Introduction:

GIS is an emerging multidisciplinary technology involving disciplines namely geography, photogrammetry, cartography, remote sensing, surveying, GPS technology, statistics and other disciplines concerned with handling and analyzing spatially referenced data. The technology is growing at very fast speed and has taken a quantum jump from the era of mainframe computer to workstation and to desktop-based PC systems. With the recent advances in broadband and wireless communication technologies as well as the dramatic increase in internet technology it is promising to extend further the reach and range of GIS user working in offices and laboratories in the field or at home would lead to the development of internet GIS or web enabled GIS. Traditional GIS can only serve dedicated users with sophisticated software and hardware resulting in limited impact to the public. The Internet technology as a digital communication medium enhance the capability of GIS data and software application by making them more accessible and reachable to wider range of users, planners and decision makers. The web enabled GIS would facilitate decision making at the strategic, tactical, and operational levels; support for performance of administrative operations; and serve as a gateway for decision-makers and general users to access the system conveniently and effectively.

The aim of this article is to familiarize the reader with the Internet GIS technology and web environment in which it has grown, the technical issues in the future growth and finding its scope in wider application areas.

Related development:

The Web Environment The internet is a vast communications network that today links together more than 4 million computers all over the world. Krol 5 coined the term “Internet”, to a global network of computers connected through communication devices to one another for information sharing 1. The rapid growth in Internet activity over the last few years has produced a literal explosion of information and revolutionized the way it is disseminated. The most important capability of the Internet is to integrate information from various sources in a seamless fashion 3. The web environment enables users all over the world to share their data and practice cooperation on scales that was earlier impossible. The Internet connectivity is increasing at a very fast rate and it will become unique source of many application areas such as internet web publishing, voice email/electronic mail, online interactive training, telnet applications, online library information, online shopping/advertising and internet GIS.

All computers on the Internet communicate with one another using the Transmission Control Protocol/Internet Protocol suite, abbreviated to TCP/IP. Computers on the Internet use client/server architecture. Since late 1993 Internet, based WWW has emerged as an alternative means of accessing, viewing, and distributing spatial information in combination with web browsing software packages like Netscape and Microsoft Internet Explorer. The World Wide Web (WWW) is a system of Internet servers, which was developed in 1989 by Tim Berners-Lee of the European Particle Physics Lab (CERN) in Switzerland 7. It supports hypertext to access several Internet protocols on a single interface Almost every protocol type available on the Internet is accessible on the Web. This includes e-mail (Simple Mail Transport Protocol or SMTP), Telnet (Facilitates login to a computer host to execute commands), and Usenet (Network News Transfer Protocol or NNTP (Distributes Usenet news articles derived from topical discussions on newsgroups) News. FTP (File Transfer Protocol) is another important protocol in web environment. This network protocol is both a program and the method used to transfer files between computers. Anonymous FTP is an option that allows users to transfer files from thousands of host computers on the Internet to their personal computer account. In addition to these, the World Wide Web has its own protocol: Hypertext Transfer Protocol, or HTTP. The Internet uses the Hypertext Transfer protocol (HTTP) to communicate queries and response across the Internet. HTTP is the client-server protocol; it takes request from client and transmits the request to web server, which then sends back its response.

Internet GIS:

The integration of GIS and Internet technologies is allowing GIS professionals to solve one of the most important problems inhibiting information utility: How to provide access to information and data without burdening end users with complicated and expensive software. Internet is a perfect means of GIS data accessing, analyzing and transmission. The World Wide Web, FTP (file transfer protocol) and HTTP programs make it convenient to access and transfer data files across the Internet. The Internet provides GIS users easy access to acquire GIS data from diverse data source in distributed environment. GIS users can use and download the data by sending the request through web browser application.

