State of the Marine Environment Report suggested that “The information technologies required to collect, analysis, manage, visualise and disseminate marine data must provide capabilities that reflect the multidimensional nature of this environment”.
Existing or Legacy Systems - Most of the agencies and organisations that manage or use marine data for their work already have computing facilities supporting their activities. These systems have often been developed at considerable cost, sometimes for several million dollars. The creation of any new framework to support the management of marine data must take these existing systems into consideration. No agency will redesign their system simply to conform to international standards.
7. Building a Framework on Existing Technologies
There are a number of innovative technologies available today that go someway towards addressing the issues described above. However, these technologies have never been applied in a holistic way to support the marine data management issue. Scientists and marine data managers are applying some of these existing technologies to their activities with a degree of success but the marine data community has not yet combined them. The whole picture must be considered in order to create the Virtual Data Centre.
There are many technologies available to day that can be used to support this vision. Some of the more significant technologies include: -
･Relational database management systems, specifically those with extensions to handle spatial data such as Informix Universal Server, ORACLE 8, and IBM' s DB2;
･Capabilities of traditional GIS products such as ArcInfo and ArcView;
･Java software to increase accessibility of data systems via the internet,
･Object broker or middleware technologies such CORBA and Microsoft's Component Object Model,
･Spatially oriented application development environments such as provided by Formida,
･eXtensible Markup Language (XML),
･Data warehousing and data mining,
･Development of the Electronic Nautical Chart,
･Intelligent software agents,
･Image management and visualisation tools including IDL, PV-WAVE, ER Mapper.
