Internet GIS Application Framework for Location-Based ...

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Jul 14, 2012 (5 years and 1 month ago)

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Internet GIS Application Framework for Location-Based Services
Development
Dragan Stojanovic, Slobodanka Djordjevic-Kajan
Faculty of Electronic Engineering, University of Nis
Beogradska 14, 18000 Nis,Yugoslavia
Email: {dragans, sdjordjevic}@elfak.ni.ac.yu
Abstract
Support of Internet GIS application framework for design and development of location based
services is described in this paper. Definition, main characteristics and functions of location-based
services are presented and the Internet GIS as their core component is described through overview
of possible architectures and development methodologies. The iSTOMM - a framework for Internet
GIS application development is introduced as the collection of spatio-temporal data modeling and
management tools and techniques for design and development of location-based services. The
power of spatio-temporal concepts incorporated within 3-tier information systems architecture of
iSTOMM have been verified through development of Yellow pages service, and remains under
further refinement and improvement through development of more sophisticated location based
services.
1. Introduction
The Internet and Web, on the turn of the Millennium, are tremendously changing every aspect of
our lives. Communication with business partners, commerce transactions, buying and selling goods
and services, sharing and exchanging ideas and information, learning, software development, and
many others everyday business and leisure activities we are forced to conduct using specialized
Internet/Web based information systems popularly named: e-business, e-commerce, e-learning, e-
medicine, e-everything, etc. The open infrastructure, the open and public standards and the
decentralised architecture are responsible for such success and penetration of Internet and Web
technology in human everyday life and business.
The exponential Internet growth and the global connectivity reached in the last few years have had a
great impact on the requirements of contemporary and next-generation information systems.
Fundamental characteristics include efficient data access, delivery over the Web, heterogeneity, and
interoperability. The primary focus of Internet/Web use for mass distribution and presentation of
public information has moved to distribution of software services over intranet, extranet and
Internet [1]. Next-generation information systems are going to be assembled of specialised Web
services (components) that are self-contained, self-describing, modular applications that can be
published, located and invoked across the Web using wide spectrum of Web-enabled stationary
(desktops, workstations, Web TV) and mobile devices (PDAs, mobile phones, laptops, handheld
computers, etc.). The Internet/Web technology wave has also reached the Geographic Information
Systems (GIS) research and development sector. The integration of GIS and Internet technologies is
allowing GIS developers to provide access to geo-information and processing without burdening
end users with complicated and expensive software and dedicated hardware. The recent
convergence of multiple information and communication technologies including Internet, wireless
communications, mobile position determination, portable Internet-enabled devices and GIS has
given rise to a new class of location based applications and services. Location based services deliver
geographic information and geo-processing power between mobile and/or static users via the
Internet and/or wireless network. Development of GIS, as integral components of location-based
services remains the complex task so the availability of Internet GIS application framework is
crucial to achieve greater scalability, reliability and fast-time-to-market.
The rest of the paper is organised as follows. Section 2 reviews main concepts and architecture of
location-based services and their main component - Internet GIS. Section 3 presents Internet GIS
application framework, giving the overview of spatio-temporal object model it is based on and
describing its architecture and functional components. Section 4 presents location based service for
Yellow pages, developed on top of Internet GIS application framework. Section 5 concludes this
paper and gives an overview of future research.
2. Internet GIS and Location Based Services
Over the last few years the GIS research and development sector has undertaken a paradigm shift
away from the pure desktop GIS solutions which has to be used only by experts giving results, often
on paper, to non-experts. Now, through the introduction of Internet or intranet/extranet-based GIS
systems, it is possible for any person to use some kind of GIS and mapping system. Only minimal
browser technology enable users to zoom into their data, explore and analyse it and produce a report
that can be pasted into any office application environment. Tomorrow's (or even today's) GIS
software "scene" will increasingly consist of data manipulation and spatial analysis tools designed
as Web-based components or applications, operating on geo-data in a distributed, Internet/Web-
based environment [2].
