Implementing controlled vocabularies and international standards in web services to promote data interoperability: A case study

Ocean Networks Canada (ONC) is a not-for-profit society that operates and manages innovative cabled observatories which supply continuous power and Internet connectivity to scientific instruments located in coastal, deep-ocean, and Arctic environments. The data from the instruments are archived, quality-controlled, and made freely available to researchers, educators, and the public. The Oceans 2.0 data management system currently contains over 500 terabytes of data collected over 11 years from thousands of sensors. In order to facilitate access to the data, particularly for large datasets and long-time series of high-resolution data, a project was started in 2016 create a comprehensive Application Programming Interface (API) to provide programmatic access to all ONC data products. Interoperability and support for international data exchange are key factors in the requirements and design of the Oceans 2.0 API. In this paper, we discuss how these considerations were taken into account in the requirements and design of the Oceans 2.0 API. In particular, we discuss the 1) the use of controlled vocabularies; 2) support for international web service standards; 3) open data formats for delivery; and 4) common metadata standards. We present our findings as a case study examining the complexity of designing a multi-user, multi-standard system which attempts to strike a balance between usability and support for as wide a user-base as possible.