Open Geospatial Consortium (OGC)

The OGC is defined on their website as “an international industry consortium of 476 companies, government agencies and universities participating in a consensus process to develop publicly available interface standards. OGC® Standards support interoperable solutions that ‘geo-enable’ the Web, wireless and location-based services and mainstream IT. The standards empower technology developers to make complex spatial information and services accessible and useful with all kinds of applications” [128]. Aside from membership, the OGC publish technical specifications and best practice papers which are freely downloadable from their portal by the general public. The OGC’s offerings include OpenGIS® standards, SensorML, Web Services (OWS) and SWE specifications.

There are hundreds of millions of Internet-connected sensors on, in and around the Earth, and the number is growing rapidly. Standardization is the key requirement for communicating information about sensors and sensor data and for comparing and combining information from different sensors. The OGC’s Sensor Web Enablement (SWE) standards meet this requirement in the most complex as well as very simple applications. Sensor location is usually a key piece of sensor or sensor data information, and SWE standards make it easy to integrate this information into thousands of geospatial applications that implement the OGC’s other standards [129].

BT Research became an associate member of the OGC in 2007 as recommended by the author. Membership enabled participation in key initiatives, such as SWE. Leading members of OGC include familiar BT partners, such as Oracle, MIT, and UCL. Other notable international members are; NASA, ESA, Boeing, BAE Systems (aviation and defence), Google, Autodesk (2D & 3D design, digital content creation), MapInfo (GIS), ESRI, Intergraph (security, government, military, and industry),

Hitachi, Mitsubishi, University of Nottingham (Centre for Geospatial Science), University of Leeds, IEEE, GRSS, eSpatial, GeoConnections, Ionic, NCAR, Autodesk [130].

SWE Common

SWE Common is a way of describing structure and encoding of data, i.e. “self-describing” datasets. It allows for data in encodings other than XML (ASCII / Binary), e.g. to reduce bandwidth when transmitting video. It provides semantics for data elements by referencing dictionaries such as definitions provided by external dictionaries or ontologies can be used for (describing and encoding) streaming and multiplexed data [131]. SWE Common was created by Dr. Michael Botts and Alexandre Robin at the University of Alabama in Huntsville in 2003-2004. Inspired by the early work of Simon Cox on Observation and Measurements, SWE Common became a standalone SWE component during OWS-3 in 2005. It is used within multiple parts of the SWE framework (e.g. SensorML, O&M, SPS, SOS, SAS) [132].

Sensor and Process description language is very generic and uses SWE Common:

 Mixture of hard/soft-typed approaches;

 Enables description of structure;

 Encodes values independently;

 Allows for referenced and inline data [133].

OGC Web Services Phase 8 (OWS-8)

The latest OWS-8 demonstration video explains that the OGC interoperability program promotes OpenGIS Standards. The ongoing futuristic videos focus on geospatial data, Web connected sensors and open interfaces demonstrate the scenarios where OGC standards may be implemented. As stated in the narrative, “Lives and property depend on information flowing smoothly from one system to another. Most of the information is geospatial. It’s all about location, place and time” [134]. Furthermore, Geographical Information Systems (GIS), earth images, GPS tracking and other geospatial data and services can now plug into the World Wide Web through open interfaces, thus enabling diverse systems to interconnect and greatly improving the following:

 Data discovery;

 Information integration;

 Situational awareness;

 Decision support.

OGC OpenGIS services

Most of the OGC standards depend on a generalised architecture captured in a set of documents collectively called the Abstract Specification, which describes a basic data model for representing geographic features. Atop the Abstract Specification members have developed and continue to develop a growing number of specifications, or standards to serve specific needs for interoperable location and geospatial technology, including GIS. As illustrated in Figure 34, the OGC mainly focuses on earth

observation standards and GIS satellite imaging specifications, which feature high resolution vector images, and may be overlaid to create a rich representation or hybrid view of real-world information

[135].

Figure 34 - Relationship between Clients/Servers and OGC Protocols [136]

By means of traditional services of the OGC you can request sensor data, but only in a limited manner: 1. A map of the air temperature can be requested from a Web Map Service (WMS) for a certain

area of interest and point in time;

2. Raster data like satellite images or results of dispersion models can be accessed via the Web Coverage Service (WCS);

3. Vector data, say way points from vehicle tracking might be provided by a Web Feature Service (WFS).

However, a generic framework for sensor data integration into Spatial Data Infrastructures (SDI) was missing. Thus it was imperative to extend the SDI specifications by a framework for integrating sensors into SDIs. Therefore, the OGC founded the SWE initiative to develop specifications for access to and control of sensors and WSNs via the Internet [137].

Outside of the home, the location-aware capabilities of WSNs are suitable for a diverse collection of consumer-related activities, including tourism and shopping. In these applications, location can be used

to provide context-specific information to the consumer. …the tourism guide, the user is provided only information relevant to his present view; …the shopping guide, the user is provided with information relevant to the products before him, including sale items and special discounts and offers. Therefore, a kind of augmented reality is possible [138].