An analysis of alternative classification schemes for medical atlas mapping.

Most national disease atlases adopt a classification scheme based on either the percentile distribution of rates or on the national mean. Although these schemes have a direct interpretation, they are based on the univariate statistical distribution of rates and not on their spatial distribution, and distort the underlying spatial autocorrelation in the data. If the purpose of the maps is to represent spatial patterns, alternative classification schemes might be more appropriate. This research proposes an alternative classification method that maximises spatial similarity among contiguous units in the same class interval. The method has been illustrated using selected data from the German Cancer Atlas published in 1984.

Using a geographic information system to understand child pedestrian injury.

Data from police accident reports involving pedestrians less than 20 years of age in Hartford, Conn, during 1988 through 1990 were abstracted and entered into a geographic information system. Two high-frequency collision areas were identified and compared. There were 374 child pedestrians involved in collisions (a rate of 28 per 10,000). Two high-occurrence areas accounted for 30% of collisions. Collisions in one of these areas were more likely to involve younger children (8.1 vs 10.2 years of age) and to occur in the late afternoon, and occurred closer to the child's residence, than collisions in the other area. The geographic information system is a useful tool in the study of child pedestrian collisions.