Focus Baumann: Marshall McLuhan’s view of the Global Village is often used to describe the World Wide Web. What is required to nurture a problem-solving geospatial initiative on the Web that would take a leading role in our virtual world community? Goodchild: Geospatial data and tools are essential in almost everything we do as humans, and over the past few years, they have become accessible to virtually all of us on the wellendowed side of the digital divide. We have seen volunteer initiatives, such as MapAction and the GISCorps, playing an important role in disaster response and other volunteer activities that are providing open sources of basic map information in communities that have never previously had access. I think the most significant new opportunity lies in the fact that a substantial fraction of the human population now has access to mobile phones and, hence, to electronic networks. I think mobile phones could be used to acquire and share damage assessments in the immediate aftermath of a disaster and to develop detailed databases for community planning. Project GLOBE has already shown the potential for empowering schoolchildren worldwide as environmental sensors; a new initiative, sponsored by a major foundation, could explore the potential of a much more powerful and comprehensive approach that would reach beyond the digital divide. Baumann: “The bad invariably pushes out the good” is an axiom that has been applied to various disciplines. How true do you think that is when it comes to data quality in VGIbased initiatives? What will happen if individuals or groups subvert, either consciously or simply through a lack of attention, VGI-based projects? For example, you have mentioned a nonexistent café that was geographically referenced to the park in front of the Santa Barbara mission. Goodchild: The experience of Wikimapia seems to be that accurate, large-scale information resources can be created from volunteer action. Wikimapia’s accuracy varies and is most problematic for the more obscure entries that are not accessed very often. Similarly, I think VGI will be most accurate when it concerns the largest, most prominent, and most important features on the earth’s surface. The message in my example of the nonexistent café is that such errors are particularly obvious when the information is geographic, because they conflict with the feature’s spatial www.esri.com context. Wikimapia relies on volunteers with specialist knowledge to monitor information; a similar approach to geographic information that relied on local specialists could work very well to clean out errors. Baumann: You indicate that “computerization carries authority per se.” This perceived authority has been ascribed to other forms of mass media including print and broadcast journalism. The Fourth Estate refers to the press and its ability to both function in the role of advocate and shape public opinion. Do you think VGI and other public mapping efforts play a similar role? When considering the pitfalls of these efforts, Google’s controversial replacement of post-Katrina images of New Orleans with pre-Katrina views springs to mind. Goodchild: Yes, I think there is a tendency to believe what one discovers on the Web, whether the source is authority or assertion. Bad information can always be dressed up to look good. We usually think of metadata as the mechanism for resolving such problems, but asserted sources rarely carry any metadata. Somehow, we need to convince sources such as Google that providing simple metadata, such as the date of acquisition of imagery, would be in everyone’s interests. For more information on this topic, see Goodchild’s 2007 paper on VGI, “Citizens as Sensors: The World of Volunteered Geography,” which is available online at www. ncgia.ucsb.edu/projects/vgi/docs/position/ Goodchild_VGI2007.pdf. ArcUser Spring 2010 21