Department of Geo-information Processing possibilities & pitfalls of web sites for spatial data dissemination Barend Köbben International Institute for Geo-information Science and Earth Observation (ITC)

Department of Geo-information Processing Setting the stage Barend Köbben

Department of Geo-information Processing Overview Why use maps? Changing Cartography Why use the Web? WebCartography:  static ‘view-only’ web-maps  static ‘interactive’ web-maps  dynamic ‘view-only’ web-maps  dynamic ‘interactive’ web-maps How the Web works

Department of Geo-information Processing Why use graphics? Graphics are international: uitgang, exit, Ausgang, sortie, uscita, salida,etc... =

Department of Geo-information Processing Why use graphics? Graphics are holistic: “a picture says more than a thousand words...” “First road left, then cross the railroad and continue until you cross the river, then the first right and right again on the crossroads...”

Department of Geo-information Processing Why use maps? rainfall 12, 13, 14 september dirksland de bilt apeldoorn

Department of Geo-information Processing Why use maps? apeldoorn de bilt dirksland

Department of Geo-information Processing Why use maps? Maps give an instant and complete overview of spatial phenomena

Department of Geo-information Processing Developments in cartography  1950’s first computer maps  1960’s / 1970’s automation of existing tasks (line drawings)  1980’s computer-assisted map production  1990’s full integration of maps in GI (scientific) visualization from supply to ‘demand’ driven mapping Internet / Web environments  2000’s location-based services in mobile environments

Department of Geo-information Processing CHANGING CARTOGRAPHY  new kinds of maps Interactive maps Realism & false realism: Virtual worlds Depiction of movement & change: Animated maps Combining maps with other graphics, sound and moving images: Multimedia

Department of Geo-information Processing Traditional vs. interactive maps traditional map = view only map  bitmaps (scanned images) interactive map (map as interface)  clickable map: leads to other (web) information; map as menu; interactive map (user–defined contents)  maps on demand; user defines contents and/or symbolisation

Department of Geo-information Processing Interactive maps

Department of Geo-information Processing The world mapped “as it is” Perspective view (instead of orthogonal) Complete (not generalised) Realistic (not symbolised) Photo–realism (or pseudo–realism) Virtual worlds

Department of Geo-information Processing Virtual Worlds

Department of Geo-information Processing Animated maps For showing dynamic phenomena  As animated maps (“movies”)  As dynamic real-time images (dynamic webpages) For moving through Virtual Worlds  As animations (eg. animatedGIF, Quicktime movies)  With interactive contents (modelled worlds, eg. games, VRML)

Department of Geo-information Processing Multimedia definition “The combination of various media parts into a coherent whole” Media parts:  maps, graphics, text, moving images, sound, text, etc... Coherent whole:  The whole is more than the sum of the parts

Department of Geo-information Processing On CD–ROM On the World Wide Web: a distributed, inter-linked collection of data + protocols to publish and retrieve this data (http, html, etc...) CHANGING CARTOGRAPHY  new (digital) data dissemination

Department of Geo-information Processing Why use the Web? WWW information is virtually platform- independent unrivalled in its capacity to reach many users at minimal costs easy to update frequently the WWW allows for a dynamic and interactive dissemination of spatial data:  New map types

Department of Geo-information Processing Disadvantages Potential user group is limited (though growing fast) and skewed (computer- literate and connected people) Difficult to charge for use Fast-moving:  Information is time-sensitive  Interactivity is a must

Department of Geo-information Processing World Internet users Pie slices show regional shares of world population. Dark wedges show Internet users (numbers indicate Internet users as a percentage of the total population per region). Internet users of total world population: 5.7 % [UNDP 2000]

Department of Geo-information Processing Technical constraints Map and file size  Screen size & resolution  Download times File formats  Standardised: GIF & JPEG (raster), SVG (vector) Colour use  Only 216 “web-save” colours  Special map design needed

Department of Geo-information Processing WebCartography Some examples Further examples: Webcartography/index.html Further reading: Kraak, Menno-Jan & Allan Brown (eds) (2001): Web Cartography, developments and prospects, London and New York: Taylor & Francis

Department of Geo-information Processing WebCartography

Static maps – view only Existing maps (scanned)  mainly interesting for Historical maps Specially designed web- maps  eg. cartography students at ITC

Department of Geo-information Processing Static maps – interactive interface Map is entrance to other (map) information: ‘clickable maps’  HTML clickable maps (Netherlands in provinces) (Netherlands in provinces)  Flash maps of Overijssel (data, magnify) (data, magnify) User can change map content & visualisation:  from simple layers on/off… map of Overijssel (Flash) map of Overijssel (Flash)  …to fully interactive Tuerlersee topographic map (SVG) Tuerlersee topographic map (SVG)

Department of Geo-information Processing WebCartography

Dynamic web maps For showing dynamic phenomena  As animated maps (‘movies’) (eg. gondwana) (eg. gondwana)  As dynamic real-time images (ANWB)ANWB

Department of Geo-information Processing Dynamic web maps For moving through Virtual Worlds  As a view-only animation (eg. animated GIF)  With an interactive interface (“movie”) (eg. quicktime) (eg. quicktime)  With interactive contents (modelled) (eg. games, VRML)VRML

Department of Geo-information Processing Web graphics today standardised raster formats:  fixed resolution (quality low or files large)  original content (“information”) is lost  difficult to get interactivity (other than ‘clickable maps’)  binary formats (no searching/indexing of information, no internationalisation) W3C standardised: GIF, JPEG non-standard industry (proprietary) formats  raster or vector; offering diverse, possibilities Countless examples, eg: PDF, Flash

Department of Geo-information Processing Web graphics of the future: vector graphics, resolution-independent "content" of information saved client-side ‘rendering’ -> customisable for viewing environment XML-based  W3C’s designated backbone for the future Web

Department of Geo-information Processing XML (eXtensible Markup Language)  not a fixed format, but a ‘metalanguage’ —a language for describing other languages—  lets you design your own customized markup languages for limitless different types of documents  eg. Geographic Markup Language (GML) - OpenGIS standard for geographical information  written in SGML (the international standard metalanguage for text markup systems; ISO 8879)  much more than a webpage language  useable for storing and exchanging any kind of structured data

Department of Geo-information Processing Scalable Vector Graphics (SVG) graphic quality  2D vector graphics + in-line raster (jpeg, gif, png)  all anti-aliased scalability  vectors = resolution-independent (zoom, pan)  transformable, user defined ‘coordinate-spaces’ interactivity  declarative (in SVG objects)  procedural (Javascript) animated & dynamic maps  dynamic change of object attributes  declarative syntax (limited file size)  animation client-side

Department of Geo-information Processing Links to examples: VRML model of Ramelerbrink: Flyby Quicktime movie: Interactive application of Gondwana continental drift: Interactive contents (layers on/off) - Flash: Interactive interface (magnifiy) - Flash: Interactive contents (map as menu) - Flash: Interactive interface (map as menu) - HTML: Further examples of WebMaps: Webcartography/index.html Swiss map with LOD: Swiss topographic map of Tuerlersee (hillshade & cross-sections): Morphing of London underground: