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12 PERVASIVEcomputing Published by the IEEE CS n1536-1268/08/$25.002008IEEE

U s e r - G e n e r a t e d C o n t e n t

opnsrMap:Ur-Gnrad sr Map

Mordechai (Muki) Haklay

and Patrick Weber

University College London

The OpenStreetMap project is a knowledge collective that provides

user-generated street maps.

The process o mapping the Earth

accurately was, until recently, thepreserve o highly skilled, well-equipped, and organized individ-uals and groups. For many years,

it was usually the role o surveyors, cartogra-phers, and geographers to map the world andtranscribe it on paper or, since the 1960s, intothe computer. Lewis and Clarks expedition tomap North Americas West, and Lambton andEverests Great Arc expedition to measure India,are just two amous episodes in the history omaps and map making. Each country has an

established national mapping agency chargedwith keeping the national maps accurate andcurrent (or example, the US Geological Surveyand the UK Ordnance Survey).

Less than a decade ago, it was common to as-sume that a person needed a university-level de-

gree to be able to measure theEarth and transcribe the in-ormation on paper or into thecomputer as well as expensiveequipment and inrastructureto support his or her work.

This, however, has changeddramatically over the past de-

cade. On 1 May 2000, US President Bill Clintonannounced the removal o selective availabilityo the GPS signal1 and, by so doing, providedmuch improved accuracy or simple, low-costGPS receivers. In practical terms, this made itpossible to acquire the receivers position withan accuracy o 6 to 10 meters in normal condi-tions, in contrast to roughly 100 meters beorethe switch o. Attempts to develop location-based services predated this announcement2and were based on inormation rom mobile

phone masts or other beacons. However, these

methods hadnt gained much market share ow-ing to their technical complexity and inabilityto provide a universal coverage. In contrast,GPS enabled the development o cheap receiv-ers with good positional accuracy, and, by mid-2001, it was possible to purchase a receiver unitor roughly US$100.3 These receivers helpedmore people than ever beore collect inorma-tion about dierent locations and upload it totheir computers. However, until 2002, when aninterchange standard (GPS eXchange ormat orGPX) was published, manipulating and sharing

this inormation was a complicated task thatrequired computing and data manipulationknowledge. Fortunately, most GPS receiverdevelopers rapidly adopted the GPX standard,and, by 2004, it had become commonplace(www.topograx.com/gpx.asp).

The wide availability o high-quality locationinormation has enabled mass-market mappingbased on aordable GPS receivers, home com-puters, and the Internet. Although a range oprojects based on user-generated mapping hasemerged, OpenStreetMap (OSM) is probably

the most extensive and eective project cur-rently under development. In this article, we re-view the project and provide an overview or thetechniques and methodologies used within it.

opnsrMap BackgrundTechnological changes over the past 10 years,in combination with increased bandwidth andthe ability to provide better tools or collabo-ration, have led to crowdsourcing4a termdeveloped rom the concept o outsourcing inwhich business operations are transerred to re-mote, many times cheaper locations.5 Similarly,

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OctObErdEcEmbEr2008 PERVASIVEcomputing 13

crowdsourcing is how large groups ousers can perorm unctions that are ei-ther dicult to automate or expensiveto implement.

OSM ollows the peer productionmodel that created Wikipedia; its aimis to create a set o map data thats reeto use, editable, and licensed under newcopyright schemes. The project, born

at University College London (UCL) inJuly 2004, was ounded by Steve Coast;although Coast moved on to start hisown company, UCL still supports andhosts the main server inrastructure.As o May 2008, OSM had more than33,000 registered users (with approxi-mately 3,500 currently active contrib-utors), and data contribution growthcontinues to rise quickly (see Figure 1).A considerable number o contributorsedit the world map collaboratively us-ing the OSM technical inrastructure,

and a core group, estimated at approx-imately 40 volunteers, dedicate theirtime to creating and improving OSMsinrastructure, including maintainingthe server, writing the core sotwarethat handles the transactions with theserver, and creating cartographicaloutputs. Theres also a growing com-munity o sotware developers who de-

velop sotware tools to make OSM dataavailable or urther use across dier-ent application domains, sotware plat-orms, and hardware devices.

