|
|
|
Web mapping solutions
Dr. Aniruddha Roy
ESRI India, NIIT GIS Ltd.
New Delhi 110019
aroy@niit.com
Internet GIS software should support a range of configurations that support a diverse set of hardware and networking architectures.
Internet is unleashing profound changes in the society.
Average selling price of PC has been sliding for 30 months
in a row after 16 years’ stability. The top reasons for 85% of individual PC buyers presently are Internet. Applications like mail, searches etc. have more users than any Office suite of applications. This Internet revolution has resulted into the competition amongst the businesses to provide as much as information to the end users in a lucid and illustrative manner.
Map making and geographic analysis are not new, but a GIS performs these tasks faster and with more sophistication than traditional manual methods do. While the most common product of a GIS is often presented in map form, the real power of GIS lies in its ability to analyse.
Without owning the individual software, the Internet GIS technology has opened new paths for disseminating, sharing, displaying, and processing spatial information on the Internet. Web-based solutions provide a low-cost, efficient way to deliver map products to users.
The most common queries people would like to pose in the Internet using GIS functionality are for location display. Next popular event in the Internet is to show the driving directions along the streets. This routing information shows the shortest distance by time and distance impedances for a city and the information is updated regularly based on the traffic conditions like www.mapquest.com. There are sites like www.weather.com wherein one can see the low orbital satellite data showing weather condition and this gets updated every one hour. The users can see the dynamic changes of weather using the interactive player for last several hours. The latest of all the applications, in Internet is for the users to access GIS data at the browser end and integrate that with local specialised application data of their own residing in the local machine. This is now changing the entire model of working with GIS.
Internet Map servers
The first known geographic web site is that of Xerox (mapweb.parc.xerox.com/map) which was established in 1993. It is the world map that has been put in this site with options for many zoom levels. It is not with any true Internet map server but the site had pre-created a large number of different image maps for each case scenario So the request finds the particular html page containing the map and displays it back to the browser. However this was the good beginning and shown lights to several organisations to come forward to show their ability.
As the first to launch Geographic Information System (GIS) capabilities on the World Wide Web, using the middleware program, Internet Map Server (IMS), ESRI (Environmental Systems Research Institute Inc.) built its next generation Internet GIS based on years of expertise. Internet map server is also a very efficient way to make live GIS products available to a large population at minimum cost.
The initial release of the ArcView IMS ver. 1.0 from ESRI has been appropriately used by the Andhra Pradesh Roads and Building department, Government of Andhra Pradesh in 1997-98 for display of the road segments of the Andhra Pradesh with details of the type of the road, road condition, contractor for a certain stretch, engineer responsible for the task etc. That was indeed the first successful Indian Internet GIS project. The application was developed in ArcView GIS and served using extension product Internet Map Server using HTML.
To support the developers who have built their own custom built GIS application in MapObjects using Visual Basic, Visual C++, Delphi, Borland C++ Builder, Visual FoxPro, and Power Builder the Weblink facility was provided in the software MapObjects IMS 2.0.
ArcIMS 3.0 the third generation IMS product from ESRI has flavour of both desktop applications like ArcView GIS and developers choice of customising the same. It can serve in diverse applications as e-commerce, location based services, Enterprise Resource Planning (ERP) etc. The installation is simple wizard based with several standard templates for ready to use application. The MapMachine site is accessible to anyone with an Internet connection (www.nationalgeographic.com) and provides dynamic thematic maps, showing natural and human phenomena at a global scale using ArcIMS 3.0 internet GIS software. The GIS data is more than 150GB to support the generation of more
than 500,000 customised, GIS-based maps every day.
System Design Architecture
To create an Internet GIS application and serve that on the net, primary factors like the type of GIS functionality, downloading time into the client browser and the cost of the whole application are considered. System design solutions must be based on user requirements. GIS environments require customer investment in people, data, applications, and hardware resources. It is important to make appropriate investments in each of these resources for GIS operations to be successful. The success of the GIS operations will be limited by the weakest component within the total solution. All the other software, hardware, and network components in the system must also be capable handling any expansion. The importance of selecting well-established software solutions and optimising all the system components cannot be overemphasised since all parts of the distributed configuration are critical in supporting the system’s overall performance.
After the GIS users, data requirements, and application strategy are identified, an appropriate software, hardware and network infrastructure can be defined to support GIS implementation. The general guidelines for the same is described below:
Software
Internet GIS software should be hardware independent. As hardware manufacturers and technologies change over time and some manufacturers provide better functionality, performance, or communication capabilities as time evolves, the end user should look for the software that support multiple platforms. It should continue to support a wide variety of hardware platforms and to take full advantage of improvements in hardware, communications, networking, and database functionality, as they become available. The software should be in a position to support both Windows NT/Windows 2000 and also UNIX platforms.
The best system architecture design solution depends on the distribution of the user community and the type of operational data in use. A single map server can service hundreds of map products per hour to clients with standard Internet browser software. GIS products can be easily distributed to every desktop in an organisation (through the Web server), and to the general public through World Wide Web communications.
|
|
|