Buffer type | Shape | Definition |
---|---|---|
Activity space (AS) [Calculated using GPS data] | An area within which individual moves or travels during the course of their daily activities (i.e. everywhere a participant went for 7Â days) | |
Straight-line buffer (SLB) [Calculated using questionnaire data] | An area around a straight-line distance between two points of interest [18] (i.e. a buffer around a Euclidean distance between participant’s home and workplace) | |
Circular buffer around home/workplace (CBH/W) [Calculated using questionnaire data] | A circular area around home (i.e. a circular buffer around a participant’s home/workplace) | |
Circular buffer around both home and workplace (CBHW) [Calculated using questionnaire data] | An area formed by two circular buffers around home and workplace. It can be fused or two distinct circular areas | |
Street network buffer around workplace (SNBH/W) [Calculated using questionnaire data] | An area that could be reached by a participant within a specified travel distance (i.e. 2Â km, 4Â km and 6Â km) from home/workplace along a street network | |
Standard Deviational Ellipse (Lobstein et al.) [Calculated using GPS data] | A measure of the trend of points (i.e. GPS points of participant’s movements) or orientation of an area (i.e. AS) 2 SDE refers to space around 95% of all GPS points of participants movements |