Impacts of web services web services Impacts of web services. P. Bogaert Ph. De Maeyer

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Approaches Human thinking pattern Technologic aspects

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen.

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. History of GIS computing Accessibility Time

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Evolution of the Internet Arpanet TCP-IP: communication protocol Tim Brenners-Lee and the WWW application High Perfomance Act + Webbrowsers Number of users

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. How many people use the WWW

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. How many people use the WWW Source :CyberAtlas 2005

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. How many people use the WWW Source :CyberAtlas 2005

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. How many people use the WWW? Source :CyberAtlas

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Impact? Advantages of webcartography: facilities for actualisation of data; large diffusion (and quick (!?) diffusion) of the information; interactivity; zooming facilities and multi-window approach; possibilities for creating personalised maps using personal selections of information and map layers and using personalised symbolisations; facilities to integrate multimedia, including sound, animations, …; less limitations of diffusion of large amounts of maps and accompanying information; possibility to deliver a product that is free for customer (all times wished?); …. accessibility –Available worldwide –All you need is a PC and a connection –GSM / Pocket PC –…–… actuality –Almost real-time –But!! Keep information up to date!! interoperability

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Impact ? Disadvantages of webcartography: limited image resolution, but …; limitation in overview and limitation in the covered surface, but …; difficulties for mental mapping; disappearance of copyright concept (fuzzy copyright interpretations by users); legal issues (law and directives for privacy, databases, software, …) language (choice, globalisation) data quality? (origin, completeness, actuality, scale, precision, accuracy and consistency: geometric and semantic)

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Due to Accessibility of Data 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 Distributed GI-System

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Partitioning in software Presentatie VerwerkingGegevens

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Partitioning in software: Division point Presentatie Verwerking Gegevens Remote presentation Distributed Presentation Distributed function Remote Data Access Distributed database

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Partitioning in software Presentation Logicaldata Distributed Presentation Interactivity

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Partitioning in software Presentation Logicaldata Distributed function

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Partitioning in software Presentation Logicaldata Remote Data Acces

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Partitioning in software Presentation Logicaldata Distributed database

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Partitioning in software Thin Thick

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Client/Server architecture applied to a GIS Two, three, n-tier systems

Impacts of web services Exchange standards

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards GML Geography Markup Language is an XML grammar written in XML Schema for the modelling transport, and storage of geographic information. –ISO standard (commision TC211) –Developed by OGC (Open Geospactial Consortium)

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards GML Geography Markup Language GML 2.0 –Simple features: point, line polygon, no curves –2D GML 3.0 –GML 2.0 –+ 3D –+ Topology –+ complex features –+ temporal aspects –+ reference systems + … –8 times as big

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen.

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards WMS (Web Map Service)

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards WMS (Web Map Service) –Exchange of geographic information via images += + …

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards WMS (Web Map Service) –Operations GetCapabilities GetMap (GetFeatureInfo)

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards WFS (Web Feature Service) –Instead of an image, features are send –Allows operations –Answer in GML –Basic WFS vs. Transition WFS

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards WFS (Web Feature Service) –Operations GetCapabilities DescribeFeature GetFeature Transaction LockFeature

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Exchange standards Others: –Catalog Service for the Web (Metadata) –Web Coverage Surface (Coverages) –…

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Considerations concerning the medium Client-Server Architecture. Browser (Internet Explore, Netscape,...) Webserver (IIS, Apache,...) Client Server Communication Request Answer Client Computer The connection Serving Computer

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Considerations concerning the medium Client Computer: –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) –Plug-ins (available / installed?) Avoid Plug-ins –Browsers (Netscape, Internet Explorer, Opera, … ?) Use Standards (HTML / DHTML) Online validation of the code via W3C

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Considerations concerning the medium The communication –Does the client/server have a broadband/smallband connection –How long does it take to view the map (5 seconds) World Wide Web <> World Wide Wait !!!

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Considerations concerning the medium The connection –Keep the information to be sent as small possible –Compression! –Use interactivity! Send only the information which is asked for

Impacts of web services AM/FM-GIS Belux - 08 november Grimbergen. Considerations concerning the medium 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 –…

Impacts of web services Thanks Philippe De Maeyer | Peter Bogaert {philippe.demaeyer, Universiteit Gent