Geographic Information Systems

The Dangers of Data without Details

To me as a chemistry major, buffers are an additive to a solution that are resistant to pH changes, helping to keep solutions within desired ranges to prevent side reactions or allow analysis with certain methods. But in GIS, a buffer is essentially a range around a point, line, or shape of a predetermined distance. Using buffers is helpful in analyzing data, but only when it’s interpreted correctly.

For this assignment, I decided to compare the overlap between areas within 5 miles of environmental contaminant sites of concern and elementary school districts as recent studies have found that pollution has “long-term consequences on child development outcomes such as academic achievement, having behavioral incidents in school, repeating a grade, and even having a cognitive disability” (read more here). What I found using the ArcGIS buffer tools is that, while “only” 34.11% of the buffer areas of contamination sites are within elementary school districts, 67.31% of the school districts fall within the five mile range of contamination sites.

The same data tells two different stories.

Though the map above looks a bit crowded, it’s easy to see that both those data values are represented by the region with bold, dashed red lines. The difference, then, is the way in which the data was interpreted. Actions taken to remediate the issues should use data analysis like this to mitigate the impact on students in the affected communities. If only one value is used, there is a chance that insufficient actions will be taken.

I think I’ll always remember the ease with which I changed these values and how others could do the same to fit their narratives.

This post meets the requirements of assignment 13 from Spring ’21 ESS302 at Drew University.

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