Geographic Information Systems Web GIS

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

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

The Internet

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

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

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

Three types of architectures ► Thin client architecture ► Medium client architecture ► Thick client architecture

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

Three types of architectures Thin client Medium client Thick client

Thin client architecture

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

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

Medium client architecture

Medium client architecture..

► Client - Display and Map Render - requires a plug-in in the web browser ► Server - Element Generator - out of it’s applications and databases

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

Thick client architecture

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

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

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

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

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) DBs) - LBS software (services, base SW)

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)

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

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

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

Conclusion - Trends in GIS

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