Collaborative Mapping & Crowdsourcing                       
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by Rob Lemmens and The Google Map Makerpedia team

In Short

Learn the principles of collaborative mapping and crowdsourcing.


Collaborative mapping and crowdsourcing are two methods of generating content on the internet, which involves contributions from a large, disparate group of individuals.  These methods rely upon web applications that allow people to upload information easily and allow many others to view and react to this information. Such web applications are often considered part of Web 2.0.

There are several tools available which allow users to create and edit web content, such as tagging tools, wiki software (Wikipedia),  and web-based spatial data editors (e.g., Google Earth, Google Maps, Google Map Maker, OpenLayers).

Map Content on the Web

A  vast amount of geodata is available on the internet, through on-line maps, web services and virtual globes. Data providers range from the individual mapper enthusiasts to geo-information professionals. Base data, such as road networks and satellite imagery are made available on a global scale, and more specific and valuable thematic data is often produced within dedicated projects.

Current software applications are changing the web to act more and more as platform for real-time information integration, with many web sites collaboratively controlled.  Geospacial applications range from personal mash-ups, which is the combination of data from two or more sources, to project-based web mapping, where the concept of location adds new possibilities for exploring information.  

Google Map Maker is an example of spatially-enabled web technology, which allows for a low cost and fast dissemination of specific geo-information onto base maps, to a smaller dedicated audience, or to the public at large. Information channels range from desktop inputs to SMS messaging. The integration of bulk-input can be managed by dedicated software applications such as Ushahidi, which was successfully used to map inputs from citizens during the 2007-2008 Kenyan crisis and the 2010 Haiti earthquake aftermath.
© 2011 Google

Different Ways of Exploiting Web 2.0

The means of publishing geo-information may differ across projects. These include:
  • Ad-hoc:  Mashups uploaded by individuals, not necessarily meant to be altered by others (Figure 1).   
  • Crowd     sourcing: project-driven improvement of base maps and mashups produced with contributions by the general public
  • Project collaboration within or between organizations: project-related mashups shared by project partners
  • Project documentation & outreach: project-related mashups provided to project reviewers or the general public

Ad-hoc mashup for the event of a beach cleanup day (see the map in Google Maps: beach map) © 2011 Google


Crowdsourcing is a particularly popular means of generating data.  Crowdsourcing relies on the principle that a lot of knowledge resides with individual citizens, who are experts of their own local environment.  Mapping sites that utilize crowdsourcing include: Google Map Maker, OpenStreetMap project, Geo-wiki, and Wikimapia. These tools vary in terms of scope of geographical coverage, data entry methods, targeted end-users, data licensing arrangements, and ease of use.  Additionally, they may use different methods of moderating data (verifying that entered data is valid), which influences data quality and speed of publication.

Spatial Data Infrastructure

In order to more effectively share geodata, organisations may need to develop and institutionalize a Spatial Data Infrastructure.  An SDI is a coordinated series of agreements on technology standards, institutional arrangements, and policies that enable the discovery and use of geospatial information by users and for purposes other than those it was created for.  SDIs facilitate the discovery and integrated use of geo-information across organisations in a standardized way.  They are built at local, national, regional and global scales. Regulations for building SDIs are being endorsed by for example the Federal Geographic Data Committee in the US (FGDC) and by INSPIRE in Europe.


Lesson:  Becoming familiar with the local mapped environment

Objective: This exercise should make you more aware of the power of local knowledge you have.

Group Size:  At least four

Materials: Computer; Internet; Printer; Pen


1.  Go find a computer with internet connection and go to Google Maps (

2.  Switch to Satellite view by clicking on the maps/satellite button in the top right of the screen.  In the drop-down window below unselect labels.

3.  Zoom into the area where you live, so that a number of streets are visible.

4.  Print out the image by making a screenshot (alt-Prtscreen on Windows, Cmd-sht-4 on Mac) or following the print instructions on screen.

5.  Take 10 minutes to draw the streetnames and points of interest (shops, schools, etc.).

6.  Come together in small groups (about 4 fellow students) and discuss the easy and difficult parts of this exercise. Save your annotated image for a later exercise.

Lesson:  Review of crowdsourcing resources

Objective:  Learn more about different forms of crowdsourcing.  

Group Size:  These exercises can be performed by any groups of any size

Materials: Computer; Internet


1.  Look up on the web three crowd sourcing applications that trigger your imagination.

Here are some web sites which can help you finding them, but feel free to search beyond.


