This paper will describe what geographic information systems (GIS) are and provide an overview of the benefits of their deployment in a public health setting. It will then describe the major methodological challenges that must be addressed when implementing a spatial analysis project in a public health setting. A six step conceptual framework for thinking about how to proceed with the spatial analysis of public health surveillance data will be outlined. These steps will highlight why practitioners should conceptualize their project to meet their business needs and be realistic about the resource implications of their project. These will also help practitioners realize the benefits and importance of moving beyond simple visualization of spatial trends to a more robust understanding of the ecology of a health issue and the implications this may have for the design, implementation and evaluation of public health programs. Finally, the paper will highlight the activities of several public health departments which have successfully integrated GIS into their routine activities. It is the intention of this paper to provide readers not only with a sense of the exciting possibilities and potential that GIS holds for improving public health practice, but also provide clear insight into the challenges and resource implications of implementing this technology in a public health setting.
Note: The PDF was originally in colour but, due to its size, is now black and white.
Key Points:
The application of geographic information systems (GIS) to public health practice has great potential for improving our understanding of the ecology and causes of complex health issues, and for guiding the design and evaluation of effective population based programs and strategies.
GIS can summarize vast amounts of tabular data into compelling visual maps that can provide powerful insights and engage the attention of policy makers and the public.
There are significant methodological issues which must be addressed in order to ensure that map outputs are interpretable and not misleading. The most important of these is dealing with the small number problem which occurs when cases and their associated denominators are sub-divided into many small geographic areas which frequently result is in significant rate instability.
Although the creation of maps is an important step in public health mapping, it is critical for practitioners to move beyond simple data visualization to an exploration of the statistical characteristics of spatial patterns and to formalized modeling of the relationship between predictor and outcome variables.
The implementation of GIS in a public health context can be a resource intensive activity, requiring a significant investment.