A key motivation or this project is toenable ree access to current geograph-ical inormation where, in Europeancountries, accurate digital geographicalinormation is considered to be expen-sive and out o the reach o individu-als, small businesses, and communityorganizations. In the US, where basicroad inormation is available through

the US Census Bureaus Tiger (Topolog-ically Integrated Geographic Encodingand Reerencing)/Line program, thedetails provided are limited to streetsand roads only; it doesnt include greenspace, landmarks, and the like. In ad-dition, owing to the high cost o map-ping, the Tiger systems update cyclesare inrequent and dont take into ac-

count rapid changes. Commercial geo-graphical inormation products romproviders such as NAVTEQ are alsoexpensive and arent available or indi-vidual users in an accessible ormat.

The OSM projects hub is the mainOSM Web site (www.openstreetmap.org), which contains our parts. Visitorsare rst greeted with a Google Maps-style online mapping interace, whichlets visitors pan, zoom, and search theOSM world map and discover whichgeographical areas are completed. An

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Figre 1. Grap o ser an ontribtions growt to OSM on a montly basis. Te grap sows te aelerating growt in

nmber o sers an te rapi inrease in ata entry measre in tra points (sore: ttp://wii.openstreetmap.org).

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14 PERVASIVEcomputing www.opue.og/pevasive

User-Generated Content

export unction allows users to down-load portions o the OSM inormationin dierent raster and vector ormatsor urther use or processing. The edit-

ing tab allows anyone to contribute tothe project by digitizing geographicaleatures, uploading GPX traces romhand-held GPS units, or correcting er-rors they might have discovered in theirlocal areas. The OSM community wiki,open or all registered users, containsinormation about the project and o-ers guidance on best practices to ca-sual and advanced mapping contribu-tors and an extensive documentation othe projects technical inrastructure.

Noticeably, OSM decided to ollowthe route o allowing only registeredusers to edit the map, not ollowingWikipedias open-or-all approach.OSM project leadswanted the abilityto trace the inormation source in caseo copyright disputes and ensure the in-ormation was maintained.

In the ollowing sections, we describethe OSM GeoStack the set o toolsthat lets users capture, produce, com-municate, aggregate, and consume the

geographical inormation produced inthe project (see other work6 or urther

discussion o the GeoStack). As alreadynoted, the Web site provides a mecha-

nism to consume OSM data but inthe next section we move to the startingpoint o the stack, where data is cap-tured and produced.

ediing tlUser-contributed geographical inorma-tion is obviously a core part o OSM,and the OSM developer community hasmade a considerable eort to implementtools to acilitate user contributions tothe database. For most casual contribu-tors, the OSM Web site oers a light-

weight online Flash-based editor, Pot-latch, which lets users add, update, ordelete geographical eatures through arelatively easy-to-use interace. The in-

terace is kept deliberately simple, withmore advanced unctionality providedthrough keyboard shortcuts; Potlatchgives extensive guidance to users byproviding predened tagging schemasor requently occurring eatures (suchas motorways or primary roads).

Potlatch also lets users upload andintegrate GPX tracks recorded romhandheld GPS units. Other importantdata sources rom which users traceroad networks and other eatures is

satellite imagery and out-o-copyrightmaps, which are integrated into themapping interace. Notably, at the endo 2006, Yahoo granted OSM the rightto use its satellite imagery Web serviceto trace roads and other eatures. Forexample, Yahoo hosts detailed aerialimagery o Baghdad, Iraq, which letOSM contributors remotely map thecity in great detail, resulting in the mostdetailed online map o Baghdad to date.However, this map is based solely on

amateur image interpretation, and, de-spite the original eort, very little ur-

ther inormation (such as street names)has been added to the map.

More experienced OSM contributorsalso use the Java OpenStreetMap Editor(JOSM), an editing suite with an inter-ace more akin to traditional geographi-cal inormation systems (GIS) packages.The application lets users import, edit,and tag OSM data ofine and allowsbulk uploads o OSM updates throughthe OSM application programming in-terace (API). JOSM oers advancedunctionalities such as linking OSMeatures to photos and audio notes,supports data confict resolutions, and

can be extended using several indepen-dently developed plug-ins. Exampleso user-contributed plug-ins includecustom Web mapping service (WMS)

background imagery and Yahoo aerialimagery, live recording o external GPSdata, and a data and tagging schemevalidation tool, to name just a ew.

