Geospatial Service Interfaces and Encodings for Mobile Applications

Abstract

Sensor Web Enablement suite (OGC SWE) offers a set of standardized service interfaces and data models which can be used for encapsulation of arbitrary observation-generating processes. In the past, AIT has used the OGC SWE for wrapping of hardware sensors, sensor data stores, cadastres and various sensor-like models behind OGC Sensor Observation Service (for data access) and Sensor Planning Service (for process control) interfaces. This approach was successfully applied in different projects (SANY, SUDPLAN), and resulted in development of the SOS and SPS service interfaces for the set of open source tools for time-series handling (ts-toolbox.ait.ac.at) developed by AIT. We have also discovered several issues and limitations of the OGC SWE services: (1) encoding of observations in SensorML/SWE Common is not always straightforward; (2) XML encoding/decoding can become extremely inefficient for large data sets; and (3) the complexity of the OGC XML schemas (O&M, SWE common, GML) further slows down the SWE-based solutions. However, these issues appeared of secondary importance compared to benefits of interoperability for classic environmental applications where both server and the client had plenty of memory and CPU power, the observations and processes creating them are well-defined and do not often change, and the interoperability across different organizations is a must. Recently, our focus moved towards Volunteered Geographic Information, and the rules of the game changed, with (potential) numbers and profiles of users and “sensors” drastically rising, and smartphones replacing the classical PCs as key client platform. This resulted in development of a Mobile Data Acquisition Framework (MDAF) which will be described in this paper.