  The growth of cities calls for regulations on how urban space is used and
zoning resolutions define how and for what purpose each piece of land is going
to be used. Tracking land use and zoning evolution can reveal a wealth of
information about urban development. For that matter, cities have been
releasing data sets describing the historical evolution of both the shape and
the attributes of land units. The complex nature of zoning code and land-use
data, however, makes the analysis of such data quite challenging and often
time-consuming. We address these challenges by introducing Urban Chronicles, an
open-source web-based visual analytics system that enables interactive
exploration of changes in land use patterns. Using New York City's Primary Land
Use Tax Lot Output (PLUTO) as an example, we show the capabilities of the
system by exploring the data over several years at different scales. Urban
Chronicles supports on-the-fly aggregation and filtering operations by using a
tree-based data structure that leverages the hierarchical nature of the data
set to index the shape and attributes of geographical regions that change over
time. We demonstrate the utility of our system through a set of case studies
that analyze the impact of Hurricane Sandy on land use attributes, as well as
the effects of proposed rezoning plans in Downtown Brooklyn.
