For many infectious diseases close personal contact is important in transmission. The geographic distribution of contacts dictates the disease’s spatial rate of spread and which communities are infected. Contact questionnaires are used to determine how and where contacts occur, but
often depend on the ability of interviewees to recall the distance from their home at which contacts are made. Satellite imagery has proven useful to epidemiologists, providing a way to identify households when accurate census information is not available, helping to characterize environmental risk factors, and enhancing the display of epidemiologic data. However, satellite imagery is rarely used in interviews. We present a computer application built on Google Earth that allows the interviewee to identify the location of close personal contacts on a high resolution satellite image of the surrounding area. Using Google Earth allows users to zoom out from the
local area to identify more distant contacts. Many interviewees are unable to identify their location or that of their contacts; but once key landmarks are identified, most interviewees are quickly able to identify the location of contacts. This application is most useful for distant contacts and in rural settings. In urban areas the density and homogeneity of buildings causes problems; however, street map overlays may be useful in orienting users. Regardless of their ability to identify the location of contacts, the ‘‘cool’’ factor of the satellite imagery increased the enthusiasm of participants. Our experience suggests that satellite imagery is a powerful tool, not only for
communication between scientists, but for communication between researchers and study participants.