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 Use Internet as development platform

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 Internet or Intranet Data Clients Server(s) Optional Separate data storage Data

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 Ubiquitous accessing and sharing of information

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 .. - Display - 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 ..

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

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 .. - 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 http://www.esri.com/software/arcgis/arcgisserver

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) - 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 Concierge Shopping 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 www.onstar.com

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