Hall of Mirrors
Impact of Distance Calculation Methods on Geospatial Analysis of Health Care Access (304951)
*Sarah Camilla Lotspeich, Vanderbilt UniversityRobert E. Johnson, Vanderbilt University
Keywords: Semivariogram, Kriging, Primary Care
The CDC publishes the CHSI dataset, providing county-level key health indicators for the United States. The current analysis focuses on the density of primary care physicians per 100,000 people as a gauge of healthcare access in a subset of 878 counties in Tennessee. Access to primary care may be measured by travel distance or travel time. We investigate the implications of travel time and two distance measures: travel distance and travel time using the Google Maps API and shortest distance ("as the crow flies") using the Haversine formula. These measures were used to create empirically estimated (classical) semivariograms. We utilized ordinary kriging methods (OK) to interpolate the density of primary care physicians in the areas between the geographic centroids of the counties (three analyses total). We will compare kriged results between the three methods, illustrate results with maps, and explore the relationships between travel distance/time and Haversine distance.