Combining GPS, GIS, and accelerometry: methodological issues in the assessment of location and intensity of travel behaviors.
BACKGROUND
Global positioning systems (GPS), geographic information systems (GIS), and accelerometers are powerful tools to explain activity within a built environment, yet little integration of these tools has taken place. This study aimed to assess the feasibility of combining GPS, GIS, and accelerometry to understand transport-related physical activity (TPA) in adults.


METHODS
Forty adults wore an accelerometer and portable GPS unit over 7 consecutive days and completed a demographics questionnaire and 7-day travel log. Accelerometer and GPS data were extracted for commutes to/from workplace and integrated into a GIS database. GIS maps were generated to visually explore physical activity intensity, GPS speeds and routes traveled.


RESULTS
GPS, accelerometer, and survey data were collected for 37 participants. Loss of GPS data was substantial due to a range of methodological issues, such as low battery life, signal drop out, and participant noncompliance. Nonetheless, greater travel distances and significantly higher speeds were observed for motorized trips when compared with TPA.


CONCLUSIONS
Pragmatic issues of using GPS monitoring to understand TPA behaviors and methodological recommendations for future research were identified. Although methodologically challenging, the combination of GPS monitoring, accelerometry and GIS technologies holds promise for understanding TPA within the built environment.
Oliver
Melody
M
Centre for Physical Activity and Nutrition Research, Auckland University of Technology, Auckland, New Zealand.
Badland
Hannah
H
Mavoa
Suzanne
S
Duncan
Mitch J
MJ
Duncan
Scott
S
D000054:Acceleration; D000328:Adult; D000704:Analysis of Variance; D004779:Environment Design; D005240:Feasibility Studies; D005260:Female; D040362:Geographic Information Systems; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009520:New Zealand; D012111:Residence Characteristics; D017215:Satellite Communications; D011795:Surveys and Questionnaires; D016138:Walking / Q000706:statistics & numerical data*; D055815:Young Adult