Traditionally urban structure and development are monitored using infrequent
high-quality datasets such as censuses. However, human culture is accelerating
and aggregating, leading to ever-larger cities and an increased pace of urban
development. Our modern interconnected world also provides us with new data
sources that can be leveraged in the study of cities. However, these often
noisy and unstructured sources of big data pose new challenges. Here we propose
a method to extract meaningful explanatory variables and classifications from
such data. Using movement data from Beijing, which is produced as a byproduct
of mobile communication, we show that meaningful features can be extracted,
revealing for example the emergence and absorption of subcenters. In the future
this method will allow the analysis of urban dynamics at a high spatial
resolution (here, 500m) and near real-time frequency