Jonathan Yu

SISSVoc: A Linked Data API for access to SKOS vocabularies

The Spatial Information Services Stack Vocabulary Service (SISSVoc) is a Linked Data API for accessing published vocabularies. SISSVoc provides a RESTful interface via a set of URI patterns that are aligned with SKOS. These provide a standard web interface for any vocabulary which uses SKOS classes and properties. The SISSVoc implementation provides web pages for human users, and machine-readable resources for client applications (in RDF, JSON, and XML). SISSVoc is imple- mented using a Linked Data API facade over a SPARQL endpoint. This approach streamlines the configuration of content ne- gotiation, styling, query construction and dispatching. SISSVoc is being used in a number of projects, mainly in the environ- mental sciences, where controlled vocabularies are used to support cross-domain and interdisciplinary interoperability. SISSVoc simplifies access to vocabularies for end users, and provides a web API to support vocabulary applications.

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.

Towards Linked Data Conventions for Delivery of Environmental Data Using netCDF

netCDF is a well-known and widely used format to exchange array-oriented scientific data such as grids and time-series. We describe a new convention for encoding netCDF based on Linked Data principles called netCDF-LD. netCDF-LD allows metadata elements, given as string values in current netCDF files, to be given as Linked Data objects. netCDF-LD allows precise semantics to be used for elements and expands the type options beyond lists of controlled terms. Using Uniform Resource Identifiers (URIs) for elements allows them to refer to other Linked Data resources for their type and descriptions. This enables improved data discovery through a generic mechanism for element type identification and adds element type expandability to new Linked Data resources as they become available. By following patterns already established for extending existing formats, netCDF-LD applications can take advantage of existing software for processing Linked Data and supporting more effective data discovery and integration across systems.

Validating observation data in WaterML 2.0

Water observation data is a key element of a water resources information system as it is commonly used in national reports, environmental impact assessments and other analysis or modeling applications. A data standard is vital to support replication, synchronization and delivery for these applications. An international standard encoding for transfer of water information (WaterML 2.0) was previously developed to support data transfer requirements at all phases of the ingestion, data fusion, and delivery process, and suitable for adoption internationally by the water data community. Here we report on the design and implementation of a WaterML 2.0 validation service for executing specific schematic and semantic rules of the WaterML 2.0 standard. A WaterML 2.0 validation service allows for WaterML 2.0 encoded data to be tested in a context-sensitive manner. The OGC standard for Modular Specifications has been used for the WaterML 2.0 specification and includes a set of requirements and conformance classes. We report on how the set of requirements and conformance classes relate directly to the validation of WaterML 2.0 XML encodings. The result of a validation run allows users to determine the level of conformance of the respective WaterML 2.0 encoded data against the WaterML 2.0 specification. We also highlight the use of vocabulary services with the WaterML 2.0 validation service to perform code-list content and vocabulary checking. Design and implementation of a WaterML 2.0 validation service is presented.WaterML 2.0 validation service provides online testing of WaterML 2.0 data.WaterML 2.0 validation service features OGC vocabulary and code-list checking.Conformance levels can be tested against the WaterML 2.0 specification.