GIS data dissemination: A new approach through web technology
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.