## 1 Introduction  
The positive effects of physical activity (PA) on physical and mental health [1; 2], health-related quality of life [3], and healthy ageing [4] have been extensively documented. However, worldwide, the percentage of adults who do not meet World Health Organization recommendations for PA is still 31.1% [5]. Insufficient PA is seen as a major public health problem, which puts a high demand on society due to the high costs it generates [1; 6]. The built environment (_i.e._, the spatial organization of residential, work, shopping- and recreational areas, their layout and appearance, and the transportation system connecting them) has been identified as a factor that influences PA levels [7; 8]. For example, neighborhood walkability and street connectivity have been found to be associated with active transport, and factors such as safe crossings, pavement, greenness, attractiveness, and proximity to facilities for recreation have been identified as correlates of leisure activity [8]. Most research into the relationship between the built environment and health behaviors such as PA has focused on the residential environment [9] and its effect on total PA or on a specific type of PA, such as walking or cycling [7; 10; 11]. However, as [PERSON] _et al._ (2006) stated in their ecological model of active living [12], individuals interact with various environments as they participate in different types of activities at different places throughout the day (active transport, occupational activities, household activities and active recreation). This suggests that researchers should study PA behavior in a broader geographical context than the neighborhood alone. Since specific physical activities are often related to certain elements of the built environment such as parks, infrastructure, and building complexes (e.g., infrastructure can influence transport-related PA), understanding the effects of the built environment on PA ideally requires that levels of PA are assessed for specific locations. The increasing awareness that the impact of the built environment on PA should be understood and measured for specific locations has recently spawned a stream of studies that used accelerometers and GPS-devices to assess location specific PA. Most of these studies have investigated children's PA behavior. These studies distinguished indoor and outdoor PA behavior, PA within and outside children's neighborhoods, and (MV)PA at various locations such as the home, gardens, green spaces, schoolyards, playgrounds, sports facilities and streets (see e.g., [13; 14; 15; 16; 17; 18; 19]). In addition, [PERSON] _et al._ (2013) investigated the locations (e.g., residential locations, public facilities and open spaces) of joint MVPA of children and their parents [20]. As for adults, less evidence is available about the types of built environments where they actually spend their time, and what levels of PA they engage in at different locations [21; 22]. [PERSON] _et al._ (2005) described adults' PA levels indoors and outdoors within and outside the neighborhood [23]. Other studies assessed at what distance from home adults were physically active [24; 25], or described the size and characteristics (fast food outlet density, number of supermarkets, and park land use) of activity spaces (_i.e.,_ the subset of all locations with which individuals interact during their daily activities) in relation to PA behavior [26; 27]. However, these studies used a relatively rough classification when determining the geographical locations where adults were physically active. [PERSON] _et al._ (2014) studied a more extensive set of specific locations that were used for PA: they assessed the frequency of use of the home/backyard, neighborhood sidewalks, neighborhood parks, workplace, state parks and gyms [28], but they used self-report measures (surveys). Moreover, most studies of the effect of the environment on PA describe the distribution of PA across location types for the population as a whole, or for a limited number of subgroups.