Home Articles GIS data dissemination: A new approach through web technology

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.

GeoMedia Web Map was able to address these problems; the highlights are as below:

Data Exchange and Data Security
GeoMedia Web Map connects directly to the GIS data in its native format, whether it’s in Intergraph’s MGE format or Arc/Info, Arc/View etc. When the main GIS data at the HQ (central server) is published on the web, users at the taluka level (clients) or other places will be able access this data through Internet/Intranet. This avoids the traditional process of providing data through media thus ensuring a faster method. Since the data stored at the server fully under control of the administrator, the security of the data is maintained. Users cannot make any changes to the original data through Internet/Intranet, unless they get an authorisation from the administrator to do so. Also the administrator can control specific data to be accessed by specific user, i.e. if a particular user user has to view a particular data or a part of it, the administrator can control this. Thus access through Internet/Intranet ensures a fast and secured data access.

User-Friendliness and Easy Viewing & Querying
While publishing the data, considering the awareness in browser usage, the interfaces (web pages) are designed in such a way that it appears familiar to the user. Ths the user-friendliness is ensured while viewing the GIS data. Query Structures as per the GS project and the user’s requirement are pre-designed in such a way that the user has only to enter desired values or choose some values from a pop-up menu/list/combo-box and get the result to this query. This way the GIS viewing and querying does not need any expertise in GIS.

Data Updation
Given the authority by the DATA administrator at the central server, a user can modify the database (inputting a new record or modifying an incorrect information etc.) whenever required, through the web. This change in the database will appear instantly so that other users accessing the same data will view the modified data. Thus updating of GIS data and transforming the updated data to the users through media (CD or Tapes etc.) are avoided and at the same time this also ensures a quick, secured and easy updation of the database.

Low Cost
While accessing the GIS data from the central server through Internet/Intranet, the client needs only a web browser (Internet Explorer or Netscape Navigator). There is no need of installing sophisticated GIS software (which has been used to create the GIS project) at the user’s site. The GeoMedia Web Map software installed at the centralserver used to publish the GIS datatakes any GIS data created using any major software packages such as Intergraph’s MGE, ESRI’s Arc/Info or Arc-View etc. So once GeoMedia Web Map connects the GIS data directly from its native format, the data will be published and finally the users (clients) will be able to view and query this data through a browser only. Thus the “Thin Client” concept is fulfilled and the whole process becomes free with the operating system) at the client site.

Work Flow:
In order to utilise the above concept using the web technology and GeoMedia Web Map, a GIS project created by Space Application Centre, Ahemdabad was used. The project, which was created using Arc/Info software, had to be published on the web without any recreation or translation.

For this web-publishing project, Intergraph’s GeoMedia Web Map software was used on an Intel Pentium Platform with Windows NT 4.0 server operating system, to access the Arc/Info Project directly and publish the GIS without recreating the project or translating it.

The desired interfaces (web pages) were designed with menu bars, query frame, report frame and graphic frame. The Features to be published from the original GIS project were selected and accordingly the display settings for each feature were defined. This defines the way a particular vector maps on the web GeoMedia web Map enables the display of active (intelligent) vector maps on the web, ensuring that when the user can also get the graphic map by clicking on the attributes from the database will appear. The user can also get the graphic map by clicking on the attribute record. While publishing, the structure of reports (i.e. the details from the database to appear) is also designed. This is quite important as sometimes in the database certain information are written in a symbolic or in short form, which while displaying may not be very clear to the user. This can be controlled while designing so that exactly what should appear on the screen corresponding to that column of the database can be defined. This becomes quite simple for the user. This way some critical information can also be avoided from being displayed. Apart from the display parameters and report structures, the query, a complex query (query between multiple columns), join query (query in the join table) etc. are defined. This query structure specifies the user just to enter a value or choose a value from the combo box. The rest query syntax is pre-designed so that after the user enters or choose a value, the query is performed and the result appears. Corresponding to the query, the vector map is also displayed directly from the database.

Thus finally this GIS data can be accessed through web with a completely different look and can query on the database from a client machine having a net browser (Internet Explorer/Netscape Navigator)

Conclusion
This benchmark proved the capabilities of web technology and Intergraph’s Geomedia Web Map for publishing the GIS Data on web. With the use of this new technology, the major hurdle, causing in the way of availability of GIS data for the large section of Viewers is obviated. With the advent of OPEN GIS, the GIS data exchange across platform has now become a reality. GeoMedia Web map will make GIS data accessible at all levels, particularly for users and viewers, which will accelerate the development planning activities.

Particularly in India, where large scale projects such as NRIS Project, gets implemented through out the country, this technology is definitely going to prove as the key for making GIS acceptable and accessible at all levels.