With the emergence of Internet/Web the design and development of contemporary and next-
generation information systems face new challenges, opportunities and requirements. The first
generation of Internet information systems was considered mostly static in nature, providing users
with poor and limited interactive view of information from databases, generated by Web servers.
The contemporary architecture of information systems is now distributed over multiple tiers
(usually: client, application and data server tiers), and assembled of application components that are
self-contained, self-describing, modular applications (services). Such components can be published,
located and invoked across the Web using computing devices of all sizes: from mainframes to
PDAs and mobile phones [3]. In accordance with it, there are two basic approaches to development
and deployment of GIS or any other complex, data-driven application on the Internet: as server-side
or client-side applications [4]. In a server-side Internet GIS application, a Web browser is used to
generate server requests and display the results. An Internet GIS server usually combines a standard
Web (HTTP) server and a GIS application server, and the GIS databases and functionality reside
completely on the server(s). Within server-side GIS application users interaction in Web browser
represents the request which is transferred to a Web server. The Web server passes the request to a
GIS application server, which runs GIS application software, generates a map graphic, converts the
graphic to Web format, wraps the image in HTML and sends it back to the Web server, which then
returns the response to the client as a standard Web page. Server-side applications can comply with
Internet standards, because the entire complex and proprietary software, as well as the GIS
databases reside on a server that's administered by the deploying organization. Disadvantages of
server-side solutions are primarily associated with poor performance and limited user interface and
interaction.
The future belongs to client-side, 3-tiers Internet GIS applications, especially for intranet and
extranet solutions dedicated to provide full GIS analysis and management support to specific users
within business, government or public utility sectors. In client-side Internet GIS, the client is
enhanced to support GIS operations, while the middle tier, representing by application server, is
populated with application logic (figure 1). In such systems either a substantial amount of GIS
functionality is moved to the client, or only the user interface is enhanced slightly to enable specific
user interaction. Depending on the degree of functionality possessed by the client, the OpenGIS has
developed a model to classify different types of Internet GISs according to their portrayal service
built within clients with various "thickness" [5]:
 Thin clients (only raster images JPG and PNG)
 Medium clients (graphic primitives WebCGM and SVG)
 Thick clients (data in the form of simple features XML/GML, processed at the client side)
Client-side solutions typically are implemented by augmenting the Web browser with Java applets,
ActiveX components or plug-ins. However, some client-side solutions require users to install a
complete client application. The primary advantages of client-side solutions are the abilities to
enhance user interfaces, improve performance and implement advanced solutions using both raster
and vector data.
Internet GIS client
Web browser
(ActiveX, plug-in,
Java applet)
or
GIS application
GIS data
Web
server
Client side programs
and data
(HTML, applets)
Internet GIS server
GIS application
server
GIS data
(DBMS, files, etc.)
Figure 1. Client-side Internet GIS architecture (3-tiers)
The main problems associated with client-side solutions relate to distributing software and data.
Distributing software (Java, ActiveX or any other type) is still problematic because of portability
and platform incompatibilities. Considering distribution of geo-data and geo-services, ISO TC 211
[6] and OpenGIS [5,7] are working on open standards for interoperability within geo-information
infrastructure, which have to be foundation of contemporary Internet based GISs. Their
standardisation activities and initiatives require consensus on geo-information aspects related to:
geometric model, description of geo-data sets and geo-services, access and query of metadata and
return of query results, selecting of geo-data and formatting (and transferring) geo-data sets' results.
The recent convergence of network computing and wireless telecommunications with Internet-
based spatial technologies is giving rise to a new class of location-based applications and services.
Location based services represent Internet GIS applications which, according to location of the user
(or some requested location), deliver geo-data and geo-processing from the GIS servers across
Internet/Web for using on wide spectrum of Web-enabled stationary and mobile devices [8]. The
value of location based services is in giving assistance to stationary and mobile users in day-to-day
situations such as giving the shortest route from their location to the nearest place of interest or
sending emergency service to their current location in the case of accident. The truth power of
location based services lays in delivering GIS functionality and location-based information across
fixed and mobile Internet-based networks, to be used by anyone, anywhere, at any time and on any
device.
