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International Archives of the Photogrammetry, Remote Sensing
2. | SENSORS
"In the next century, planet earth will don an electronic
skin. It will use the Internet as a scaffold to support and
transmit. sensations. This skin is already being stitched
together. lt consists of millions of embedded electronic
measuring devices: thermostats, pressure gauges, pollution
detectors, cameras, microphones, glucose sensors, EKGs,
electroencephalographs. These will probe and monitor cities
and endangered species, the atmosphere, our ships, highways
and fleets of trucks, our conversations, our bodies even our
dreams.” [3]
One of the important activities in the GIS domain is
data collection from the wanted area. Over the time many
attempts by the scientists in the world have been accomplished
to find the best way of data collection. One of these attempts
result led to invention of the new technology which called
sensor technology.
Using Sensors in many of the business have some
favorites for users, such as:
e Real-time Data Capturing: Sensors give organizations
the capability to receive real-time data and
information about a situation or environment,
wherever it is happening or located.
* Lead to Better Knowledge and Tracking throughout
the Supply Chain: Sensors embedded in objects will
enable manufacturers to increase their knowledge of
products at all stages through the supply chain, from
manufacturing to distribution to logistics.
* Lead to Consumer Trending: Wireless remote
sensing combined with other data such as economic
or market information can lead to useful trending of
consumer tastes and preferences. This will deliver
real-time customer insights while also providing
valuable information on product life cycles.
* Provide Basis for Simulation: One of the key aspects
of the Reality Online vision is a digital copy of an
environment, object or person. Sensors will be one
technology by which virtual doubles of environments
will be created.
* Spur the New Applications
In general we have two types of sensors: remote
Sensors, which measure physical properties at some distance
from the sensor and in-situ sensors, which measure a physical
property within the arca immediately surrounding the sensor
2].
Today, technological innovations have moved sensors
well beyond their original capability as simple, standalone
detection devices; they are now much more important than that.
By continuously connecting a variety of sensors through
wired/wireless connections, sensors are moving beyond
individual smart objects to more complex networks that will
enable people to "see" more of the physical world and act on it.
In fact, for some purposes, having a collection of
Sensors will be gratefully useful; a sensor collection can be in
three following types:
* Sensor Package: Composed of multiple sensors that
operate together to provide a collective observation
or related group of observations. For example, a
group of individual sensors that measure different
chemical species can be grouped as one sensor that
provides “water quality”.
1149
and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
e Sensor array: A set of sensors of the same type at
different locations.
e Sensor Web: Can be seen as a system composed of
multiple science instrumenUprocessor platforms that
are interconnected by means of a communications
fabric for the purpose of collecting measurements and
processing data for Earth or Space Science
objectives. The most unique feature of the sensor web
is that information gathered by one pod is shared and
used by other pods. While distributed sensors
networks only gather data, communicate and uplink
to a centre.
3. WEB SERVICE
A formal definition of a web service may be borrowed
from IBM's tutorial:
"Web services are a new breed of Web application.
They are self-contained, self-describing. modular applications
that can be published, located, and invoked across the Web.
Web services perform functions, which can be anything from
simple requests to complicated business processes...Once a
Web service is deployed, other applications (and other Web
services) can discover and invoke the deployed service. “
It is obvious from this statement that the industry vision
for Web Services perfectly correspond to the goal of designing
an interoperable architecture for data fusion, data analysis or
data sharing between different sensors/sensor webs. In such
architecture, a web service is like a bridge for access to data or
analysis tools of sensors/sensor webs which could be deployed
for different purposes (Figure 1).
Figure 1: General web service architecture
4. SENSOR COLLECTION SERVICE (SCS)
With the rising trend in using Internet, accessing to
environmental data via Internet has an important role in many
of environmental projects. Sensor Collection Service (SCS) is
introduced as a typical OpenGIS Consortium Geo Web Service
that deals with sensors and provides the user facilities to access
environmental sensor data through Internet. Clients
implementing SCS can also obtain information that describes
the associated sensors and platforms.
From viewpoint of implementation specification, SCS
provides at least two operations as interfaces for client to
interact with the service. The operations provide different
facilities. Two available operations supported by SCS are
GetCapabilities and GetObservation (Figure 2).
Figure 2: SCS as Service Provider, provides GetCapabilities
and GetObservation interfaces