Use of standard vocabulary services in validation of water resources data described in XML

The machine readable encoding language XML is used in water informatics to describe resources and observational data, such as the Water Data Transfer Format (WDTF). WDTF is part of an Australian initiative, established by the Australian Bureau of Meteorology in collaboration with CSIRO, to collate water resources data from multiple data providers into a national water information system. A common way of validating XML data is by defining a schema using XML Schema Definition language (XSD) and performing validation using standard XSD tools. However, XSD validation lacks the ability to perform content validation to assert context, domain and organizational rules such as soft-typing, co-constraints, and code-list or vocabulary checking, which is required in the validation of WDTF data. In this paper, we describe a validation service for validating water resources data encoded in WDTF, which combines structural and content validation. We also describe the use of a vocabulary service with the WDTF validation service to perform code-list and vocabulary checking.