The World Wide Web is fast becoming a standard platform for Geographic Information System (GIS). It is a means for GIS users to exchange GIS data, conduct GIS analysis and present GIS output in the form of maps. Internet has facilitated three major changes in GIS 9: (1) Access to data; (2) Transmission of data; and (3) GIS Data analysis. Therefore, Internet GIS is a special GIS tool that uses Internet as a means to access and transmit remote data, conduct GIS analysis and make spatial output. The Internet GIS is often called Web GIS, Online GIS etc. The Internet GIS has several potential advantages over standalone system include-1) Worldwide access; 2) Standard interface and 3) Cost-effective maintenance 9.

The Internet GIS applications provide all or almost all functionalities of traditional GIS software. In addition, it has additional functions that take advantage of the Internet and its associated protocols. The user of Internet GIS application can use traditional GIS tools for analyzing their data without having any specific GIS software. 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. The client on web can work with GIS data interactively on the Web browser without owning GIS software on his/her local machine. Internet communications software such as Microsoft NetMeeting facilitates users to emulate a map server by sharing Windows-based GIS applications with others over the Internet 6.

A client/server application has three components: a client, a server, and a network4 .The client sends a request to the server, which processes the request and returns the result to the client, the client then manipulates the data and/or results and presents to the user. Internet GIS applies the client/server concept in performing GIS analysis tasks.

The Internet GIS is a distributed system and can access distributed database in order to perform distributed processing 4. Internet GIS use this capability of Internet for data sharing, analysis and querying. The technology is dynamic, for example, once any client (s) or database administrator updates the data or information at server end, it will available for all the clients on web at the same time. The Internet GIS can also link with real time information, such as satellite images, traffic movements and accident information by real time connection with the relevant information sources. The applications developed are cross-platform and accessible through any web browser.

The Internet 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 analysis, while client-side applications perform GIS analysis and processing in the Web browser on the user’s local machine.

Server side Internet GIS:

In a server-side Internet GIS application, a Web browser is use to generate server requests and display the results. An Internet GIS server usually combines a standard Web server, a GIS application server and the GIS databases server. In server side Internet GIS application, all functionality resides completely on the server(s). The user (s) sends the request from web browser, web browser transferred the request to a web server and web server passes the request to a GIS application server. GIS application server runs an address-matching routine, generates a map graphic, converts the graphic to Web format, wraps the image in HTML and sends it back to the Web server, which then returns the response to the client as a standard Web page. In server-side Internet GIS, all the software, as well as the GIS databases, resides at a server end 9. Server-side applications require proprietary software, but the software stays on the server. Data transmitted to a Web client are in standard HTML formats that can viewed in any Web browser. The server end architecture of server side Internet GIS application can have single computer, dual computer or multi-computer. The concept of single computer, dual computer or multi-computer is explained in coming paragraph.


Advantages of Server Side Internet GIS

• Application Development and maintenance is easy.
• Application can be assesses through any Standard Web browser.
• Issue of platform dependent development is no more a problem.
• All most or all the important functionalities of GIS can be performed at served end.
• Handling of large databases is easy with latest developments.
• Low bandwidth is sufficient.
• Centralizes administration of data and GIS application software.

• No viable vector formats.
• GIS operations are quite difficult.
• Low graphics quality.
• Primitive GUI.
• Performance is slow in GIS operation.
• Information re-transferred for each request.

In a server side, Internet GIS, performance of the application is major issue. In each client request, it extracts the information from server, which reduces the performance of the application. When users reset a display window by panning or zooming, turn a layer on or off, or take any other action, the request must be sent to the server and returned. This results in many requests, which can cause poor performance.
Example (www.biospec.org)


Client Side Internet GIS:

In client-side Internet GIS, the client support GIS operations. Some systems move a substantial amount of GIS functionality to the client, and some only enhance the user interface slightly. Client-side solutions typically implemented by augmenting the Web browser with Java, ActiveX or plug-ins. Some client-side solutions require users to install a complete client application. However, to implement client-side solutions of any kind, software must be transferred to users. In a client side Internet application, a part of application or full application is installed in client’s machine. The primary advantages of client-side solutions are the abilities to enhance user interfaces, improve performance and implement solutions.

