Although the adoption of OGC Web Services for server, desktop and web applications has been successful, its penetration in mobile devices has been slow. One of the main reasons is the performance problems associated with XML processing as it consumes a lot of memory and processing time, which are scarce resources in a mobile device. In this paper we propose an algorithm to generate efficient code for XML data binding for mobile SOS-based applications. The algorithm take advantage of the fact that individual implementations use only some portions of the standards' schemas, which allows the simplification of large XML schema sets in an application-specific manner by using a subset of XML instance files conforming to these schemas.Comment: 9 pages, 2 tables, 7 figure

The number of Sensor Observation Service (SOS) instances available online has been increasing in the last few years. The SOS specification standardises interfaces and data formats for exchanging sensor-related information between information providers and consumers. SOS in conjunction with other specifications in the Sensor Web Enablement initiative, attempts to realise the Sensor Web vision, a worldwide system where sensor networks of any kind are interconnected. In this paper we present an empirical study of actual instances of servers implementing SOS. The study focuses mostly in which parts of the specification are more frequently included in real implementations, and how exchanged messages follows the structure defined by XML Schema files. Our findings can be of practical use when implementing servers and clients based on the SOS specification, as they can be optimized for common scenarios. 2 http://204.115.180.244/server.php 3 http://81.29.75.200:8080/oscar/sos 4 http://ak.aoos.org/ows/sos.php 5 http://bdesgraph.brgm.fr/swe-kit-service-ades-1.0.0/REST/sos 6 23 http://oos.soest.hawaii.edu/oostethys/sos 24 http://opendap.co-ops.nos.noaa.gov/ioos-dif-sos/SOS 25 http://rtmm2.nsstc.nasa.gov/SOS/footprint 26 http://rtmm2.nsstc.nasa.gov/SOS/nadir 27 http://sccoos-obs0.ucsd.edu/sos/server.php 28 http://sdf.ndbc.noaa.gov/sos/server.php 29 http://sensor.compusult.net:8080/SOSWEB/GetCapabilitiesGFM 30 http://sensorweb.cse.unt.edu:8080/teo/sos 31 http://sensorweb.dlz-it-bvbs.bund.de/PegelOnlineSOS/sos 32 http://sos-ws.tamu.edu/tethys/tabs 33

Although smartphone applications represent the most typical data consumer tool from the citizen perspective in environmental applications, they can also be used for in-situ data collection and production in varied scenarios, such as geological sciences and biodiversity. The use of standard protocols, such as SWE, to exchange information between smartphones and sensor infrastructures brings benefits such as interoperability and scalability, but their reliance on XML is a potential problem when large volumes of data are transferred, due to limited bandwidth and processing capabilities on mobile phones. In this article we present a performance analysis about the use of SWE standards in smartphone applications to consume and produce environmental sensor data, analysing to what extent the performance problems related to XML can be alleviated by using alternative uncompressed and compressed formats.

XML Schema is the language used to define the structure of messages exchanged between OGC-based web service clients and providers. The size of these schemas has been growing with time, reaching a state that makes its understanding and effective application a hard task. A first step to cope with this situation is to provide different ways to measure the complexity of the schemas. In this regard, we present in this paper an analysis of the complexity of XML schemas in OGC web services. We use a group of metrics found in the literature and introduce new metrics to measure size and/or complexity of these schemas. The use of adequate metrics allows us to quantify the complexity, quality and other properties of the schemas, which can be very useful in different scenarios.

Recent distributed computing trends advocate the use of Representational State Transfer (REST) to alleviate the inherent complexity of the Web services standards in building service-oriented web applications. In this paper we focus on the particular case of geospatial services interfaced by the OGC Web Processing Service (WPS) specification in order to assess whether WPS-based geospatial services can be viewed from the architectural principles exposed in REST. Our concluding remarks suggest that the adoption of REST principles, to specially harness the built-in mechanisms of the HTTP application protocol, may be beneficial in scenarios where ad hoc composition of geoprocessing services are required, common for most non-expert users of geospatial information infrastructures.