Intro
- Activity space is an important concept in geography that describes the spatial extent, frequent locations, and movements of people’s daily activities
Literature rivew
- activity space
- activity space using cellphone location data
- clustering methods
Study area and data sets
- Shanghai and Shenzhen
- This article uses two actively tracked cellphone data sets collected weekly in Shenzhen (23 March 2012) and Shanghai (3 September 2012)
Method
Individual mobility indicators
- It introduced daily activity range, which is defined as the maximum distance between all pairs of cellphone towers in T, to describe the spatial extent of an individual’s activity space
- They define an activity anchor point as a set of cellphone towers that are geographically concentrated and where an individual spent a certain amount of time
Estimation of individual home location
- they define the home location of an individual as the activity anchor point with a minimum of four hours of stay at the location before 7:00 a.m.
Building association rules
- Association rules have been widely used in business research to uncover items that are frequently purchased together
Analysis results
General statistics
- the majority of people in Shenzhen had only one or two activity anchor points in the study day
- It is still unclear, however, how the three determinants (N, R, and F) are related to each other in an individual’s activity space
Association rules of IMIs
- To generate the association rules, we first partition the three IMIs into intervals
Discussion and conclusion
- they develop several intuitive IMIs using cellphone location data to describe the major determinants of individual activity space
- they analyze how these mobility indicators (e.g., daily activity range, number of activity anchor points, and frequency of movement) can be combined to analyze an individual’s activity space
- First, quite a few people in both cities stay around one particular location for the whole day
- Second, for the majority of people in Shenzhen, a small activity space was usually enough to fulfill the needs of people’s daily activities
- Third, the geographic disparity of people’s travel range in Shenzhen is significant