Advantages of Client Side Internet GIS

• A document/graphics standard is not required.
• Image quality is not restricted to particular format.
• Not restricted to single-click operations.
• Excellent performance for operations that occur locally.
• Less Internet traffic required.
• More users friendly.

Disadvantages of Client Side Internet GIS

• Requires users to obtain additional software.
• Platform / browser incompatibility.
• Initial download times can be substantial if databases transferred.
• Users must wait for software to download.
• Overall performance can be low with large databases.

Building units of internet GIS:

So far, the reader must have a fair idea on the tools essential for setting up an internet GIS architecture. In view of launch of large number of internet map servers in the market, it would very early to name few of them. However, in table 1, a compilation on possible choices on products\vendors has been enlisted.

Table 1: Required Components of Internet GIS

Components	Type	Provider/vendors	Status
SERVER END
Operating System	Software	Microsoft, LINUX etc.	Commercial
Map server	Software	ESRI, Rolta, Microsoft etc.	Commercial
Web server	Software	Microsoft-IIS, Apache Web server	Free
Data server	Software	Oracle, IBM-DB2, MYSQL, SQL- Server etc.	Commercial
Spatial database management system (Optional)	Software	Oracle, ESRI-ArcSDE	Commercial
Server *	Hardware	SUN, HP, Compaq, WIPRO, IBM etc.	Commercial
Internet connection	Networking	BSNL, VSNL etc	Commercial
Domain name	Networking	Net4India, Yahoo etc.	Commercial
CLIENT END
Web Browser	Software	Microsoft, Netscape etc.	Free

The server configuration can be taken as single server, two servers or multi server architecture. In the Internet GIS architecture, we need web server, data server and map server as separate identity. In the single server configuration, the Web server, application server, and database server are installed on a single computer. In a two-server configuration, the Web server is installed on one machine, and the application server and database server are installed on a separate machine. In the multiple server configurations, each component is installed on a separate computer. The ideal configuration for a particular deployment depends on the anticipated number of users visiting the site each day, and number of maps services. ESRI makes the following recommendations based on the number of anticipated daily users.

Configuration	Anticipated Number of Users
Single server	100 - 1000
Two server	1,000 – 1,500
Multiple server	1,500 +

For client side Internet GIS application development we need additional components at client end –:

• GIS software
JAVA plug in for JAVA base application.

The component- map server is most important for launching a Internet GIS application on web. Most of commercial map server support RDBMS. There are many Internet map server products available in the marked, supporting for publishing the maps on Internet and set of tools for interaction and response. An overview of few commercial or non-commercially available products is given below- :

Table 2: An account of available map servers and their vendors

Product	Description	Web address
ArcIMS	This is a most popular map server developed by ESRI. This product has been launched with ArcSDE having geodatabase concept.	www.esri.com
GeoMedia WebMap	GeoMedia WebMap, Intergraph’s Web-based map visualization and analysis tool, provides real-time links to geospatial data warehouses	http://imgs.intergraph.com/gmwm/default.asp
AspMap	AspMap is a Web mapping component for embedding spatial data access, display and analysis capabilities in Web applications and services. AspMap supports ASP and ASP.NET	http://www.vdstech.com
Demis Map Server	The Demis Map Server provides interactive access to the Demis Map Engine over the Internet using protocols defined by the OpenGIS Consortium.	http://www.demis.nl
GEO-DATA	Use GEO-DATA Explorer (GEODE) to access, view, and download information from geo-spatial databases containing a broad spectrum of data produced by the USGS and other government agencies.	http://geode.usgs.gov/
GeoServ	GeoServ delivers interactive maps over the Internet. Developed by the Terrain Sciences Division of the Geological Survey of Canada	http://www.geoserv.org/
MapGuide	MapGuide is AutoDesk's (the makers of AutoCAD) map server. Access links to demo and customer online applications	http://usa.autodesk.com
Map-TV	Map-TV is a map server that has a built in web server. This map server uses ESRI shape file format for data display.	http://www.spatialmedia.com/
WebView	WebView is an ArcView-Extension that provides you with the possibility to present your Views on the Web or on CD ROM	http://www.zebris.com/english/main_produkte.htm

