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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
and to provide a complex product to fulfil a client demand. The
GSI broker will serves as the mechanism supporting the
searching for products by users, the selection of partners and
the creation and control of the workflow [1], [5], [6].
Table 1: OGC service taxonomy
Service Categories
Human Interaction
Information Management
Workflow
Processing
Communication
System Management
Following the OCG service taxonomy categories (Table 1) [10],
the broker will support the workflow with additional
capabilities for control and management that can be placed into
the System Management OGC categories [11]. The main
components of the GSI architecture are the user (client), the
broker and the GSI nodes, arranged in client/server architecture
using Internet as the network environment (see Figure 2). The
client (organisation) is one of the GSP nodes, looking for
partnership to fulfill a demand. The client defines the objective
of the VE to be created, organises and looks for partners. The
client designs, implements, operates and owns the service via
the service broker, which will link the participating enterprises.
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Figure 2. GSI Enterprise Conceptual Architecture
The service broker supports the creation, execution, control and
management of business virtual processes. It is composed of:
e User Interface: gives access to the different services
provided in the broker:
e Search Engine: This service allows users to find the
business services they need. To find individual products
or services the search engine has access to the Workflow
Services Catalogue;
e Workflow Services Catalogue: in a virtual environment,
enterprises advertise their services in this component. It
should contain the business services definition (which
includes simple services like data supply) and the
197
workflow definition. This functionality can be inside or
outside the broker and is represented by a dashed line;
* Workflow definition tool: provides tools to define a
virtual business process made up of building blocks from
the workflow services catalogue (chaining enabler),
which is feed by the enterprises participating in the GSI.
The workflow definition tool creates a single definition of
the virtual business process, facilitating its enactment:
e Workflow rule engine: the full virtual business process
definition will be passed to the workflow rule engine for
enactment and control of the execution. It communicates
with the WFMS of the GSI nodes to trigger the activities
when corresponding. However, the participating nodes
not necessarily need to own a WFMS in which case the
trigger to start the process is not automated. The
enactment service of the workflow engine takes care of
security mechanisms for data transmission over the
network;
* Administration and control tool: it is responsible for
keeping track of the progress made in the execution of the
virtual business process, provides status of all active
components in the system and keeps a log history file
with performance data like duration of the activities, that
can be consulted by the membership organisations
participating in the GSI via the user interface.
6. CASE STUDY: IMPLEMENTATION OF
THE ‘VIRTUAL’ LAND AGENCY
The Egyptian Government has the need of a modern Land In-
formation System (LIS) to improve Local Real Estate market
and encourage foreign investments as some of the main reasons.
The tasks and data needed for the LIS are distributed in three
different organizations from the government:
e The Egyptian Survey Authority in charge of the rural an
urban parcel surveying
e The Registration Estate Office: in charge of the parcel
registration
e. The State Owned Land Office: in charge of managing the
State-owned land and responsible for the development of
land use scenarios for investors in real estate.
A possible solution is to use the existing government agencies
as nodes of a GSI system and the concepts of VE as outlined
above. By linking them, their workflows and data, the three
agencies behave as a ‘virtual’ Land Information Agencv.
The participating agencies require a service orientation attitude,
clear business process definitions, high commutment for col-
laboration and ICT infrastructure to create and maintain the LIS
which will support the land market players and other organiza-
tions as it participates in the National GDI (NGDI). A prototype
was developed at ITC, in the framework of the TMS/ESA Pro-
ject for capacity building in the Egyptian Survey Authority,
[14]. Figure 3 depicts the participating organizations and the
services thev provide in the ‘Virtual’ Land Agency. In addition
to the above mentioned organizations, is the Information. and
Communication Technology (ICT) supply information service
which interact with the main users of the LIS. The other com-
ponents which support services such as finance, user interface,
etc. are left out as they are of the scope of this paper.
The tool used for the agencies, or enterprises to interact with
each other, is the GDI broker or, as we prefer to call it, the GSI
