Tethys WPS Server: An open source platform for Water Resources Web Processing Services (WPS) development

Developing a complex environmental modelling web application or "web app" can be a daunting task that requires integration of various models and data sources with ever-changing Internet technologies. Service-oriented architecture (SOA) has been shown to be useful for building complex modelling workflows. However, compared with other types of web services such as those for data delivery and mapping, the implementation of Open Geospatial Consortium (OGC) web processing services (WPS) for environmental modelling and data analysis is not very common. Indeed, tools to simplify the development and deployment of WPS for general modelling cases are lacking. This paper presents the development and testing of a ready-to-use WPS implementation called Tethys WPS Server, which provides a formalized way to expose web app functionality(s) as standardized WPS in alongside an app's graphical user interfaces. The WPS server is created on Tethys Platform by leveraging PyWPS. A case study is provided to demonstrate how web app functionality(s) can be exposed as WPS using our open source package as well as show how these WPS can be coupled to build a complex-modelling web app. The primary advantages of Tethys WPS Server include (1) lowering the barrier to environmental WPS development and deployment, (2) providing web services-based access of apps, (3) improving web app interoperability and reusability, and (4) facilitating complex modelling implementation.