Apart rom individual user contribu-tions rom GPS tracks and the digitizingo aerial imagery, OSM has also takenadvantage o the availability o ree geo-graphical inormation in certain partso the world. For example, over the pastyear, US contributors have imported thepublic-domain Tiger inormation, add-

ing to OSMs comprehensive street andhighway coverage or the entire US.In July 2007, commercial navigationinormation provider AND (Automo-tive Navigation Data) donated the en-tire street map o the Netherlands tothe project, thus completing street-levelmapping o the rst country in OSM.Local and national authorities havecontributed inormation to the projectas wellor example, the Isle o MansDepartment or Local Government and

the Environment donated geographicalinormation to OSM, enabling the cre-ation o an excellent map o the island.

tchnical InfrarucurThe next element o the GeoStack o-cuses on the way in which geographi-cal inormation is stored and orga-nized. Here, at the core o OSM datamanagement, its easy to see how opensource philosophy permeates the proj-ects technical inrastructure. OSM is

built iteratively using the principle thatthe simplest approach to any problemis the best way to ensure the success othe project as a whole. OSMs develop-ers deliberately steered away rom us-ing existing standards or geographicalinormation rom standard bodies suchas the Open Geospatial Consortium(OGC)or example, its WMS stan-dard. They elt that most such tools andstandards are hard to use and maintain,citing perormance issues with, or in-stance, MapServer (a popular open

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source WMS) and a lack o adaptabilityo OGC-compliant sotware packagesto support wiki-style behavior.

At the heart o OSMs technical inra-structure lies the central database hold-ing the live data, which is implementedin MySQL. The database schema is de-signed to support wiki behaviors, such asversioning and rollbacks, and keeps cop-

ies o modied or deleted eatures inde-nitely. All geographical entities are re-corded as points (nodes), which containthe latitude and longitude coordinatesalong with user name and timestampinormation. Linear and area eaturesare dened by reerence to a list o or-dered nodes, called ways. Area eaturesarent explicitly dened in the databaseschemarather, theyre deined im-plicitly by the condition o a way thatsclosed (the rst node o a way is the same

as the last one) and explicit tagging con-ventions (using the tag area=yes).

Along with the geographical coor-dinates o eatures in the OSM data-base, attributes o eatures are recordedor each node and way as semicolon-separated key=value pairs (or exam-ple, type=pub;name=The Bull). This taggingschema, which is increasingly beingdeveloped into a complex taxonomy oreal-world eature classes and objects,is a core part o the OSM initiative and

is community-driven. Any member othe community can contribute to andupdate the schema by proposing newkey=value pairs. Discussion on the OSMwiki leads the community to vote ontag propositions and reach a consensuson the denition o and best practicesor eature tagging. Interestingly, andsometimes controversially, the OSMdatabase doesnt pose any limitationson the tags users can attach to eatures,and thus adhering to the core taggingschema the community agreed upon

is voluntary. Guidance on best prac-tices or tagging is given at the editingsotware level or casual contributors.

The lack o restrictions also benets us-ers because they can reely implementcustom tagging schemas or speciicapplications.

Access to the core OSM database isprovided by a dedicated RESTul API,which is implemented in Ruby on Railsand supports authentication, enablingusers to add, update, and delete geo-graphical eatures. The API acceptsand outputs data in OSM XML, a dedi-cated data transport ormat developed

or the project that replicates the data-bases specic entity model. All editingtools use this API or accessing and up-dating the main database. As a result,editing and presentation tools can bedeveloped independently rom the data-base, with the lightweight communica-tion protocol acting as a glue betweenthe elements o OSMs GeoStack.

Mapping oupuGiven the database, which contains allthe geographical inormation and attri-

butes OSM contributors have collected,the main cartographic output rom theOSM inormation is presented on the

OSM Web site as a Google Maps-likeinterace, coined Slippy Map, whichuses the open source AJAX libraryOpenLayers to dynamically update themap display and allow interaction withusers. As users drag the map, the vis-ible extent is updated and new map tilesare requested in the background with-out reloading the entire HTML page.A search unction (implemented as anexternal Web service) lets users quicklynd cities, villages, or other points o in-

terest (POIs) in the database. Recently,OSM developers added an export tab,which lets users quickly generate mapimages, PDF les, and raw data down-loads o custom bounding boxes.

The deault set o tiles on the mainOSM Web site (see Figure 2) is renderedusing Mapnik, an open source libraryor generating high-quality map images.It usesa weekly database dump as thesource or the rendering o map tiles,given that live rendering o tiles on clientrequest would be too computationally

Figre 2. Main OpenStreetMap Web

site Slippy Map wit etaile overage

o entral Lonon. Notie te ability

to eit, export, an ploa ata

by sing te top tabs (sore: www.openstreetmap.org).

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expensive to be practical; map tiles arethereore rendered or all zoom levelsand saved on the server so that they canbe served rapidly as static images.

