An Interactive Mapping Tool to Assess Individual Mobility Patterns in Neighborhood Studies

Abstract

As their most critical limitation, neighborhood and health studies published to date have not taken into account nonresidential activity places where individuals travel in their daily lives. However, identifying low-mobility populations residing in low-resource environments, assessing cumulative environmental exposures over multiple activity places, and identifying specific activity locations for targeting interventions are important for health promotion. Daily mobility has not been given due consideration in part because of a lack of tools to collect locational information on activity spaces. Thus, the first aim of the current article is to describe VERITAS (Visualization and Evaluation of Route Itineraries, Travel Destinations, and Activity Spaces), an interactive web mapping application that can geolocate individuals' activity places, routes between locations, and relevant areas such as experienced or perceived neighborhoods.

The second aim is to formalize the theoretic grounds of a contextual expology as a subdiscipline to better assess the spatiotemporal configuration of environmental exposures. Based on activity place data, various indicators of individual patterns of movement in space (spatial behavior) are described. Successive steps are outlined for elaborating variables of multiplace environmental exposure (collection of raw locational information, selection/exclusion of locational data, defining an exposure area for measurement, and calculation). Travel and activity place network areas are discussed as a relevant construct for environmental exposure assessment. Finally, a note of caution is provided that these measures require careful handling to avoid increasing the magnitude of confounding (selective daily mobility bias).

Introduction

Neighborhood and health studies have focused on the environmental correlates of diseases.1, 2, 3 However, despite refinements to assess residential environments (e.g., in circular or street network areas centered on the residence; with geographic databases, audits, or survey of residents),4, 5 studies have not taken into account, with few exceptions,6, 7, 8, 9 individuals' nonresidential activity places.1, 4, 10, 11, 12, 13, 14, 15 The result has been a mischaracterization of environmental exposures.¹⁶

A recent review¹ of studies on cardiometabolic outcomes indicated that as much as 90% of the 131 reviewed studies accounted only for the residential environment; 6% took into account only nonresidential exposures (e.g., workplace or school); and only 4% accounted for both residence and another “anchor” point. This failure to take into account an individual's intimate connection with multiple geographic places (or spatial polygamy)15, 17 is one of the main limitations of neighborhood and health studies.13, 18 Accounting for daily mobility patterns and activity spaces is important for health promotion, as it allows identification of low-mobility populations with access to only low-resource/high-exposure residential environments and mobile populations traveling across exclusively low-resource environments; accurate assessment of environmental exposures in multiple activity places; and determination of appropriate activity places (e.g., residence or workplace) for targeting specific interventions.

To aid in developing a new generation of neighborhood and health studies that fully account for individual mobility patterns, the present article first describes the VERITAS application (Visualization and Evaluation of Route Itineraries, Travel Destinations, and Activity Spaces), a tool for researchers to geolocate individuals' activity places, routes between locations, and area delimitations of interest. Second, the paper attempts to formalize the theoretic grounds of a contextual expology (Table 1) and discusses methodologic challenges related to the assessment of “spatial behavior” (individual patterns of movement in space) and multiplace environmental exposures.