Location is central to how people organize and relate to their world. Knowing the location of
people, objects, and phenomena at any time within end-user applications that are aware of the
position of a user, and delivered through a wide range of devices via the Internet and wireless
network, bring invaluable benefits to business, consumer and government sectors. According to
OpenGIS - OpenLS [9], location represents a position in space and time that can be measured and
whose coordinates can be derived in a particular spatial and temporal reference system. However, at
the current state of location based services technology, the temporal aspect of geographic location is
mainly neglected, or only partially integrated within recent research, development and
standardisation initiatives and solutions. That omission is inherited from a GIS community that
hasn't still explored and established the full potentials of managing temporal aspect of geo-
information [11].
The architecture of location based services consists of three main parts (figure 2) [9]:
 Positioning of mobile terminals based on either GSM/GPRS/UTMS mobile communication
systems, or GPS/GLONASS/Galileo satellite positioning systems.
 Wireless communication network based on GSM/GPRS/UTMS.
 Internet/Web GIS that provides spatio-temporal data and services over Web.
GIS
(Location)
Information
Server
Location
Data Sources
(DBMS, Files,)
GPS / GLONASS/ Galileo
positioning
Mobile
user
Wireless-IP Platform
PSTN
Positioning
server
(GMLC)
Internet
or
Intranet
Gateway
Services
Network
services
Network
Management
Control
GIS (Location)
application
server
DSL &
Cable
Location application
services
Stationary user
Location application
service clients
GSM / GPRS / UMTS
positioning
GIS
Location Information
Figure 2. Location based services concept and architecture (adapted from [7])
GIS (Location) Information Server provides access to location data sources distributed over
Internet, which possess different structure (DBMS, files, etc.) and are stored in different, proprietary
or open formats (SHP, MIF, XML, GML, GIF, PNG, etc). Location application services represent
application components integrated within GIS (Location) Application Servers that operate on
location content and provide value-added services to two main group of clients: wireless and wired.
Gateway Services enable integration of existing wireless-IP platforms maintained by mobile
communication operators with Location Application Servers and Location Service Clients. Such
clients operate either on fixed (desktop) or mobile terminals and interface directly with
users/customers, and depending on processing and graphic capabilities of targeted device possess
various levels of functionality and interactivity ("thickness").
Three generations of location based services is identified [10]. First generation services were
limited to stationary desktop computers with wired connection to Internet/Web and represent
currently mature Internet/Web GIS applications. They require the user to manually input his/her
location (or location of interest) in the form of a place name, street address, postal code, telephone
number and geographic coordinates and appropriate temporal information. Second generation
location services, which are available today, have the ability to determine rough locations typically
at the postal code level. Using a device such as the PalmVII to access the PalmNet data network, a
mobile user can find restaurants or gas stations in order of proximity or travel directions. Third
generation location services are more location aware, taking advantage of more precise positional
information and have the capability to initiate services proactively based on location. These trigger
mode services can notify the user of relevant events or conditions without the active participation of
the user such as traffic alerts that meet the user's preset preferences. Three types of triggers could be
identified:
 Object triggers notify the user of the mobile device when entering within a predefined distance
of a facility.
 Object-temporal triggers add the dimension of time.
 Affinity triggers allow one mobile device to know of the location of another mobile device.
