Proximity analysis measures nearness between features—distances, nearest neighbors, buffers—and interprets implications for access, risk, or interaction. It can be Euclidean (straight-line) or network-based along routes. Analyses include drive-time polygons, nearest facility, spatial joins within thresholds, and kernel densities. Scale and units matter: feet for building codes, minutes for service access. Proximity can imply interaction (e.g., pollution exposure) but is not causation; context like wind or flow direction may dominate. Good practice states assumptions and uses appropriate coordinate systems so results are meaningful and reproducible.