As a simple example, how many ways are there to record position using latitude and longitude? First there are degrees, minutes and seconds and then degrees, minutes and decimal minutes. There are possibly one or two variations of this. However, agreement could be reached relatively quickly on 3 or 4 variations of latitude, longitude based positions. Once agreement was reached, XML tags to describe and document these different methods of describing position can be developed.
The point of this example is to indicate that the marine data community could agree quite quickly on a series of tags to describe the many different parameters. The issue almost becomes one of semantics. The main difficulty is agreeing on the definition of each parameter. While this could take some time, there is a possibility that work already undertaken to support other purposes may provide a way ahead. As part of its work in developing formats, the IODE Group of Experts on Technical Aspects of Data Exchange (GE-TADE) have created an extensive parameter key word list that could be used to form the basis of the semantic description necessary for developing an XML library.
9.3 How Will an XML Based Framework Work
Two approaches are required in order to gain benefit from an XML based marine data framework. The first approach must take into consideration existing systems. To support these tools are needed that will automatically apply XML tags to data that has been extracted from a system to be exchanged. Other tools are also required to interpret (or parse) data that is received with XML tags and support the transfer of this data into the existing database system.
The second approach is the integration of XML technologies within new systems. Companies such as ORACLE are providing facilities to incorporate XML and XML based functions directly within the database environment. Tools are available to parse XML tagged data and automatically update databases. A Marine XML will build on and support these existing technologies.
9.4 What Are the Benefits of Using a Marine Version of XML?
The use of XML tags will solve one of the major problems confronting data centres today. Data centres have always had difficulty with the archival of data from multiple sources, in multiple formats. There is generally a compromise between the need to retain all the data fields in a data set and the need to convert the data to a format used by the systems in place in the data centre. Often fields included with a data set are lost because they are not present in the data centres internal data format and must be removed before added to the data centres system. XML can help with this. Data can be stored in the originator's format, including all ancillary fields. When it is necessary to merge the multiple data sets to create a single data set the relevant fields (as tagged by XML) are selected and retrieved. This process can also be applied when ‘sending’ data to analysis, visualisation and other applications.