Although considerable attention within location based service technology has been placed to its
constituent technologies, like wireless Web, mobile Internet-enabled devices and mobile
positioning, the heart of the whole system represents Internet-enabled GIS technology. Internet GIS
within location based services provides access to spatio-temporal information and GIS components
dedicated to its processing based on the location of user, or locations of mobile or static features
which are of interest to the user. The Internet GIS technology behind these services will empower
an increasingly diverse range of applications, putting even more valuable information and
processing in the hands of mobile and stationary users wherever and whenever it is needed. But, to
design and develop an Internet GIS application, to deploy it over multiple tiers within
wired/wireless Internet-based network and to provide and sell it to the end user as valuable location
based service, the developer must be supported by appropriate Internet GIS application framework
during all phases of development process.
3. iSTOMM - Internet GIS application framework
The ARGONAUT project at the Computer Graphics and GIS Lab, University of Nis, aims to develop
a suite of spatio-temporal data modeling and management technologies and tools integrated within
temporal GIS application framework - STOMM (Spatio-Temporal Object Modeling and
Management) [11]. STOMM is based on an object-oriented spatio-temporal data model and is
intended to support all stages of development process, from conceptual design through to
implementation, of a temporal GIS application. The STOMM data model was developed according
to specifications and standards developed within ISO/TC 211 [6, 12] and OpenGIS [7] related to
modeling and processing of geographic information. STOMM presents the successor of SPATEMP
system [13], but based on a new, STOMM data model, extended with more functionality in spatio-
temporal domain consistently with ongoing standardization and redesigned and redeveloped
according to component-based development approach. Based on this general framework, two
architecture-oriented application frameworks, for desktop and internet-based temporal GIS
applications (dSTOMM and iSTOMM respectively) have been implemented and have already
found valued, commercial purposes [16]. The primary purpose of iSTOMM framework is to add
significant GIS functionality to location based services developed around it. It provides a wide
variety of spatio-temporal services, which operate on spatio-temporal information arisen from
different information sources through Internet infrastructure and mobile terminal positions.
iSTOMM framework also provides support for displaying results of such operations to the mobile
or stationary Web terminals, in the form of maps, reports and messages and/or triggering specific
alerts and events.
3.1 STOMM data model
STOMM data model supports all important concepts found in object-oriented modeling theory and
paradigm, and can been used at conceptual and logical modeling levels. It is based on extensible
spatial and temporal class hierarchies. The basis of STOMM modeling framework is
GeographicObject class for modeling geographic features. The GeographicObject class represents
some entity or phenomenon of the real world, so it must have an actual or potential position in
space, which is represented by SpatialObject class, and time, which is represented by
TemporalObject class. STOMM data model enables user to design a temporal GIS application by
defining application specific classes representing the real-world entities (cities, forests, railways,
telecom cables) through inheritance of GeographicObject class or some of its subclasses already
designed for specific application domain. Spatial properties of geographic features are expressed by
their geometry, topology and cartographic presentation. In STOMM data model, spatial properties
are specified through SpatialObject class (figure 3).
+spatial property
GeographicObject
SpatialObject
Figure 3. GeographicObject class and its spatial property - SpatialObject class
The geometric description of a SpatialObject is defined through Geometry class (figure 4).
Considering Geometry class hierarchy, we have decided to accept standardization work pursued
within OpenGIS Consortium, concerning simple features and their geometries [7] and ISO/TC 211
work on spatial schema [6]. We have based our work on high correspondence between those
specifications relating to geometric properties of geographic features, differentiated mainly in the
level of abstraction. Our decision has also been supported by recent adoption of OpenGIS Simple
Feature Specification, by ISO/TC 211 in the form of Draft International Standard [12]. Geometry
classes contain appropriate descriptions of specific geometry through attributes (collection of points
represented different geometric primitives), as well as appropriate class methods representing
geometric and topological operations and relations. Coordinate values of geometric classes have
real world meaning within spatial referencing framework that has been provided through
SpatialReferenceSystem class associated to Geometry class.