Owing to the open source nature oall the tools needed or map render-ing, several OSM contributors havedeveloped custom map tile sets thatcater to specic needs and target au-diences. One example is a tile set thathighlights cycle-path networks andother eatures relevant to cyclists.

Because o the high demands on com-puting during rendering, a communitygrid element o OSM has developed.Tiles@Home (T@H) is a distributed

map-tile-rendering system that com-prises a central coordinating server andapproximately 100 active sotware cli-ents (as o May 2008), which members othe OSM community contributed. Themain server distributes rendering jobsbetween clients, which collect the rele-vant data rom the OSM API and rendera set o map tiles that are then uploadedback to the server or distribution. Themain benet o T@H is that it distributesthe computational load between multi-

tudes o clients, enabling the system toquickly render large numbers o up-to-date map tiles. T@H is especially use-ul or OSM mapping contributors thatwant to quickly see the results o datachanges, as they can request specic ar-

eas to be added to the T@H renderingqueue. Typically, such requests or up-dated map tiles are ullled in a mattero hours, in contrast to up to seven daysor a Mapnik tile set update.

Users interested in only a small areaand who dont need a Web-mappingserver set-up can use local sotwarerendering packages such as Kosmos

or Gosmore to generate maps quickly.Other members o the OSM communityare also developing import and conver-sion tools to support OSM data in GIS

packages such as Maniold GIS (www.maniold.net) and ArcGIS (www.esri.com/sotware/arcgis/). Signiicantly,vendors o commercial GIS packages,such as CadCorp SIS and Global Map-per, have recently included OSM XMLdata support out o the box.

Users have converted OSM inorma-tion or use on a multitude o devices,including mobile phones, PDAs, andGPS units. A community-maintainedsotware package lets users trans-

late OSM data into the Garmin IMGGPS map ormat, despite this or-mats proprietary nature and lack odocumentation.

scial CllabrainUnlike Wikipedia, on which individu-als create the majority o content at dis-parate locations, the OSM communityorganizes a series o local workshops(called mapping parties), which aimto create and annotate content or local-

ized geographical areas. These eventsare designed to introduce new users andcontributors to the community with thehands-on experience o collecting, pro-cessing, and uploading data to the OSMproject. The meetings might take the

shape o inormal and small gatheringsor a ew hours to complete missing ea-tures o a small dened neighborhood,up to more ambitious eorts that takeseveral days and involve several dozenso participants. One o the rst mappingparties took place on the Isle o Wight,o the south coast o England, in May2006. More than 30 participants rom

Europe spent two days driving, cycling,and wandering around the island withGPS receivers to collect a complete cov-erage o roads and ootpaths. Ater col-

lecting the individual contributions,processing them, and uploading thedata, a practically complete map o theisland emerged.

Although these community eventspositively contribute to the overall proj-ect by generating new data and streetlabeling, they arent only meant as datacollection exercises. Mapping partiesplay an essential part in creating and os-tering local OSM user groups and creat-ing a vibrant social community around

the project (see Figure 3). User groupshave now ormed all over the UK, aswell as in continental Europe and therest o the world. A detailed discussiono a mapping party appears elsewhere.7

Mivain and ChallngOSMs success should be attributed toits ounders vision o the project as acombined social and technical chal-lenge. In many interviews and presen-tations, Coast emphasizes the social

sides importance: A big aspect ogetting OSM o the ground was themapping parties: getting drunk andarguing with people.8 Nick Black,another OSM core contributor, notedthat people have a range o reasons orgetting involved in the projectromcertain ideological views such as a be-lie in the provision o ree inormationto improve the world, to anti-nationalmapping agency views, to those whoenjoy going out and mapping or sitting

at home and writing computer code,to those who enjoy eeling like part oa community.9 Coast also adds thattheres an addictive aspect o gettinginvolved in the project, which adds tothe participants commitment.

Indeed, OSM can boast signicantachievement and is currently goingthrough a period o rapid growth interms o the number o users who con-tribute to the map, its visibility as theleading Open Geodata project, and othe number o map edits. Its inrastruc-

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ture is demonstrating how a modern,open source, and light structure canprovide a reliable and scalable GIS; theinnovation that OSM oers can alsoteach many established GIS providersvaluable lessons. The mainstream GISliterature has already noted and dis-

cussed OSM and similar activities.10Along with these achievements, some

open issues still must be taken into ac-count, such as the tness or purpose oOSM data, the infuence o geographyand participation on the project, theability to continue to update the inor-mation, and licensing.

