The Impact of Census Block Conflation on Census 2000 Related Projects in Delaware County, Ohio

Author: Shoreh Elhami
Organization: Delaware County Auditor

94 N. Sandusky Street
Suite 3A
Delaware, OH 43015
USA

Phone: 740-833-2010
Fax: 740-833-2069
selhami@co.delaware.oh.us

In 1997, Delaware County started a partnership with the Bureau of Census by participating in the Local Update of Census Addresses (LUCA) Program. After reviewing the bureau's master address file (MAF) in 1998, the County's GIS office submitted over 11,000 missing addresses to the MAF. A comprehensive database including road centerlines populated with address ranges, multiple address files were utilized in this process. Another coverage used in this process was the conflated version of the 1990 TIGER block coverage.

The presenters will discuss the process that resulted in identifying the missing addresses, geocoding various address files, and the use of Avenue and a C++ program written for conflating the 1990 block coverage. We will focus on the conflation process from the automated portion of the program (including selecting matching points, rubber sheeting and transformation, and triangulation) to the final manual editing.

The County is currently using this conflated coverage not only for Census 2000 related projects, but also for a variety of other applications such as creation of a voting precinct coverage and conducting demographic analysis at the parcel level.