Traditionally, the Geographical Information
System (GIS) mainly worked on the desktop computer, to create, manage, analyze
and display geographical information, which is also popularly known as Desktop
GIS. It has monolithic structures where all the three
necessary elements of the software: presentation, logic/application and data
are tightly coupled and present in a desktop computer that are not
possible to separate into individual module and store in different computers.
Architecture of this system is closed, centralized and single-user oriented.
Certain limitations of desktop GIS software
are:
- Complicated user interface requires training so it usually disallows an immediate and fast solving of simple GIS tasks.
- Every user has to buy full license copy software, even if only a small part of available functions will be used. Although these users utilize only few functions of this software but have to pay for the full software, not for only those functions they require.
- Generally, Desktop GIS software are specific task oriented. So as a GIS user, one should have proper working knowledge in several GIS software which sometime become very difficult to acquire.
- It is accessible only from the computer on which it is installed.
- Major Desktop GIS software still follow a proprietary technology that uses proprietary data formats. Therefore, interoperability within data formats are missing.
To overcome the above-mentioned
limitations, an important breakthrough in GIS technology was the deployment of
GIS data and functionality in the Internet or more specifically on the Web and
is popularly known as WebGIS. Major benefits of WebGIS technology are to
allow any remote users at any time, using variety of client devices, to access
distributed geographic data and processing tools present in different computers
(servers). The client devices could be desktop computers, laptops, pocket PCs, Personal
Digital Assistants (PDAs), mobile phones or hand-held Global Positioning
System (GPS) receivers and all these devices should have internet
connection. The GIS servers could be distributed at different locations.
Common examples of WebGIS
applications (also called Geoportal) are Google Maps, Bing Maps or Yahoo! Maps
that present interactive webmaps of the entire world to the user. These websites
are also providing easy-to-use map navigation tools (zooming/panning etc.), map
analysis facility and many more as a service to their users. For accessing
these websites, user do not need to use any GIS software or formal training on
GIS; what they require, are internet connection and any web browser program
such as Internet Explorer, Mozila, Opera etc.
The use of the Web as a dissemination
medium for GIS data, maps and functionalities (processing tools) can be
regarded as a major advancement in GIS and opens many new opportunities, such
as cheaper dissemination, more frequent and cheaper updates of data and
software, personalized map content, distributed data sources, sharing of
geographic information and GIS web services.
Desktop GIS can only serve the dedicated
users with sophisticated software and hardware resulting in less or no impact
to the public. Web technology as a digital communication medium enhance the
capability of GIS data and software application by making them more accessible
and reachable to wider range of users, planners and decision makers. WebGIS is
a mechanism to deliver GIS data, maps and GIS services on the internet using a
cheap and easy way. WebGIS users are able to access GIS applications by only
using a web browser program, without purchasing any GIS software. In short,
basic functions of GIS remain, but it gets online and everybody can use or
access it. At this point, we should introduce another term ‘Web mapping’
that is closely related to WebGIS.
The Web mapping is the process of
designing, implementing, generating and delivering maps on the Web and its
product. WebGIS is similar to web mapping but with an emphasis on analysis,
processing of project specific geographic data and exploratory aspects. Often the terms WebGIS and Web mapping are used synonymously, even
if they don't mean exactly the same. In fact, the border between the web
mapping and the WebGIS is blurry. Webmaps are often a presentation media in
WebGIS and are increasingly gaining analytical capabilities.
