SENSOR WEB AND GEOSWIFT - AN OPEN GEOSPATIAL SENSING SERVICE 
S.H.L. Liang, V. Tao, A. Croitoru 
GeolCT Lab, Department of Earth and Space Science and Engineering, 4700 Keele Street, Toronto, M3J 1P3 
CANADA - (liang, tao, arie)@yorku.ca 
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KEY WORDS: Sensor, GIS, Web-based, Fusion, Monitoring, Environment, Internet/Web 
ABSTRACT: 
Sensor Web is a Web-centric, open, interconnected, intelligent and dynamic network of sensors that performs extensive spatial- 
temporal monitoring of our environment through coordinated work between multiple types and numbers of sensor networks. With 
the presence of cheaper, miniature and smart sensors; high-resolution remote sensing sensors; abundant fast and ubiquitous 
computing devices; wireless and mobile communication networks; and autonomous and intelligent software agents, the Sensor Web 
has become a clear technological trend in geospatial data collection, fusion and distribution. 
The concept of Sensor Web is new and exciting. Research in Sensor Web is still in its infant stage and several technical issues still 
remain to be resolved. One of the challenges is to fast deploy intelligent and coordinated sensors into field, perform on-demand 
sensing, and timely distribute observations through an open distributed GlService for informed decision making. At GeoICT Lab of 
York University, We are developing an open geospatial information infrastructure for Sensor Web — GeoSWIFT (Geospatial Sensor 
Web Information Fusion Technology), which serves as a gateway that integrates and fuses observations from heterogeneous spatial 
enabled sensors. We are also developing a Sensor Web which composed by a group of matchbox-sized wireless sensor nodes and 
can be fast deployed by simply spreading those tiny nodes in the field. By integrating the Sensor Web and GeoSWIFT, the goal of 
fast on-demand sensing for better informed decision can be achieved. This paper first reviews Sensor Web technology and its 
implication for GIS. Then we introduce the components and architecture of GeoICT Lab's developing Sensor Web. | GeoSWIFT, 
which is built on the OpenGIS standards, XML messaging technology, and its prototype are described in this paper. The examples 
of this integrated Sensor Web and GeoSWIFT in real-time weather information, earthquake information system, and traffic web 
cams are also presented in this paper. 
1. SENSOR WEB Business | Week(Gross, 1999) provided a vivid and 
understandable description of the sensor web: 
1.1 What is the Sensor Web? 
“In the next century, planet Earth will don an electronic skin. It 
The term ‘sensor web’ (SW) was first proposed by the NASA wil] use the Internet as a scaffold to support and transmit 
Sensor Web Applied Research Planning Group. In 2001, sensations, The skin is already being stitched together. It 
NASA provided a definition of a Sensor Web as follows (Delin consists of millions of embedded electronic measuring devices: 
and Jackson, 2001): thermostats, pressure gauges, pollution detectors, cameras, 
microphones, glucose sensors, EKGs, electroencephalographs. 
“A Sensor Web is a system of intra-communicating spatially ^ pese will probe and monitor cities and endangered species, the 
distributed sensor pods that can be deployed to monitor and atmosphere, our ships, highways and fleets of trucks, our 
explore new environments." conversations, our bodies — even our dreams." 
This definition by NASA has limited the sensor web to a small 1.2 Characteristics of Sensor Web 
scope in that is focuses on using only certain sensing 
instruments (sensor pods). The DoD also has a similar initiative 1.2.1 Interoperable 
called ‘Smart Sensor Web’, however, this focuses on tactical ^ The Sensor Web is achieved by connecting the distributed and 
battlefield operations. It is argued here that the definition of the heterogeneous in-situ and remote sensors by open, 
sensor web should take on a broader scope and vision, and that interconnected networks to an information centre that stores, 
the applications should not be limited to environmental disseminates, exchanges, manages, displays and analyzes the 
exploration or defense purposes. As sensing technologies, sensing information. Interoperability is the key to integrating 
network technologies, and computing technologies advance, all of these components and to achieving the vision of the 
similar concepts or definitions can also be found in different sensor web. 
research communities using different terminologies. Those 
terminologies, such as pervasive computing(Estrin et al., 2002), 1.2.2 Intelligent 
wireless sensor networks(Correal and Patwari, 2001), embedded ^ As computing technologies advance, computing resources have 
sensing, distributed sensor networks, scalable information ^ become seamlessly embedded into our daily lives. Intelligence 
networks and next generation remote sensing system, partially ^ can reside in all components of the sensor web by utilizing the 
touch on similar concepts. At the GeoICT Lab, we seek to ubiquitous processing capability. Another level of intelligence 
broaden this scope and include a wide range of sensors and of the sensor web will stem from connectivity among sensors; a 
applications into the definition of the sensor web. We found ^ concept that is analogous to human intelligence stemming from 
the connection of neurons in the brain.(Koch and Laurent, 1999) 
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