Since early 2007, with the completiono the mapping o Cambridge, OSM in-ormation and the cartographic abilityo Mapnik demonstrated the useul-

ness o the inormation or several car-tographic products and presentationo paper maps.However, this cover-age isnt universal. Although, as Coastnotes, its important to let go o theconcept o completeness,8 some ideaabout inormation quality is crucialor evaluating how t OSM data is orvarious applications. Considerationsthat should be included are how wellan area is covered by data, the datasaccuracy in terms o positional accu-

racy and attributes, the consistencyin terms o classication or data-cap-ture procedures, and quality control.Currently, OSM doesnt provide anyo these measures and doesnt have in-ternal quality assurance procedures.Preliminary results rom an evaluationo completeness at UCL suggest thatOSM has covered about 29 percento roads in England. Even in London,where the project started, large areasare undermapped.

In many applications, attribute inor-

mation, such as trac directions andrestrictions or street names, can be cru-cial. Although data capture based onaerial imagery sped up road mapping,the road name cant be captured with-out a survey at the ground level unlessthe surveyor breaks copyright laws anduses an existing map to copy the name.Furthermore, mistakes rom misinter-preting aerial imagery also must be

rectied through ground survey. Here,theres no escape rom the worldsphysical geography, and OSM is de-pendent on willing contributors on theground in the area under survey. Thesame is true or updates and changesto the dataor example, when a roadchanges rom two-way to one-way ow-ing to local trac regulations.

Although the common argumentrom OSM advocates is that because othe datas ree nature, people who spot a

mistake are likely to be more motivatedto rectiy it, in practice, OSM is exhib-iting the same participation inequalityas many other user-generated contentprojects.11 A ew users are responsibleor contributing a signicant amounto the inormationthis phenomenais also visible in terms o places, wheremany areas are mapped by a singleuser. Its reasonable to assume that,as on Wikipedia, the number o userswho dont contribute any improvementto the map can reach 99.8 percent, to

which the complexities o adding orupdating data to OSM due to the us-ability o the data entry application andthe need to understand the ontologicalschema need to be added. In short, thisis a challenging aspect that the OSMcommunity must solve.

Finally, the issue o licensing has be-deviled OSM rom the start. The proj-ect started with the Creative Commons

ramework (CC-By-SA), which hasproved to be unsuitable or geographicalinormation. For example, the sharealike principle means that by mixingOSM inormation with other sourceso inormation, the resulting map mustbe shared under the same terms. How-ever, OSM creates the base map, whichin most geographical analysis projectsis the starting point. The map is aug-mented either through cartographicprocessing to produce products such as

tourist maps or combined with othersources o inormation, such as the cen-sus, to create thematic maps. It can alsobe combined with sensitive commercialinormation or analyzing store loca-tions, among other things. In all thesecases, the CC-By-SA prevents the useo the data or might complicate matterssignicantly. The OSM community hasbeen discussing a new license or morethan two years and hopes to publishone soon, although its clear that someuse issues will remain unresolved.

Figre 3. A mapping party. In Febrary

2008, Syler Erle an Miel Maron,

ontribtors to OSM, el a series o

mltiay mapping parties in several

niversities to reate loal ontribtorgrops (sore: www.fir.om/potos/

tags/reemapinia2008/).

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OSM provides a good ex-ample o the social andtechnical aspects o user-generated content com-

munities. Using terminology oundin other work,12 OSM is a knowledgecollective that creates Open Geodataas its main objective. Simultaneously,it includes a peer production network,as dierent groups within the organi-zation are developing dierent aspects

o the projectdigitizing tools, map-rendering sotware, server sotware,and running activities such as mappingparties. Its utilizing community com-puting grids in the process o render-ing map tiles through T@H. OSM usessocial mobile computing, especiallyduring mapping parties when partici-pants coordinate their work via mobileGPS receivers and mobile phones. Thegroup-orming network appears on themain wiki, which contains inormation

about the project, and also through anarray o active mailing lists, Web o-rums, Internet Relay Chats (IRCs), andother modes o computer-mediatedcommunication (CMC). Finally, socialaccounting is evident in OSMor ex-ample, in the contributions o variousmembers o the OSM community high-lighted on a Web site about the amounto computing theyve contributed orhow many edits theyve perormed dur-ing the last week, month, and year.

