ABSTRACT
Issue What tools are available to examine the spatial and temporal nature of hazards and their impacts?
Introduction Dr. John Snow unraveled the causes of cholera in the mid-ninth century in London by recording on a map the incidence of cholera. He was able to observe from his map the relationship between a public water pump in the center of the cholera outbreak. Although his use of maps to track the cholera outbreak did not prove the cause, it raised a question as to the relationship between drinking water and the public health outbreak. Stronger evidence was obtained to confirm his contention when the water supply was cut off and the outbreak subsided (Gilbert 1958).