Cartography
1..n
SpatialObject
1..n
Geometry
1..n
Figure 4. Cartographic presentation of spatial objects - Cartography class
Cartographic presentation of spatial objects and visualization of spatial objects' properties are
defined through Cartography class (figure 4). Thus, a clear separation between geometry and its
cartographic presentation has been defined. Cartography class contain attributes (symbols, font,
line width, colour, etc.) and operations that determine how properties of a given spatial object
(geometry and topology) are represented in terms of different parameters (scale, graphics output,
output media). Operations defined in the SpatialObject class for expressing topological relations,
direction relations and metric operators, define a foundation for definition and specification of
spatial part of spatio-temporal query language STOQL [14]. Temporal properties of features
modeled within STOMM data model are incorporated using TemporalObject class. TimeStamp
class hierarchy defines primitive temporal classes which can be used for timestamping: instant
(Instant class), period (Period class), and homogenous (MultiInstant and MultiPeriod classes) and
heterogeneous (TimeStampCollection class) collections of time stamps (figure 5). TimeStamp class
is associated to TemporalReferenceSytem class, which defines time type (UTC, GPS or arbitrary
time), and an offset from UTC time in hours and minutes. The TemporalObject class includes
operations for specifying temporal topology (before, after, during, meet, contain, etc.) and temporal
metrics (duration, union, intersection, difference, etc.) as defined in [11, 15]. These operations
represent the basis for definition and specification of temporal part of spatio-temporal query
language STOQL.
Instant
Period
MultiInstant
MultiPeriod
TemporalObject
TemporalReferenceSystem
TimeStamp
1..n
1..n
0..n0..n
TimeStampCollection
n
n
Figure 5. TemporalObject class and TimeStamp class hierarchy
The Evolution class is defined and associated to TemporalObject class (figure 6). Thus every
instance of specific temporal class, i.e. class inherited from TemporalObject class has the reference
to the appropriate Evolution class' object. An instance of Evolution class relates to an ordered set of
instances of TemporalObject class (its application specific subclasses) and those are the versions of
the same temporal object. The Evolution class, through its operations, provides evidence of
temporal object changes, records temporal object's lifespan, and provides reference to previous,
next, first, last, or the current version of a temporal object, as well as the versions valid at the
specific time stamp.
TemporalObject
Evolution
1
1..*
1
1..*
{ordered}
Figure 6. Evolution and TemporalObject classes
Classes of objects that are considered as temporal must be defined through inheritance of the
TemporalObject class. So, the methodology of temporal object modeling proposed here
corresponds to object timestamping by valid time. But, any attribute of such temporal class, which
possesses temporal behavior different from the rest of the class, could be modeled as a single
attribute of a separate class inherited from TemporalObject class. Thus, the temporal part of
STOMM data model can be considered as object-attribute timestamping. Geographic features
whose thematic (non-spatial) properties are changed through time are modeled as a
TGeographicObject class through multiple inheritance from classes TemporalObject and
GeographicObject (figure 7). Class TGeographicObject represents geographic features whose
thematic properties undergo changes through time, but whose spatial properties, specified in
SpatialObject class, are not changeable.
TemporalObject
GeographicObject
TGeographicObject
Figure 7. TGeographicObject class
In order to define spatial properties of geographic features, which are changed thorough time the
SpatioTemporalObject class is defined within STOMM data model, through inheritance of
SpatialObject class and TemporalObject class (figure 8). The SpatioTemporalObject class defines
spatio-temporal operations as an extended set of spatial operations defined in SpatialObject class,
with temporal information added in the list of operations' parameters. The topological and direction
operations can be twofold. One type of operations returns a boolean value indicating whether there
exists or not specific spatial relation at specific timestamp between spatio-temporal objects. The
other type returns the set of time intervals indicating that during these intervals spatio-temporal
objects satisfied specified relations. Metric operators simply specifies value of metric characteristics
(length, area, etc.) of spatio-temporal object at specified time instant, or a set of values for time
period or timestamp collection.
GeographicObject
TemporalObject
SpatioTemporalObject
SpatialObject
+spatial property
Figure 8. Modeling changes of spatial properties - SpatioTemporalObject class
Thus, within STOMM data model, four different types of geographic features can be modeled
according to their behavior in time, i.e. whether their spatial and/or thematic properties are changed
in time.