For each crowd sourcing application that you find, write down answers to the questions below to characterize the application:
  1. What is the name of the apllication?
  2. Which Web application software(s) is/are used?
  3. Who are the information providers (the crowd)?
  4. Who are the information consumers (an organisation, maybe the same crowd)?
  5. Write down the web resources you used to answer the above questions.

Lesson: Geospatial paper reading assignment and presentation

Objectives: Learn about specific geospatial initiatives; get aware of contextual topics and discuss in depth

Group Size: Four per group preferable; at least two groups total

Materials: Computer; Presentation Software; Papers listed below:

Craglia, M. et al. (2008) Next-Generation DigitalEarth. A position paper from the Vespucci Initiative for the Advancement of Geographic Information Science. In: International Journal of Spatial Data Infrastructures Research, Vol. 3, 146-167.

Man, E. de (2007) Beyond Spatial Data Infrastructures there are no SDIs – so what. International Journal of Spatial Data Infrastructures Research, 2007, Vol. 2, 1-23.

Yang,C., Raskin,R., Goodchild, M., Gahegan,M. (2010) Geospatial Cyberinfrastructure: Past, present and future. In: Computers, Environment and Urban Systems 34 (2010) 264–277.


1.  Divide into groups, select a paper, and set a timeline for completing the project.

2.  Write a review of the selected paper (500-800 words) individually. There should be a general summary (300-600 words), as well as a discussion of the paper’s central message, assumptions, reasoning, and conclusions (200-400 words). With which parts do you agree? With which parts do you disagree?

3.  Submit the abstract to the instructor. This abstract will be assessed.

4.  Discuss the contents of the paper with your group members. Discuss the the central message, the parts with which you agreed and disagreed, and why.

5.  Together with your other group members create a 10 minute presentation discussing your paper.

6.  Read the paper chosen by another group. Prepare together with your group members 3 questions that can be asked and answered during a presentation session.

7.  Present your paper with your group members and answer the questions posed by another group.

Answer Key or Rubric: Determine grade weightings for the paper and presentation.  Grade based on the following quality in addressing:  general summary, assumptions, reasoning, conclusions;With which parts do you agree? With which parts do you disagree?


Base data is the initial data that is used to create or modify a map.

Bulk input is the process of loading or updating multiple entries or datasets into a database.

Crowdsourcing is the use of a large group of people or an established community to complete work traditionally done by an employee.

Collaborative mapping is the collective creation of web maps and user-generated content by a group of individuals.

Geodata is short for geographic information.  

Geospatial describes the geographic positioning of objects or points.

Map-up is an event, usually social,  that fosters collaboration on and creation of map content.

Mashup is the combination of pre-existing materials or concepts to create synthesized content or ideas.

Spatial Data Infrastructure (SDI) refers to the framework of users, data, and tools that allow for the manipulation of spatial or mapping data.

Spatially-enabled web technology may also be considered web maps.

Thematic data describes features of a particular  geographic area.

Ushahidi is an open source project which allows users to crowdsource crisis information sent via mobile phones.

Web 1.0, refers to sites used to simply display information or for commercial purposes.

Web 2.0 commonly refers to applications or websites that facilitate interactive information sharing and user-generated content.

More Info / References

Goodchild, MF (2007) Citizens as sensors: the world of volunteered geography. GeoJournal, 69:4, pp. 211-221

Graham, M. (2010) Neogeography and the palimpsets of place: Web 2.0 and the construction of a virtual earth. Tijdschrift voor economische en sociale geografie, 101: 422–436. doi: 10.1111/j.1467-9663.2009.00563.x

Jones, M.T., 2007. Google’s geospatial organizing principle. IEEE Computer Graphics and Applications, July/August 2007, 8-13.

Haklay, M., Singleton, A. and Parker, C. (2008) Web Mapping 2.0: The Neogeography of the GeoWeb. Geography Compass 2/6 (2008): 2011–2039, 10.1111/j.1749-8198.2008.00167.x Journal Compilation, Blackwell Publishing Ltd

Murugesan, S.; , "Understanding Web 2.0," IT Professional , vol.9, no.4, pp.34-41, July-Aug. 2007 doi: 10.1109/MITP.2007.78

GSDI (2009) SDI cook book.

Turner, A. (2006) Introduction to Neogeography. Published by O'Reilly Media.

Wigand, R. T., Benjamin, R. I., and Birkland, J. L. (2008. Web 2.0 and beyond: implications for electronic commerce. InProceedings of the 10th international Conference on Electronic Commerce (Innsbruck, Austria, August 19 - 22, 2008). ICEC '08, vol. 342. ACM, New York, NY, 1-5.