The Effects of GPS-Based Buffer Size on the Association between Travel Modes and Environmental Contexts
1
Illinois Informatics Institute, University of Illinois at Urbana-Champaign, 616 E Green Street Suite 210, Champaign, IL 61820, USA
2
Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, Hong Kong, China
3
Institute of Space and Earth Information Science, The Chinese University of Hong Kong, Shatin, Hong Kong, China
4
Department of Human Geography and Spatial Planning, Utrecht University, 3584 CB Utrecht, The Netherlands
*
Author to whom correspondence should be addressed.
ISPRS Int. J. Geo-Inf. 2019, 8(11), 514; https://doi.org/10.3390/ijgi8110514
Received: 15 October 2019 / Revised: 8 November 2019 / Accepted: 11 November 2019 / Published: 13 November 2019
(This article belongs to the Special Issue Geospatial Methods in Social and Behavioral Sciences)
To investigate the association between physical activity (including active travel modes) and environmental factors, much research has estimated contextual influences based on zones or areas delineated with buffer analysis. However, few studies to date have examined the effects of different buffer sizes on estimates of individuals’ dynamic exposures along their daily trips recorded as GPS trajectories. Thus, using a 7-day GPS dataset collected in the Chicago Regional Household Travel Inventory (CRHTI) Survey, this study addresses the methodological issue of how the associations between environmental contexts and active travel modes (ATMs) as a subset of physical activity vary with GPS-based buffer size. The results indicate that buffer size influences such associations and the significance levels of the seven environmental factors selected as predictors. Further, the findings on the effects of buffer size on such associations and the significance levels are clearly different between the ATMs of walking and biking. Such evidence of the existence of buffer-size effects for multiple environmental factors not only confirms the importance of the uncertain geographic context problem (UGCoP) but provides a resounding cautionary note to all future research on human mobility involving individuals’ GPS trajectories, including studies on physical activity and travel behaviors, especially on the reliable estimation of individual exposures to environmental factors and their health outcomes.
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MDPI and ACS Style
Lee, K.; Kwan, M.-P. The Effects of GPS-Based Buffer Size on the Association between Travel Modes and Environmental Contexts. ISPRS Int. J. Geo-Inf. 2019, 8, 514. https://doi.org/10.3390/ijgi8110514
AMA Style
Lee K, Kwan M-P. The Effects of GPS-Based Buffer Size on the Association between Travel Modes and Environmental Contexts. ISPRS International Journal of Geo-Information. 2019; 8(11):514. https://doi.org/10.3390/ijgi8110514
Chicago/Turabian StyleLee, Kangjae; Kwan, Mei-Po. 2019. "The Effects of GPS-Based Buffer Size on the Association between Travel Modes and Environmental Contexts" ISPRS Int. J. Geo-Inf. 8, no. 11: 514. https://doi.org/10.3390/ijgi8110514
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