3.2 iSTOMM architecture and components
The iSTOMM architecture is compliant with the ISO/ODP 10746 guidelines for open distributed
systems, and adheres (as well as generic STOMM) to the standardisation work within OpenGIS and
ISO/TC 211, related to spatial data and services interoperability. Development of iSTOMM is based
on up-to-date Internet information technologies such as: Java, XML/GML, CORBA, etc.
iSTOMM application framework supports 3-tier Internet GIS architecture (figure 9), consisting of:
 Spatio-temporal information server;
 Spatio-temporal application server and application components;
 Spatio-temporal service client components.
Information & application
resources
(DBMSs, GIS, ERP,
CRM, other IS,)
iSTOMM spatio-temporal information server
iSTOMM client
(standalone or within Web browser)
STOMM data model
STOMM Extension
(user-defined classes)
iSTOMM application server
Intranet
Internet
Recordset/Resultset
i
STOMM Kernel
(Data management & integration)
Object-oriented implementation of STOMM data model (CORBA, EJB)
Internet
intranet
extranet
iSTOMM application components
(CORBA, EJB objects)
Web server
ODBC/JDBC
Query language
(
i
STOQL)
Visualisation &
animation

(
i
STOVAM)
)
Data conversion from/to STOMM
to/from XML, GML, VRML, etc.
S-T analysis, reasoning
& data mining
i
STOMM-based application client (CORBA & JavaBeans)
XML, GML, HTML, VRML, WML
(HTTP/WAP)
IIOP/ RMI
i
STOMM GUI components (CORBA & JavaBeans objects)
(Object-) relat ional DBMS
(Oracle, MS Access, SQL Server, mSQL,)

i
STOMM-based application components (CORBA, EJB)
Figure 9. iSTOMM architecture and components
The figure also shows appropriate information and distributed component technologies used for
implementation of iSTOMM components and communications between different components and
tiers. iSTOMM information server is based on implementation of STOMM data model within
commercial, relational, object-relational and object-oriented DBMS (Oracle 8i, SQL Server, MS
Access, etc.). iSTOMM application server consists of GIS application components, developed on
CORBA and EJB distributed component platforms, that represent building blocks of user
(application developer)-defined temporal GIS application. The main component of the iSTOMM
application server is iSTOMM kernel, which provides spatio-temporal object management and
integration, including mechanisms for updating, indexing, mediation & wrapping between different
data models, etc. iSTOMM application components represent software components for advanced
manipulation of spatio-temporal objects, such as:
 Processing of spatio-temporal-thematic queries, visually specified according to various spatial,
thematic and temporal criteria through visual spatio-temporal, object-oriented query language
iSTOQL;
 Visualisation and animation of spatio-temporal objects through iSTOVAM (iSTO Visualization
and Animation Manager);
 Conversion of spatio-temporal object from/to STOMM object format to/from XML/GML or
specific proprietary spatial data formats;
 Spatio-temporal analysis, reasoning and data mining (only generic support to appropriate, user-
defined components);
iSTOMM application server provides architecture extensibility enabling integration of user-defined
application components into its general architecture. Also mentioned components can be
customised, extended or replaced as long as the new components reside on the iSTOMM Kernel.
iSTOMM client contains GUI components providing access to iSTOMM application server
functionality, developed on JavaBeans and CORBA technology. Such components are integrated
with user-defined location based service client, executing within Web browser on mobile or
stationary user terminal or as a standalone application.
The main purpose of iSTOMM application framework represents design and development of
location based services for business, customer and government sector. Currently, two location-
based services based on iSTOMM are under development, and are intended for:
 Yellow pages directories;
 Vehicle navigation, tracking and guidance, which particularly exploits the full value of
iSTOMM temporal dimension.
