TIGER/Line files 1992, although a significant improvement over TIGER 1990, is still fraught with inaccuracies and inadequacies. Due to the increasing awareness and improvements in GIS technology, many m______ p_____ o______s (MPOs) have developed their own versions of street centerline files. These, however, are partially complete or partially accurate either in their coverage or in their attributes. This poses a significant problem of integration and redundancy and raises questions about duplication of where to invest scarce resources. Maricopa County, Arizona, is the third largest in terms of TIGER/Line file size. Maricopa Association of Governments (MAG), with the help of GIS consultant GIS Southwest, solved the problem by developing ArcInfo-based programs to integrate five different coverages, each with varying levels of accuracy for either shapes or address ranges or attributes. These programs are AML-based and significantly advance the capabilities of ArcInfo Version 7.0 in the area of conflation. The process was designed to be automated, repeatable, and computer-process oriented instead of employing manual labor. Since the process is designed in ARC Macro Language (AML) instead of C language, its conceptual framework is transferable.
Small and large MPOs using WorkStation ArcInfo Version 7.0 or later can now integrate several street centerline files having only one shared attribute a street name and suffix. This is accomplished with a combined process of logical relates and spatial relates which ensure massive one-to-one relates and then transferring either arcs or attributes via unique IDs for each feature. The resulting file has "cascading" accuracy. The most accurate features and attributes are transferred first, then second most accurate, and so on. This way the process ensures incluson of every possible feature with all accuracies in the final file. This can then be submitted to the Census Bureau as the local TIGER/Line file in 1992 TIGER format.
B.J. Raval
GIS Southwest, Inc.
4621 N. 16th St., Suite B213
Phoenix, AZ 85016-5130
Telephone: 602-266-5080
Fax: 602-266-5256
Stephen M. Boege