By Dax Kelso
Epidemiologists have long used geographic information systems to map data. Recently, some have recognized the advantages of Google Earth for visualizing graphical data and sharing their research. The same qualities that are driving epidemiologists to try Google Earth to map data also make it a promising tool for teaching epidemiology. Specifically, teachers can help students visualize epidemiological concepts by presenting any of the interactive datasets produced by outside sources, or they can actually create their own layers fairly easily. Duke lacks a public health department outside of the medical school, but the following methods of Google Earth implementation in the classroom are certainly adaptable for classes in infectious and emerging diseases, human ecology, and medical sociology.
The easiest way to bring Google Earth into the classroom is with any of the Google Earth “layers” created for academic purposes. The files are in the KML or KMZ format and require little more than downloading them from the Internet. The following are just some of the ways in which these layers can display information:
- Placemarks which link to text or photographs
- Colored overlays (see picture below)
- Photographic overlays
- Animated tours
These layers aid the learning process because they are interactive. Teachers can change the scale of the representation with just a click, zooming from space to street level instantly. They can have multiple layers available at a time and simply turn them “on” or “off.” Then, after teachers present maps in lecture, they can easily email them to their students as attachments for them to examine on their own.
Arguably the most significant epidemiological layer for Google Earth is the Malaria Atlas Project (pictured above; KMZ file), the first major study of malaria endemicity in forty years. Teachers could present the layer in lecture for an interactive visualization of tropical malaria distribution. Alternatively, the layer could be used in a laboratory section to make students think critically about the causes and implications of malaria. For example, students can use Google Earth to identify geographic features (e.g., wetlands) that could potentially harbor mosquitoes, or they could compare the layer with economic data to estimate relative anti-malaria funding between countries.
Google Earth has also been widely used to model the spread of H5N1 avian flu in the mid-2000s. Declan Butler’s layer (available here through Nature magazine, pictured above) is the most detailed. This layer:
- Organizes outbreaks over time.
- Gives data on numbers of affected chickens
- Includes human cases and their outcomes (i.e., recovery or death)
How can I make my own layers?
If you have specialized data that you want to share with students, you can easily create a custom layer of placemarks for Google Earth with the Spreadsheet Mapper tool. The video below gives an overview of how to complete this process, but definitely refer to the link above for more details:
[kml_flashembed movie="http://www.youtube.com/v/6BlecrkM7w4" width="425" height="350" wmode="transparent" /]
Lozano-Fuentes et al. (2008) and Kamadjeu (2009) demonstrated how Google Earth can be applied in the field. With the Spreadsheet Mapper and Google Earth’s own polygon drawing tools, students themselves are also completely capable of transcribing medical data into Google Earth, so teachers could assign projects that utilize Google Earth to display data. In this way, teachers can give students practical experience with epidemiological tools and hopefully pique the interest of the next great epidemiologist.
Kamadjeu, R. (2009). Tracking the polio virus down the Congo River: a case study on the use of Google Earth in public health planning and mapping. International Journal of Health Geographics, 8(4). doi:10.1186/1476-072X-8-4
Lozano-Fuentes, S., Elizondo-Quiroga, D., Farfan-Ale, J. A., Lorono-Pino, M.A., Garcia-Rejon, J., Gomes-Carro, S., … Eisen, L. (2008). Use of Google Earth to strengthen public health capacity and facilitate management of vector-borne diseases in resource-poor environments. Bulletin of the World Health Organization, 86(9), 718-725.