4. Development of iSTOMM based "Yellow pages" service
The implementation of iSTOMM we've primarily based on contemporary, object-relational DBMSs
such as Oracle8i, which provides built in support for spatial data management, as well as
specification of user-defined data types. Also, by using JDBC/ODBC standards the access to other
commercially available DBMSs is provided. Implementation of iSTOMM application components
is based on Java programming language, as well as CORBA and EJB distributed computing
platforms. iSTOMM client GUI components are implemented either as CORBA clients or
JavaBeans components.
As the proof of the concepts built in iSTOMM application framework, we've developed a prototype
location based service for Yellow pages for city of Nis and its surrounding. Due to limited mobile
communication infrastructure that is provided by Yugoslav mobile operators, and unavailability of
mobile positioning services within their centers, we base our location based service on wired
Internet access. The Yellow pages application is based on geographic and thematic data collected
within GinisWeb prototype [17] representing city streets and street numbers, as well as different
types of business and public organisations (schools, bus and train stations, faculties, cultural
institutions and city government institutions). The background for vector-type graphical information
and visual context for user are provided through mosaic of GIF images of Nis City plan. Collected
spatial and thematic data about Nis places of interest is stored and organised within Oracle8i
database, using Oracle8i Spatial and interMedia, by implementation of STOMM data model as
Oracle database schema.
Since the usage of services is limited to stationary Internet GIS client within desktop Web browser,
the users location can not be specified by the known location of user's mobile terminal, which
could be determined by a mobile positioning server. The hypothetical location of user or the
location where he/she intend to be are specified within Yellow pages client in the form of some
kind of location determination information. Such location information includes street address and
number, telephone number, closest well-known city object, or geographic coordinates (included for
easy integration and usage of future GPS or GSM based mobile positioning services), and is
specified as input parameters to the services. Depending on the service needed, the users must also
specify request parameters for the business, government or public organisation they are seeking.
User request can be twofold: in the form of the type and/or nature of the closest organisation that
he/she is attempting to find or as name, phone number, or some other unique and known identifier
of such organisation. Next, a search for the desired business is executed by the iSTOQL component
against the iSTOMM Information Server that contains geographic and thematic content for Yellow
Pages. This server returns the location of the business that best matches the criteria specified in the
request. Using the appropriate location service client executing within Web browser, the location of
the business is then displayed on a map, relative to the hypothetical or desirable user location. The
user can determine and display the best and/or shortest route to the business, government or public
object of interest, or display particular thematic information connected to that organisation, such as
opening hours, telephone or fax numbers, and so on. With the provision of mobile positioning
services by mobile operators and wider usage of mobile Internet-enabled computing devices, the
iSTOMM based Yellow pages service will be easily extended to the wireless domain.
5. Conclusions and future work
Our further research goals are to enable and improve integration and chaining of iSTOMM-based
location based services with Web services, location-based or not, available through Web
infrastructure, in order to give much more value to the single service. To achieve this goal
iSTOMM based location service components must be designed and developed as self-contained,
self-describing, modular application components that can be published, located and invoked across
the Web through SOAP protocol. Such Web services based on spatio-temporal information must be
described using WSDL, and advertised within UDDI [18], of course when such standards become
mature enough.
Thus, the future developments of iSTOMM application framework intend to enable intelligent
integration of administrative, business, transport, cultural, leisure, information and application
services (Web services), as well as appropriate e-commerce-based services for purchasing, booking
and payment of previous ones, all through standard interfaces and service catalogs. Further
developments will also remain to follow standardisation guidelines and achievements of OpenGIS
and ISO/TC211, as well as initiatives of OpenLS, MAGIC, LIF and other international or industry
standardisation organizations dedicated to location based services. And, of course, many useful
location based Web services based on iSTOMM framework are going to be developed, deployed
and provided for public access in the near future.
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th
ICA/ACI 1999
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Temporal Data to Enhance Telecom Network Planning and Development", accepted for 3
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Portugal, 7-10 July 2001.
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