Webservices Technological Evolutions Peter Bogaert University of Ghent (Belgium)
Van Mainframe naar een gedistribueerd GIS Geographic Informationsystems From mainframe to distributed systems by means of webservices. P. Bogaert
Platformevolution Time
Accessibility Advantages Actuality
Reach Advantages
Arpanet TCP IP: communication protocol Reach Tim Brenners Lee and the WWW High Perfomance Act + Webbrowsers 1969 1978 1989 1993 1995 users
Users 1200000000 1000000000 800000000 600000000 400000000 200000000 0 June 94 October 95 March 97 Reach July 98 December 99 Time April 01 September 02 1 000 000 000 January 04 May 05 October 06 Source :CyberAtlas
Users 6000000 5000000 4000000 3000000 2000000 1000000 0 July 98 December 99 Bereikbaarheid Belgium April 01 September 02 Time January 04 May 05 October 06 Bron: Insites BIM I XIII
Users 2002 Source :CyberAtlas 2002
Relative number of users 0 5.31 5.31 15.31 15.31 29.65 29.65 50.81 50.81 68.51 No Data Users 2005 Source :CyberAtlas 2005
Alsolute number of users 200 3720000 3720001 13880000 13880001 41880000 41880001 99800000 99800001 185550000 No Data Users 2005 Source :CyberAtlas 2005
Van Mainframe naar een gedistribueerd GIS GIS and the Internet
Data Search and Download
Offer of Information
Data Services
Application Services
Distributed GI System Definition A distributed system is an application that runs on different computers, with different operating systems, at different locations and different connections but for the user it seems to be one system only
Client/Server architecture applied to a GIS Partitioning in software Presentation Logical Data
Client/Server architecture applied to a GIS Partitioning in software: Division point Presentation Logical Data Distributed Presentation Remote Data Access Remote presentation Distributed function Distributed database
Remote Presentation
Remote Data Acces
Client/Server architecture applied to a GIS Two, three, n tier systems
Van Mainframe naar een gedistribueerd GIS STANDARDS
Van Mainframe naar een gedistribueerd GIS XML
XML Van Mainframe Impacts naar of web een gedistribueerd services GIS XML? A language used to describe information Textual : easy to read
3 components Defining component XML
3 components Information component XML
3 components XML Read/Visualise component: Parser
Van Mainframe naar een gedistribueerd GIS Data Storage
GML Geography Markup Language An XML application for modelling and storing Geographic Information
GML Van Mainframe Impacts naar of web een gedistribueerd services GIS GML 2.0 GML 3.0 Simple features: point, line, polygon, no curves 2D GML 2.0 + 3D + Topology + complex features + temporal aspects + Reference systems + 8 times as big
Van Mainframe naar een gedistribueerd GIS Data Transmission
WMS (Web Map Service) Transmission via Images + + =
WMS (Web Map Service)
Functionalities WMS (Web Map Service) Client Data Server GetCapabilities Available Data and Metadata GetMap Image GetFeatureInfo Attribute Information
Client WFS (Web Feature Service) Instead of images, the data itself is sent Data Server GetCapabilities Available Data and Metadata DescribeFeatureType Data Description GetFeature Data
Others Catalog Service for the Web (Metadata)!!! Web Coverage Surface Web Terrain Service Styled Layer Description
Van Mainframe naar een gedistribueerd GIS Services Standards
Service Standards Van Mainframe Impacts naar of web een gedistribueerd services GIS UDDI : Universal Description, Discorvery and Integration Webservices Yellow Pages WSDL : Web Service Description Language Description of a webservice: available operations and parameters SOAP : Simple Object Acces Protocol Communication protocol for the communication between the client and the server of a webservice
Service Standards
Van Mainframe naar een gedistribueerd GIS For Free or For Fee?
For Free of For Fee? Webservices <> Free! Beveiliging mogelijk Copyrights en Privacy
Van Mainframe naar een gedistribueerd GIS Webservices : Users Professional / Non Professional?
Users Van Mainframe Impacts naar of web een gedistribueerd services GIS Professional Time A tailor made job Actuality Non Professional Inform Conversation Simple
Van Mainframe naar een gedistribueerd GIS The Medium
Considerations concerning the medium Client Server Architecture. Client Browser (Internet Explore, Netscape,...) Client Computer Communication Request Answer The connection Server Webserver (IIS, Apache,...) Serving Computer
Considerations concerning the medium Van Mainframe Impacts naar of web een gedistribueerd services GIS Client Computer: Plug ins (available / installed?) Avoid Plug ins Browsers (Netscape, Internet Explorer, Opera,?) Use Standards (HTML / DHTML) Online validation of the code via W3C Screen resolution (800x600 of 1024x768 ) Keep maps small Interactive maps can adapt to the users screen resolution Colours (256 colours or more?) Use with web save colours only (256 standard colours)
Considerations concerning the medium Van Mainframe Impacts naar of web een gedistribueerd services GIS The communication Does the client/server have a broadband/smallband connection How long does it take to use the service (5 seconds) World Wide Web <> World Wide Wait!!!
Considerations concerning the medium Van Mainframe Impacts naar of web een gedistribueerd services GIS The connection Keep the information to be sent as small possible Compression! Use interactivity! Send only the information which is asked for
Considerations concerning the medium Van Mainframe Impacts naar of web een gedistribueerd services GIS The serving computer: Do all systems that generate maps work on my system? (Windows, Unix, Linux, ) Do I have a strong enough computer to cope with: Number of visitors Memory Connection Maps to be generated Storage Memory
Conclusion Van Mainframe Impacts naar of web een gedistribueerd services GIS Technical possiblilities are available The Web : Multimedia Reach Actuality Metadata Privacy Copyrights
Van Mainframe naar een gedistribueerd GIS Geographic Informationsystems From mainframe to distributed systems by means of webservices Peter Bogaert peter.bogaert@ugent.be Ghent University www.geoweb.ugent.be