A theoretical framework and methodology for urban activity spatial structure in e-society: Empirical evidence for Nanjing City, China

The existing researches on the influence of information and communication technology (ICT) are mainly focused on human activity, whilst with few efforts on urban space. In the e-society, the widespread adoption of ICT devices not only affects almost every aspect of people's daily life and thereby reshapes the spatial development of regions and cities, but also generates a large amount of real-time activity data with location information. These georeferenced data, however, have relatively recently attracted attention from geographers. Adapted from Lynch's framework based on people's perceptions, this paper proposes a framework of urban spatial structure based on people's actual activity, including five elements, namely activity path, activity node, central activity zone (CAZ), activity district, and activity edge. In the empirical study, by using one week's check-in tweets (from February 25 to March 3 in 2013) collected in Nanjing City, the five elements are recognized and analyzed. Through the comparison between our results and urban spatial structure based on population (and land use), we argue that ICT uses: 1) lead to polarize, rather than to smooth, the urban structural hierarchy, due to the dual role of distance; 2) enable a partial decoupling of activity and activity space node, which challenges our conventional understanding of the role of home and the utility of travel; 3) blur the boundaries of activity districts and hence may play a positive role in enriching districts' functions, which should not be overlooked in the current urban transformation in China.