Asynchronous Geospatial Processing: An Event-Driven Push-Based Architecture for the OGC Web Processing Service

Geospatial processing tasks like solar potential analyses or floodplain investigations within flood scenarios are often complex and deal with large amounts of data. If such analysis operations are performed in distributed web-based systems, technical capabilities are mostly not sufficient. Major shortcomings comprise the potentially long execution times and the vast amount of messaging overhead that arise from common poll-based approaches. To overcome these issues, an approach for an event-driven architecture for web-based geospatial processing is proposed within this article. First, this article presents a thorough qualitative discussion of different available technologies for push-based notifications. The aim of this discussion is to find the most suitable push-based messaging technologies for application with OGC Web Processing Services (WPS). Based on this, an event-driven architecture for asynchronous geospatial processing with the WPS is presented, building on the Web Socket Protocol as the transport protocol and the OGC Event Service as the message-oriented middleware. The proposed architecture allows pushing notifications to clients once a task has completed. This paradigm enables the efficient execution of web-based geospatial processing tasks as well as the integration of geographical analyses into event-driven real-time