Quantifying Urban Diversity: Multiple Spatial Measures of Physical, Social, and Economic Characteristics - Computational Approaches for Urban Environments - page 151

In light of the previous research conducted in the area of livability and the
built environment, the research presented here hopes to fill a gap by creating a
methodology that effectively quantifies each of Jacobs' four generators of diversity
in a manner that may be applied to any large city, as well as creating a single
Urban Livability Index which combines all four parameters into a single ranking.
By creating a single index as well as four supporting indices, the methodology
presented may assist city officials in decision-making during the urban planning
process as well as provide a repeatable framework for other researchers in the area
of livability.

7.3 Case Study Data

For this study, the data is from two sources. The first source is the U.S. Census
Bureau, from which the block group geography is obtained. These serve as the
primary units of aggregation and examination for the study. The second source
is the Washington, D.C., city government that provided data for street centerlines
as well as land ownership data that includes a number of important attributes. All
data were projected in the Maryland State Plane Coordinate System (the official
coordinate system for the Washington, D.C., city government), which utilizes a
specific implementation of the Lambert Conformal Conic projection to minimize
the distortion of all measurements within the study area.
The block group file contains 433 block groups and covers the entire city,
including areas owned and operated by the federal government, such as the National
Mall. The street centerline file includes 34,138 street segments (including freeways,
alleyways, driveways, and access ramps) across the entire city, again, including
areas under federal jurisdiction, such as Rock Creek Parkway. The ownership file is
a point file that contains a single point for each ownership record within Washington,
D.C. This file contains a detailed land-use code for each point that corresponds to
a list of 109 possible land-use types designated by the city government. This file
was appended with data for building construction, renovation, and addition dates
for commercial and residential properties, also obtained from the city government.
This information was not available for some buildings, such as educational and
health-care facilities. The greatest challenge with the ownership data is the different
treatment that condominiums and rental units receive. While condominiums in the
same building are each represented as a unique point, an apartment building for
which a single owner rents all the units only contains one point in this file. This
represented a potential difficulty for calculating dwelling densities. However, the
same file that contained information on building date also contained information on
the number of units in each structure. Thus, apartments units that are represented
by a single point for multiple dwellings had the information on the number of units
appended to them.