1. Geographic Information Systems
Web GIS

2. What is a Web GIS?
Web GIS is an on-line version of geographic information system
Using it, GIS data and functions are made available over the Internet
It is also called Internet GIS, or Online GIS
Use Internet as development platform

3. Client-Server network
A client/server network involves a large number of client computers connecting to a single, central server computer
Servers usually are high speed computers with robust hardware capacity to handle large volumes of client service requests

4. The Internet

5. Basics of Web-GIS Internet or Intranet Data Clients Server(s) Optional
Separate data
storage
Data

6. How does Web GIS work?
Users (clients) submit requests for maps, data, or analysis to a Web server
The server processes the requests and returns requested maps, data, or analysis to the clients

7. Why Web GIS?
Avoid the complicated (and often expensive) GIS software installation in individual client computers
Users can access GIS database and GIS applications from anywhere through a common Web browser
Ubiquitous accessing and sharing of information

8. Three types of architectures
Thin client architecture
Medium client architecture
Thick client architecture

9. Three types of architectures
Thin client architecture
- users only need to display maps
Medium client architecture
- users perform some data manipulation and analysis locally on their own computers, in addition to map display
Thick client architecture
- users perform advanced analysis locally, in addition to map display and simple analysis

10. Three types of architectures
Thin client
Medium client
Thick client

11. Thin client architecture

12. Thin client architecture ..
- Display
- requires a standard browser
Server
- Map Render and Element Generator
- out of its databases and applications

13. Thin client architecture ..
Protocol (primarily for data transfer)
- e.g. raster data transfer
Uses
- map display
Examples:
- Google Map

14. Medium client architecture

15. Medium client architecture ..

16. Medium client architecture ..
- Display and Map Render
- requires a plug-in in the web browser
Server
- Element Generator
- out of it’s applications and databases

17. Medium client architecture ..
Protocol
- encoded vector
Uses
- map display, data query, and simple analysis (measure distance, draw a polygon)
Example:
- Google Earth

18. Thick client architecture

19. Thick client architecture ..
- Display, Map Render, Element Generator
- requires plug-ins and stand alone tools
Server -
- allows for access to its applications and databases

20. Thick client architecture ..
Protocol
- raster, vector, etc.
Uses
- display, data query, and advanced analysis (overlay, buffer)
Example:
- ArcGIS for Server

22. Applications – Location-based Services (LBS)
A location-based service
- an information service provided by a device that knows where it is
LBS include services to identify the location of a person, an object, or a place, such as the nearest ATM machine or the whereabouts of a friend

23. LBS-capable device
Any device that includes a GPS capability, such as a laptop or a smartphone
Can tack postal parcels, vehicles, coupons, etc.
E-commerce, social networks, mobile networks
Web of things, web of people, web of events

24. Required technologies
Key: determine the location of devices
LBS requires technologies to work together
- Positioning technologies (GPS)
- Terminal technologies (cell phones)
- Networking technologies
- Database technologies (indexes, spatio-temporal
DBs)
- LBS software (services, base SW)

25. Required technologies ..
- …
- GIS to
Provide and administer base map data such as man made structures (streets, buildings) and terrain (mountains, rivers)
Manage point-of-interest data such as location of gas stations, restaurants, nightclubs, etc)

26. LBS for Mobiles Emergency Services E-911 Road-side service Directions
Loc-Based Information - Push
Reminders
Traffic / weather alerts
Loc-Based Information - Pull
Concierge
Shopping
City guide

27. LBS for mobiles .. Navigation Directions prior to trip
Enroute planning / recommendations
Tracking
Workforce / Vehicle (fleet/stolen/lost)
Family
Location-Enhanced Imaging
Location info captured with video or sound
Send images with maps
Location Sharing
Friend-finder / landmarks

28. Emergency services Provide one of the strongest motivations for LBS
Problem: users of a cellphone is unable to report his/her current location to enable effective response
A solution: install GPS in the vehicle

29. Conclusion - Trends in GIS

30. Potential of Web GIS
Internet users will be able to access GIS applications from their browsers without purchasing proprietary GIS software
WebGIS will make it possible to add GIS functionality to a wide range of network-based applications in business, government, and education institutions