Maps on the web provide a new paradigm
for how people everywhere access and use geographic information. We use GIS
maps on our desktops , the web , tablets , and smartphones for a sophisticated
range of activities to apply advanced geographic information . web GIS is a
transformation of GIS that brings analytics to spatial data in away that wasn’t
possible before .
Previously satial data had to be
processed , modified , and extracted to answer a predetermined set of questions
. now the is transformed into web maps or services that are mashed up with
different layers into a web gis , which provides the flexibility to answer any
possible question . the data is ready and waiting to dynamically answer
questions . it no longer needs to be processed for each individual question .
web GIS is a much more flexible and agile workflow . web GIS brings GIS into
the hands of the people . it reduces the need to create custom applications ,
provides a platform for integrating GIS with other business systems , and
enables cross-organizational collaboration . Web GIS allows organizations to
properly manage all their geographic knowledge . At the heart of Web GIS is a
mapcentric content management system .
Web GIS is a type of distributed
information system , comprising at least a server and a client , where the
server is a GIS server and the client is a web browser , desktop application ,
or mobile application . in its simplest form , web GIS can be define as any GIS
that uses web technology to communicate between a server and a client .
Here are a few key clements
essential to web GIS :
·
The server has a URL so that clients can find it
on the web .
·
The client relies on HTTP specifications to send
requests to server.
·
The server performs the requested GIS operations
and sends responses to the client via HTTP.
The format of the response sent to the client
can be in many formats , such as HTML , binary image , XML (extensible markup
language ), or JSON (java script objects notation ).
AN ARCHITECTURE OF AN OVERALL WEBGIS SYSTEM
To identify subsystems of an overall
WebGIS we started from a general assumption that
geoinformation related to some area
(i.e. city) cannot be captured, stored and maintained in a single
organizational unit GIS. Some of this
information can have mutual and public importance, so it
should be shared and be accessible
over Web.
Suggested architecture relies on a
client/server model. A subsystem that acts as a client that enables
access to geoinformation is a WebGIS
portal, while the function of sharing (role of a server) is
realized by expanding traditional GISs
with a WMS and a WFS Web interfaces (Web-enabled GIS).
Using of OGC WMS and WFS interfaces
for building WebGIS systems can be also found in
(Korduan
and Bill, 2004). Figure 1 illustrates interrelation between components that
correspond to subsystems.
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