National Water-Quality Assessment (NAWQA) Program
U.S. Geological Survey
Water-Resources Investigations Report 94-4250
Refining 1970's Land-Use Data With 1990 Population Data to
Indicate New Residential Development
By Kerie J. Hitt
Abstract
A procedure using a geographic information system was developed to
define urban land use representative of the 1990's by overlaying
U.S. Bureau of the Census 1990 population density at the block group
level on 1970's digital land-use data from 1:250,000- and
1:100,000-scale maps. Any area having a population density of 1,000 or
more people per square mile is re-classified as "urban" land
use in the derivative product. The procedure was applied to 20 study
units of the National Water-Quality Assessment program to provide what
are considered reasonable indications of urbanization that has
occurred since the 1970's.
Table of Contents
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