A case study of social vulnerability mapping: issues of scale and aggregation

Abstract

This study uses geographic information systems to determine if the aggregation of census block data are better than census block group data for analyzing social vulnerability. This was done by applying a social vulnerability method that used census block group data for a countywide analysis and converting it to use census blocks for a countywide analysis and a municipal-wide analysis to determine which level of aggregation provided a more precise representation of social vulnerability. In addition to calculating the social vulnerability, the results were overlaid with an evacuation zone for the threat of a train derailment, determining which aggregation better depicted at-risk populations. The results of the study showed that the census blocks enable a more exact measurement of social vulnerability because they are better at capturing small pockets of high-risk areas. This study concludes that census block are more advantageous than census block groups because they are more sensitive and geographically exact in measuring social vulnerability, allow for a better interpretation of social vulnerability for smaller areas, and show spatial patterns of vulnerability at a finer spatial scale.