Table 9 Summary of new and standard buffers
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 |