Source - http://gislounge.com/ll/webgis.shtml


Table 3: A lists of free map servers available in market

Products	Description	Web address
ALOV Map	Free, portable Java application for publication GIS data to Internet and interactive view on web browsers. Site contains live demos	http://alov.org/index.html
GeoTools	GeoTools is a free Java based mapping toolkit that allows Maps to be viewed interactively on web browsers	http://www.ccg.leeds.ac.uk
iMapper	Free user-friendly ArcView extension. The purpose of this extension is to allow ArcView users to display their maps and data to people over the Web in a quick and easy fashion without having to have a map server	http://www.imapper.com/
Jshape	Free JAVA-based webserver using ArcView shapefiles for data delivery.	http://www.jshape.com
MapIt!	MapIt! is a web-application that lets you navigate raster-maps through your web-browser and lets you zoom in and out and select objects and object classes that are identified on the map.	http://www.mapit.de
MapServer	MapServer is a CGI-based application for delivering dynamic GIS and image processing content via the WWW.	http://mapserver.gis.umn.edu

Source- http://gislounge.com/ll/webgis.shtml

Application areas:

The Internet GIS application can be utilized in many real time applications areas like-

• Biological resource conservation and management

Conservation of biological wealth using modern means of information techniques has strongly emphasized under the Rio agenda, 1992. Sharing the information collected on positional aspects of broad variety of habitats and phenomenon across the globe has substantial importance for conservationists, policy makers, government and local communities for taking priory decisions about the resources they use. Large databases collected through various research and surveying organization at national and international level could be shared for real time implementation. The location map on occurrence of faunal and floral species, the forest types, wetlands, coral reefs, biogeogrphic regions, climatic regions and protected areas and other such related attributes can have immense value if they will be well shared and put to updating.

• Disaster management and mitigation

Maps and spatial information are important components of the overall information in case of any disaster event (flood, earthquake, cyclone, landslide, wildfire, famine, and so forth). Hence mapping and spatial information acquisition becomes vital for any disaster management effort. In a vast, and disaster-prone country like India, considering the vulnerability of the country to disasters of various types, Internet GIS can be very much used for coordinating and managing the spatial data display and analysis needs of the various agencies involved in the various stages of the disaster management cycle, for any natural peril, and for any region.

• Spatial data infrastructure

National Spatial Data Infrastructure (NSDI) for India is an initiative undertaken jointly by Department of Science and Technology and Department of Space, Govt. of India. NSDI for India is aimed at encouraging collection, aggregation and distribution of spatial data on different themes on a common defined set of standards and formats by different mapping agencies in India. This infrastructure of data will provide metadata of all the data available with various participating agencies and facilitate users to obtain data as per requirements with a simple and smooth procedure from a common platform 10.

• Facility and utility management

Facility Information System (FIS) provide solutions to decision makers across the organization with immediate answers to complex business questions. By pulling together a huge amount of network status, outside plant, customer location, demographic and other location-related information in an easily shared and interpreted format, an organization can put mission-critical business intelligence at the fingertips of those who need it. Health services, location based services, real time application in vehicle movements,

• Business Process Outsourcing (BPO)

BPO [Business Process Outsourcing] has been the latest development in India today. The call centers provide the online business solution to its clients through Internet. The use of web GIS application in this field will be definitely beneficial for better service. The use of GIS in location base service, mobile mapping and other related development certainly benefited all corner of life.

