  High-speed rail (HSR) has become an important mode of inter-city
transportation between large cities. Inter-city interaction facilitated by HSR
tends to play a more prominent role in promoting urban and regional economic
integration and development. Quantifying the impact of HSR's interaction on
cities and people is therefore crucial for long-term urban and regional
development planning and policy making. We develop an evaluation framework
using toponym information from social media as a proxy to estimate the dynamics
of such interactions. This paper adopts two types of spatial information:
toponyms from social media posts, and the geographical location information
embedded in social media posts. The framework highlights the asymmetric nature
of social interaction among cities, and proposes a series of metrics to
quantify such impact from multiple perspectives, including interaction
strength, spatial decay, and channel effect. The results show that HSRs not
only greatly expand the uneven distribution of inter-city connections, but also
significantly reshape the interactions that occur along HSR routes through the
channel effect.
