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Table 9 Summary of new and standard buffers

From: Using GPS technology to (re)-examine operational definitions of ‘neighbourhood’ in place-based health research

Buffer Short description Based on Pros Cons
Circular Area ‘as the crow flies’ delineated as a predefined distance from a reference point Radius from central location Easy to create May incorporate areas not used for physical activity
Polygon Network Area within a polygon up to a certain distance from a central location when travelling along a network Road network More accurately represents area activity can take place May incorporate areas not used for physical activity
Line-based network Land of a predefined distance either side of a road up to a certain distance from a central location when travelling along a network Road network Only represents land along a network May under represent areas used for physical activity
Variable width Land as defined by circular and/or network buffer limited by cost of travel from a central location Cost of movement across a grid cell Takes actual walking behaviour into account Requires information on walking behaviour
RIC polygon Area identified as the smallest convex hull around all recreational, institutional, commercial (RIC) facilities and a central location Facility locations Captures neighbourhood orientation, only land between a central location and up to possible destinations is included, fast polygon generation Inaccessible land included
RIC ellipse All land within an ellipse created around recreational, institutional, and commercial (RIC) facilities within a predefined distance from a reference point Facility locations Captures neighbourhood orientation, shows directional information Possibly excludes the home from the buffer, inaccessible land included
RIC line Land of a predefined distance either side of a road from a central location to recreational, institutional, and commercial (RIC) facilities along a network Road network, facility locations Captures neighbourhood orientation, includes only land between a central location and facilities people are expose to Requires information on walking behaviour and only incorporates shortest routes to facilities