OSM also demonstrates some impor-

tant aspects in terms o geographicalinormation delivery. The data ormatand structures demonstrate a simpleapproach or developing and deliveringgeographical inormation, in contrastto current practice within the GIS in-dustry. On the other hand, OSM dataisnt complete or consistent across theworld, or even across London, wherethe project started. The datas accu-racy is unknown, given that there are

no systemic and comprehensive qual-ity assurance processes integral to thedata collection. Furthermore, theresno intention o universal coverage; asCoast remarks: Nobody wants to docouncil estates. But apart rom thosesocioeconomic barriersor placespeople arent that interested in visitinganywaynowhere else gets missed.9

Although the OSM project startedin 2004, its still in its early stagesthearea o user-generated geographical in-

ormation will surely grow in the uturewith applications in the private, public,and voluntary sectors. It has alreadyshaken the world o geographical inor-mation, and the wider industry is payingattention to the emerging business mod-els that OSM volunteers have created.

AckNOWLEdGMENTS

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vieusefulsuggesionsonanealievesion

ofhisaile.thanksoheroyalGeogaphialSoieysSallreseahGanspoga,whih

povieealysuppofoheengageenof

OpenSeemapin2006.

REFERENcES

1. B. Clinton, Improving the Civilian GlobalPositioning System (GPS), Oce o Sci-ence and Technology Policy, ExecutiveOice o the President, 1 May 2000;http://clinton4.nara.gov/WH/EOP/OSTP/html/0053_4.html.

2. A. Giordano, M. Chan, and H. Habal, ANovel Location-Based Service and Archi-tecture, 6th IEEE Intl Symp. Personal,Indoor, and Mobile Radio Communica-tions, Wireless: Merging onto the Infor-mation Superhighway (PIMRC 95), IEEEPress, 1995, pp. 853857.

3. J. Hightower and G.A. Borriello, Sur-vey and Taxonomy of Location-SensingSystems for Ubiquitous Computing, UWCSE 01-08-03, Dept. o Computer Scienceand Eng., Univ. o Washington, 2001.

4. J. Howe, The Rise o Crowdsourcing,Wired, June 2006; www.wired.com/wired/archive/14.06/crowds.html.

5. T.L. Friedman, The World Is Flat: A BriefHistory of the Twenty-First Century,Updated And Expanded Edition, Farrar,Straus, and Giroux, 2006.

6. A.J. Turner, Introduction to Neogeogra-

phy, OReilly Media, 2006.

7. C. Perkins and M. Dodge, The Potentialo User-Generated Cartography: A CaseStudy o the OpenStreetMap Project andMapchester Mapping Party, North WestGeography, vol. 8, no. 1, 2008, pp. 1932.

8. GISPro, The GISPro Interview withOSM Founder Steve Coast, GIS Profes-sional, no. 18, Oct. 2007, pp. 2023.

9. N. Black, OpenStreet MapG eo-data Collection or the 21st Century,presented at the AGI annual coner-ence, 2007; www.slideshare.net/nickb/nick-black-openstreetmap-geodata-collection-or-the-21st-century.

10. M.F. Goodchild, Citizens as VoluntarySensors: Spatial Data Inrastructure in theWorld o Web 2.0, Intl J. Spatial DataInfrastructures Research, vol. 2, 2007,pp. 2432.

11. J. Nielsen, Participation Inequality:Encouraging More Users to Contribute,Alertbox, 9 Oct. 2006; www.useit.com/alertbox/participation_inequality.html.

12. A. Saveri, H. Rheingold, and K. Vian,

Technologies of Cooperation, Inst. orthe Future, 2005.

heAuThORS

Mordechai (Muki) Haklayisasenioleueingeogaphialinfoaionsieneinhedepaenofcivil,EnvionenalanGeoaiEnginee-

ingaUnivesiycollegeLonon.Hiseseahineessaeinpuliaessoenvionenalinfoaion,huan-opueineaion,usailiyenginee-

ingfoGIS,anhesoiealaspesofGISuse.HaklayhasaPhdingeoga-phyfoUcL.HesaeeofheAcm,afellowofheroyalGeogaphi

Soiey,anaeeofheAssoiaionfoGeogaphialInfoaion(AGI).

[email protected].

Patrick Weberisahi-yeaengineeingooaesueninUnivesiycollegeLononsdepaenofcopueSiene.Hiseseahineesslie

inheappliaionofGIsieneanspaialeisionsupposysesogain

aeeunesaningoffoeignieinveseninLononaswellashewieaessiiliyanpuliawaenessissuesfogeogaphialinfoaion

siene.WeehasanmSinGISfoUcLananmSinphysialgeogaphyfoheUnivesiLouisPaseu,Sasoug.conahiap.wee@ul.

a.uk.

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