Abstract:An Enterprise Web GIS Solu

Abstract:
An Enterprise Web GIS Solution combines the knowledge of complex GIS systems with
the standards and best practices of Information Technology to design and implement an
end-to-end system that deliver geospatial data services, tools and applications on the
web. In order to design an optimal solution that fits well with an enterprise workflow and
provide robust, reliable, responsive and scalable map services and applications, it is
important to understand the various components of the web GIS framework and
consider the key factors that affect them when deciding on the type of technology stack
that works best.
This paper reviews the important factors involved in choosing the right framework for an
Enterprise Web GIS Solution and the various architectural components of a web GIS
system. It begins with an overview of the multi-tier dynamic Client-server system
architecture and implementation of specific configurations that web GIS systems apply
in performing geospatial data analysis. Next, it introduces the web GIS System
Architecture setup at Columbia University’s Center for International Earth Science
Information Network (CIESIN) as a case study. Using the knowledge gained from our
implementation experiences, it then evaluates and compares the system components
based on factors such as workflow, performance, backward compatibility, scalability,
interoperability and total cost of ownership (TCO). Finally, this paper concludes on the
note that these are the important factors to consider while designing an Enterprise Web
GIS Solution. However, it is also important to note that every enterprise has its unique
situation, business needs and strategic interests and the importance given to these
factors may vary accordingly.
Introduction:
GIS Desktop tools and applications have enabled users to view and analyze spatial
data in its proper format. With the evolution of GIS, the sophistication of these analytical
tools has increased tremendously, thereby increasing the cost and time required to
understand and use these tools efficiently. Additionally, most end-users today are
interested in the interpretation of the final results in its final format or through visual
representation.
Web GIS provides GIS users easy access to geographic information data, spatial
information and GIS modeling and processing tools. It provides an open and distributed
architecture for disseminating geospatial data and web processing tools on the internet.
This makes it easier for larger organizations to distribute maps and tools without time
and cost restrictions to the end user. To provide a successful Enterprise Web GIS
Solution, it is required to understand the complexity of the implementation as a process
rather than a step [Alesheikh, Helali & Behroz, 2002].
Understanding the complexity of GIS:
Geographic Information Service is a very complicated information service that requires
a different solution than other types of information services. The contents of geographic
information vary in different scales, resolutions, domains and times. Another complex
feature of geographic information is the ability to overlay different layers of spatial data
to generate new layers of information.
Development and Operational Issues:
From the development perspective, most current web GIS systems adopt a quick, adhoc
technology centered solution for open and distributed GIS that are neither
sustainable nor scalable. Once the technology changes, all ad-hoc solutions of the old
system are abandoned and are redone for the new system [Peng & Tsou, 2003].
Another problem is that current implementations focus more on data and less on
processing tools.
From the operational perspective, it is very difficult to separate the various web GIS
components into simple, modular and independent parts. Ideally, the interactions
between these components should be extensively defined with the clear definition of
their relationships [Peng & Tsou, 2003].
Web GIS architecture:
Basic components:
Client: Typically, the client or the user side of the web refers to the web browser on the
user’s machine. In the web GIS world it refers to a place where users interact with
spatial data and analysis tools. It is also a place where GIS programs display different
forms of output to the user based on commands, tools and tasks that are triggered by
some client-side and server-side actions and may have some business logic associated
with it.
Server: The web GIS server architecture generally has four components: web server,
application server, map server and data server.
Web Server: The web server responds to requests sent from the web browser via
HTTP. Any web site that is published on the Internet must have a web server program
running in the background: e.g., Apache, a web server that is supported on multiple
platforms such as UNIX, LINUX, and Windows. The web server can act as a proxy
strengthening the system security and balancing the load between application servers in
a cluster