Choropleth maps are thematic maps where areas are shaded in proportion to the value of its measurement unit. The animations provided allow one to not only see the static breakdown of cancer mortality across the United States, but also, when viewed together as a video, the gradual spatial diffusion. The application of such technique would be invaluable in times of epidemic spread in order to identify origin and path/rate of diffusion.
Viewing the female and male skin cancer videos reveal a general northward trend in the death rate of white Americans. This would prove crucial to a medical geographer as it proves that proximity to the equator, once thought to be the vital attribute in skin cancer, is now a diminishing factor in the spatial distribution of the disease. Furthermore, the male animation reveals that they are much more likely than females to die of skin cancer. It also further raises questions when one sees the southern border of Texas, one of the most southern places in the US, maintains a low death rate. This anomaly would serve medical geographers and epidemiologists to focus on the environmental and social factors in the region as further investigation may encounter an attribute that is directly responsible for the low rates. While the answer in this study may be found in the majority population of Hispanics, whose darkly pigmented skin decrease their chance of contracting cancer, the ability to spot anomalies quickly through animated visuals would enable health officials to quickly identify regions of interest. In the time of an epidemic, for example, if one region had an abnormally low contraction of the disease, doctors could analyze the local social and environmental situations to identify what attribute is successfully deterring the spread of disease and apply it elsewhere.
In order to provide a more gradual transition, I interpolated 1982 data by halving the difference between 1994 and 1970 values.
The Leukemia animation is quite intriguing as its visualization could be utilized to suggest the success of implemented government policies. While often attributed as a product of radiation exposure, humans can also contract leukemia from frequent contact with bio-hazardous chemicals. Interestingly enough, the 1970 map depicts a high concentration of leukemia mortality in the Midwest where the majority of our farms are located. Dichlorodiphenyltrichloroethane, or DDT, was a heavily utilized agricultural pesticide until scientific publications in the mid sixties connected its use with the spread of cancer and extreme environmental degradation and animal deaths. Therefore it could be inferred that the 1972 Federal ban on DDT was a major player in having the 1990 values of leukemia plummet.
In this light, chorolopleth animation could also be used by conservational biologists in addition to medical purposes as it shows the positive effects of the removal of a toxin from the environment.
The con to this technique is the manipulation and/or misrepresentation of data that can occur via data classing. The class breaks, or color patterns, and color choices are poised to lead a reader into thinking a certain aspect. Here, for example, I mapped high cancer rates with red as red is synonymous with danger or caution. Cartographers, if trying to seek a certain return, could manipulate colors and class breaks so that a problem looks more/less grave than it actually is.