Dissemination and Sharing of Geo-spatial Information Derived from IRS Data on Land use and Land cover of India

Home> Web Development

Go Back

Web GIS

The network base GIS applications like web based GIS, Enterprise GIS, distributed GIS etc., provide almost all functionalities and capabilities of traditional GIS software to the users for querying and analyzing the geo-spatial data without having any specific GIS software at their end. In addition, it has additional functions that take advantages of the computer network/Internet and its associated protocols. With network base GIS service, users can access data layers directly from a database server with the option of utilizing the data dynamically or downloading areas of interest and working locally. Effective deployment of network base GIS requires data standardization and sharing, these include appropriate GIS software, operating system software, database software, powerful servers, and high-performance reliable RAID storage.

Internet GIS is an integrated client/server network system where web browser application provides Internet users to access GIS applications software residing at server end and client on web can work with GIS data interactively on the Web browser. The Web GIS applications can categorize into two major categories i.e. server-side applications and client-side applications. Server-side applications rely on GIS server (usually reside on a remote server) to perform all GIS operations, while client-side applications perform GIS operations and processing in the Web browser on the user’s local machine.

Advancements:

Development of AJAX (Asynchronous JavaScript and XML) and image tiling techniques are the recent advancements in Web-based GIS applications/visualization. Traditional Internet GIS applications and Web-based mapping tools always suffer from the slow response and the lack of high resolution images because of the limitation of image data sizes and the client/server communications. These two new technologies ( AJAX and image tiling) can improve the performance and repose times of Internet GIS application significantly.

AJAX is not a single technique but a combination of multiple web techniques for creating fast response, interactive web applications.AJAX can send user's requests to the web server to retrieve only the data needed by the request. Therefore, the total amount of images or data interchanged between the client browser and web server will be reduced significantly. For example, if users need to zoom-in to a new map area in a Web map browser, the server will not need to reprocess the whole Map page content but only to re-send the smaller area of map requested by the user. By using Simple Object Access Protocol (SOAP), JavaScript, or similar XML-based web service protocols, AJAX applications users can have very responsive actions.
The introduction of tiled images is to improve the application performance by allowing the application to process an image region within a number of tiles without bringing the entire image into computer memory. In Image tiling, the large size image is first shrunk down to different resolutions for building multi-level image pyramid layers, and then each layer is further broken into smaller tiles in a separate file with a standard naming convention related to the specific tile position. To represent the reality, users typically see only part of the image on the fly instead of the whole one. The adoption of tiling technique is to aid the presentation of very high-resolution imagery and halts the unnecessary work on off-screen sections. This prevents the memory overload, decreases processing and bandwidth requirements, and making it possible to move quickly from one section of the image to another. By combining both the AJAX and image tiling technologies, the Internet GIS application developed have much faster performance and interactivity comparing to the traditional Internet mapping or Web-based GIS tools.

Tools and Technology used:

With the goal of enhanced geospatial data sharing within and across organizational boundaries, organizations increasingly focus on enterprise, or institutional, solutions to effective information exchange, thereby avoiding redundant systems and services and incompatible infrastructure. In recent years, including smaller communities and organizations have also started realizing the benefits of implementing enterprise GIS from independent, stand-alone GIS systems to more integrated approaches that share resources and applications.

Effective deployment of Bhoosampada requires a multi server configuration where the data server, application server, map server and web server is required as an individual identity and are installed and configured in network architecture.  Bhoosampada is having two map viewers viz 1:1 Million and 1:250K for general and registered users respectively. The mapviewer for general users have been developed using open source Geospatial tools with limited functionalities whereas to enable registered users with more GIS functionality, another mapviewer has been developed using COTS package. The system architecture of Bhoosamapada incorporates the following technology: Database server (Postgre SQL, Oracle 10G), Spatial Database Engine (Arc SDE, POST GIS), Web server (Apache, MS IIS), Internet Map Server (UMN Mapserver, Arc IMS), and the programming environments (ASP and PHP). 

Database Server: 

A multi-user GIS requires a database and GIS tools to work with the spatial data. Many types and sizes of spatial databases can be built, but typically, as project requirements evolves, spatial database will grow in size and number of users. In addition to unlimited data storage capability, database server also provides an excellent facility of improving performance of data access in distributed environment. The multi tier architecture also provides an excellent data security management utility. Spatial Database Engine plays a fundamental role in a multi-user GIS. This works as an application server, delivering spatial data to many kinds of applications and serving spatial data across the Internet. This also provides the gateway between the GIS and the RDBMS to share and manage spatial data as tables. In a heterogeneous database environment, where a number of different departmental or personal database systems are used, it provides a common model for geographic information. This allows taking full advantage of the facilities of RDBMS has to offer for integrating GIS information with the rest of organization's or project specific data.

Map Server:

Map server is a software package or program, which is responsible for web map rendering the GIS data and designed to serve maps across the Internet. Sometimes these maps are just static images allowing simple panning and zooming, whilst others are more complex pages, which allow fuller interaction between users and maps.

Web Server:

A Web server is a computer program, which uses the client/server model and the World Wide Web's Hypertext Transfer Protocol (HTTP), serves the files that form Web pages to Web users. 

AJAX is Implemented in KaMap: Image tiling concept using PHP and Java Script : Open source programming environment for web application development;

Major Functionalities:

The user friendly GUI has been customised to enhance the outreach of available data and information. It facilitates the user to have GIS functionalities to meet specific requirements through simple web browser with out any specific software at client end. The centralised database server located at NRSC enables Easy data updation, Concurrent access of same data by several users, Easy and fast data dissemination to authorized users through Common platform for data access and sharing.

• Interactive browsing of LULC map up to original scale (1:250K) using scale rendering;

• Basic GIS functionalities like zoom in, zoom out, panning, identify, zoom to full extent etc;

• Query on LULC statistics and census information at state and district level;

• Dynamic graph creation for query outputs;

• On-the-fly GIS analysis like crop area statistics, per capita analysis, change analysis etc.;

• Various layer overlays on LULC map and satellite imagery;

• Data request for download and saving information at client end etc.

For further details, Feel free to contact the developers of this portal:

This site is best viewed in Internet Explorer 5.0 and above. Please do not use pop-up blocker to access this web site..