Department of Geo-information Processing possibilities & pitfalls of web sites for spatial data dissemination Barend Köbben International Institute for

Department of Geo-information Processing

possibilities & pitfalls of web sites possibilities & pitfalls of web sites for spatial data disseminationfor spatial data dissemination

Barend KöbbenInternational Institute for Geo-information Science

and Earth Observation (ITC)


Setting the stageSetting the stage

Barend Köbben<[email protected]>


OverviewOverview

• 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


Why use graphics?Why use graphics?

Graphics are international:uitgang, exit, Ausgang, sortie, uscita, salida,etc...

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Why use graphics?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...”


Why use maps?Why use maps?

rainfall 12, 13, 14 september

dirksland de bilt apeldoorn



apeldoorn

de bilt

dirksland



Maps give an instant and complete overview of spatial phenomena


Developments in cartographyDevelopments in cartography

1950’sfirst computer maps

1960’s / 1970’sautomation of existing tasks (line drawings)

1980’scomputer-assisted map production

1990’sfull integration of maps in GI

(scientific) visualization from supply to ‘demand’ driven mapping Internet / Web environments

2000’slocation-based services in mobile environments


CHANGING CARTOGRAPHY CHANGING CARTOGRAPHY new kinds of maps 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


Traditional vs. interactive mapsTraditional 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


Interactive mapsInteractive maps


The world mapped “as it is”

Perspective view (instead of orthogonal)

Complete (not generalised)

Realistic (not symbolised)

Photo–realism (or pseudo–realism)

Virtual worldsVirtual worlds


Virtual Worlds Virtual Worlds


Animated mapsAnimated 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)


Multimedia definitionMultimedia 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


• 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 CHANGING CARTOGRAPHY new (digital) data dissemination new (digital) data dissemination


Why use the Web?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


DisadvantagesDisadvantages

• 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


World Internet usersWorld 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]


Technical constraintsTechnical 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


WebCartographyWebCartography

• Some examples

• Further examples:http://kartoweb.itc.nl/webcartography/workshop Webcartography/index.html

• Further reading: Kraak, Menno-Jan & Allan Brown (eds) (2001):Web Cartography, developmentsand prospects, London and New York: Taylor & Francis




Static maps – view onlyStatic maps – view only

Existing maps (scanned) mainly interesting for

Historical maps

Specially designed web-maps eg. cartography students

at ITC


Static maps – interactive interfaceStatic maps – interactive interface

Map is entrance to other (map) information: ‘clickable maps’ HTML clickable maps (Netherlands in provinces)

Flash maps of Overijssel (data, magnify)

User can change map content & visualisation: from simple layers on/off… map of Overijssel (Flash)

…to fully interactive Tuerlersee topographic map (SVG)




Dynamic web mapsDynamic web maps

For showing dynamic phenomena As animated maps (‘movies’) (eg. gondwana)

As dynamic real-time images (ANWB)


Dynamic web mapsDynamic web maps

For moving through Virtual Worlds As a view-only animation

(eg. animated GIF)

With an interactive interface (“movie”) (eg. quicktime)

With interactive contents (modelled) (eg. games, VRML)


Web graphics todayWeb 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


Web graphics of the future: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


XML (eXtensible Markup Language)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


Scalable Vector Graphics (SVG)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


Links to examples:Links to examples:VRML model of Ramelerbrink:

http://kartoweb.itc.nl/public_examples/Ramelerbrink_VRML.html

Flyby Quicktime movie:

http://kartoweb.itc.nl/public_examples/flyby.mov

Interactive application of Gondwana continental drift:

http://kartoweb.itc.nl/gondwana/gondwana.html

Interactive contents (layers on/off) - Flash:

http://kartoweb.itc.nl/public_examples/overijssel_interactive_contents.swfInteractive interface (magnifiy) - Flash:

http://kartoweb.itc.nl/public_examples/overijssel_mapmagnifier.swfInteractive contents (map as menu) - Flash:

http://kartoweb.itc.nl/public_examples/overijssel_interactive_interface.swfInteractive interface (map as menu) - HTML:

http://kartoweb.itc.nl/public_examples/Clickable_map_NL_provinces/index.html

Further examples of WebMaps:

http://kartoweb.itc.nl/webcartography/workshop Webcartography/index.html

Swiss map with LOD:

http://kartoweb.itc.nl/public_examples/LOD_CH_SVG/LOD.html

Swiss topographic map of Tuerlersee (hillshade & cross-sections): http://kartoweb.itc.nl/public_examples/Tuerlersee.html

Morphing of London underground:

http://kartoweb.itc.nl/public_examples/UndergroundMorph.html

Documents

Department of Geo-information Processing possibilities & pitfalls of web sites for spatial data dissemination Barend Köbben International Institute for