Technical constraint and future prospect:

Internet GIS has arrived yet is constantly evolving technology. The fully interoperable Internet GIS becomes more promising as Internet standards and technologies rapidly grow. Currently, there are two major Internet GIS applications: server-side applications and client-side applications. Server-side applications have the client relying on a remote GIS server already discussed for their merits in the forgoing text. The initial development of linking GIS with Internet is by linking the GIS programs with the Internet server through a Common Gateway Interface (CGI). The spatial data server runs in the background at the map server and is linked with the Web server. The CGI script handles the information exchange between the Web server and the map server. This approach is mainly for simple map display and does not facilitate any direct interactions between the Internet user and GIS analysis.

The advent of Java-a portable, object oriented Internet language promises to remove many of the constraints inherent in early www protocols and further extends the capabilities of web-based data browsing systems. By moving much of the requisite display, processing, and analysis functionality to the client end of the Internet connection, performing delays due to server load and Internet bandwidth limitations may be greatly reduced. With a number of vendors and standards organizations (e. g. the open GIS consortium) now including it as an important components of an overall network based GIS architecture, Java based technology may eventually be one of the keys to developing more open systems of distributed processing of geographical data.

The new concept of Geodatabase is a pioneer effort towards fully interoperable Internet GIS. In the geodatabase concept, the spatial data is organized and stored in relational database management system (RDBMS), where the available non-spatial data in RDBMS can be linked easily with spatial data and the capability of database management system can be fully utilized for GIS data. Oracle spatial is another example of storing and managing GIS data in RDBMS, which gives more utility of Oracle database management system for GIS environment. The spatial or non-spatial data stored in any database management system always give better performance and secure data access in web applications. Like most software projects, there is more than one solution, but the best solution depends on the availability of resources and the requirements. Similarly, for development of any Internet GIS application, the best solution depends on the application requirements. By carefully analyzing requirements and planning an Internet GIS application, host organization can greatly simplify the development process. An understanding of the application requirements will allow the developer to make the right architectural choice for the application. The choice of right architecture is a critical factor that influences a GIS application's performance. In a web environment, performance is usually the most important factor, thus a developer should keep in mind the network performance when designing the database. The database normalization and indexing will provide the best performance for an Internet GIS application. Threading and Session Management are also two very important considerations that affect performance and scalability (http://www.giscafe.com).

In the present scenario, Internet GIS technology is not fully successful technique for GIS data analysis and decision-making in web environment. The raster operation in Internet domain is yet too be in evolving stage due to low bandwidth and large size of GIS data sets. The present available bandwidth is not sufficient for successful operation of GIS application in Internet domain. The sharing of spatial data into a sharable framework is also a major issue due to some map policies and restriction in geospatial data.

Since, Internet, a global network of computers connected through communication devices to one another for information sharing is not consider secure for sharing of restricted data. Although due to different powerful network security tools it’s not easy to harm any secure Internet GIS application, but some people have not faith in this technology yet too. The strong knowledge of network protocols and security constraints on Internet, definitely increase the success of web GIS applications.

Law and Policy Regime:

The law and policies on proliferation, maintenance and regulation of internet GIS services and application are at initial stages of conceptualization. The National Geospatial Data Clearinghouse (NGDC) is an example of Internet data access. It is a distributed archive of information -- distributed among potentially multiple nodes within an organization, but accessible to all users through a single point-of-entry, managed by the Federal Geographic Data Committee (FGDC). It is an open federation of spatial data servers using the same vocabulary and supporting the same search protocol -- Z39.50 protocol 8. The FGDC is assisting develop Clearinghouse nodes in the state, county and other non-federal sectors to form part of the NGDC in order to make the NGDC a more efficient data source. In Indian context, National spatial data infrastructure (NSDI) has already invited lots of discussion through the workshops and seminars at national forum. The Survey of India has the biggest archive of topological data; Department. of space (DOS) has a long array of satellite constellation in the orbits providing satellite imageries for monitoring natural resources, the other surveying organization of collect information on different aspects of biological diversity and land forms like BSI, ZSI, and GSI may initiate internet GIS in dissemination of information.

Cost estimate:

The Internet GIS based applications can be developed in the equal cost incurred for the devotement of simple web portal. The additional requirement is map server and high-end server (for better performance). The overall cost for development of Internet GIS application the best solution depends on the application requirements and selection of Internet GIS architecture.

Sources of information:

The issue of GIS data access and transmission on the Internet has been addressed in the literature 2, 8. Related information can also be easily obtained visiting the under mentioned web pages and other such websites.

Table 4: Sources of Information

http://www.maps.esri.com	http://www.landdata.gov.bc.ca
http://www.intergarph.com	http://www.mapquest.com
http://www.Mapinfo.com	http://www.blm.gov/gis/nsdi.html
http://www.geocomm.com/channel/webmap/	http://gislounge.com/ll/webgis.shtml
http://www.bisindia.org	http://www.biospec.org
http://www.gis.esri.com	http://www.giscafe.com/
http://www.web-mapper.com	http://maps.intergraph.com/GWMDemo
http://gislounge.com/ll/webgis.shtml	http://www.oracle.com
http://www.nsdiindia.org/	http://map.sdsu.edu/gisbook/

Conclusion:

Internet GIS has emerged and is rapidly growing technology. Integrating GIS with Internet is an inevitable trend of the future in GIS community. It is important for the GIS community to monitor and define the course of its development and deployment. JAVA base application development offers object oriented and platform independent characteristics, which is a revolution for Internet GIS. It is essential for Internet GIS to be able to take advantage of the distributed processing to access analysis models and distributed data on the network in order to achieve high interoperability. It is also desirable for end users to be able to download and save data in his/her local machine. For Java to be the programming language of Internet GIS, these issues have to be resolved. However, apart from bandwidth constraints, the technology involved in web applications offers some unique challenges for application developers more research and case studies are required to wide the horizon of this important technology. In the client side Internet GIS application development the multi-session handling through Internet browser is also a challenge for GIS community. The spatial database management using relational database management system (RDBMS) and the concept of the geodatabase opens new windows for future development.

Bibliography:

1. Anonymous. 2004. Project report of Biodiversity Information System. Geoinformatics Division, Indian Institute of Remote Sensing (NRSC), Dehradun.

2. Coleman D.J. and John D. McLaughlin, 1997. "Information Access and Network Usage in the Emerging Spatial Information Marketplace," Journal of Urban and Regional Information Systems, spring

3. Green, D.G. 1994. Databasing diversity – a distributed public-domain approach. Taxon 43, 51-62.

4. Hall, Carl L. 1994. Technical Foundations of Client/Server Systems, New York: John Wiley & Sons, Inc.

5. Krol, E. 1992. The Whole Internet User Guide and Catalog. O’Reilly & Associates, Sebastopol CA.

6. Matuschak, Brian J. 1996. "Commentary: GIS is Being Redefined by Current Computing Trends," The Electronic Atlas Newsletter, Vol. 7, No. 9.

7. Nupoor Prasad, Sameer Saran, Harish Karnatak, P.L.N Raju and P.S. Roy an online GIS for forest resource management a precursor attempt, ESRI proceeding six User conferences 2003.

8. Peng, Zhong-Ren and Douglas, D. Nebert, 1997. "An Internet-Based GIS Data Access System," Journal of Urban and Regional Information Systems.

9. Zhong-Ren Peng, Ming-Hsiang Tsou “Internet GIS: Distributed Geographic Information Services for the Internet and Wireless Networks” ISBN: 0-471-35923-8m March 2003.

10. http://www.nsdiindia.org/

11. http://gislounge.com/ll/webgis.shtml

12. http://www.giscafe.com

Source:

Harish Chandra Karnatak, Sameer Saran and P. S. Roy, 2005 “ Spatial services, a click away” article in Geospatial Today Volume 3 Issue 5 pp-42-46 January-February 2005.

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