GIS data dissemination: A new approach through web technology
Subhasree Nayak
Rolta India Ltd.
Gone are the days when data dissemination and information exchange across the world used to involve a troublesome and lengthy method. Undeniably, the biggest advance in information dissemination has been the World Wide Web. The Internet, now has opened all the channels for data exchange making it possible in just a matter of seconds. The web technology has brought revolutionary changes in communicating information, Geographic Information System (GIS) being no more an exception to this. Through the web, now users can access a GIS, view a smart intelligent active Vector map, perform relevant queries without even having a GIS software installed in the client's machine. Now GIS data is being published on the web all over the world and GIS on Internet is no more just a concept.
GIS: Current Scenario
With the growing need of GIS in all applications, the main problem has been the availability of data, use of a sophisticated GIS tool and need of GIS expertise. GIS data and its use, until recently, have only been accessible to a small percentage of the participants in an organisation, the "GIS Expert" group. The whole GIS community can be visualised as a three-tier configuration consisting of the "GIS Expert Group", the "GIS Desktop User Group" and the "GIS Viewer group". The GIS Experts representing 1-2% of the total no of GIS users, spend 80-90% of their time for creating and maintaining the gIS data. The "GIS Desktop Users Group", number 10 times more users than the Experts and conduct decision support activities spending 10-20% of their time with the geographic data. This group's number is growing rapidly and their ability and expertise to utilise GIS data is growing every day. The third group of the GIS community, the "GIS Viewers" is the largest in number with an incredible appetite for immediate data. This group wants to assemble data as quickly as possible for unlimited reasons, without bothering about "Who created the data" or "How the data is created" etc. Also these users are not GIS Experts, hence would like to have an easy access of the data which will not require any expertise. But this group is responsible for popularising GIS. For these demands, what is needed is availabilityof GIS data for accessing from a common platform and easy to use tool for use (querying) of this data without expertise in GIS.
GIS and Web Technology
With the advent of Web Technology, the urgent need to access intelligent, GIS data over the media has been appreciated. This in fact has highlighted the problems/hurdles causing in the way for such data. This web technology can be used across the world through Internet or among the various departments through Intranet. With the rapid growth of Web Technology because of the low hardware cost and decreasing requirement of software at the client level, specific new technology for GIS data viewing is coming up as the key for deploying geographic data to the user community. Using these technologies, intelligent, smart, vector-based map can be published in an open Active-CGM format. This permits the publication of both vector and raster data. The amount of vector data sent over web could be three to four times less than the amount of raster data needed for equivalent resolution thus resulting in faster response time and greater productivity. This "Dynamic Map Creation" ensures fewer data downloads and more efficient use of server resources. To do all these, the user at the client site does not need any GIS software to be installed in the computer, nor any expertise is required to view the GIS over web. The user can browse through the GIS data using any popular Internet browser available in the market today, such as Internet Explorer or Netscape. This whole technology make a simplified GIS access with almost no cost at client site, thus a cheaper solution.
A Typical Configuration
Case Study
In India, this technology has been proposed for the vital NRIS project, where the GIS data dissemination through Internet/Intranet, is a key requirement. For this Intergraph's Geomedia Web Map has been proposed. As a part of the proposal, a benchmark project was undertaken. Certain highlights of the same are provided below.
Objective:
The objective of this project for publishing the GIS project on WEB is based on the concept of NRIS project implementation, which is visualised as a network of GIS nodes covering the districts and states and the entire country. These nodes will be the repositories of resource information in the spatial domain and will provide vital inputs to decision-making at districts/states/centre levels.
Hence the aim for publishing the GIS data on WEB is to make the GIS data created and stored at the Head Quarter Level available to the users at lowest administrative level. The user at this level may not be (which is usually true) a GIS expert but would still like to use the GIS data. By giving the access to the GIS data to such users, the GIS data administrator at the HQ level has to make sure of the security also. Giving only the relevant data to the particular user for local use, while storing the original data at the HQ, will involve a cumbersome operation of spending the data through media (CD or Tape), installing a GIS software (which is being used to create the GIS) at the user's site, training the user in the software, maintaining the software at the client site etc. Ultimately this ends up with a tedious and lengthy procedure with a huge amount of money spent.