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Data sets for the indexes (PII) and codes
(PIZA) are provided in three different formats with slightly
different fields depending on the format: for the years 1980, 1990,
and 2000.
Formats
1. ArcInfo GRIDS—GRIDS for
the PII and PIZA are provided as ESRI export files. Each grid is
accompanied by an associated metadata file. Use of the ESRI
Shapefiles and the Arc/Info GRIDS requires the availability of a
GIS with ArcView/ArcInfo.
2. ESRI Shapefiles—A
shapefile is provided for the PIZA data. The shapefile is provided
as a .ZIP file. The shapefile is accompanied by an associated metadata
file. Use of the ESRI Shapefiles and the Arc/Info GRIDS requires
the availability of a GIS with ArcView/ArcInfo.
3. County-Level PII and PIZA Text
File—A text file contains the county-level indexes
and zones for Population-Interaction:
| Field |
Description |
| FIPS |
A five-digit county indentifier |
| PII1980 |
The population interaction index for
1980 for the entire county |
| PIZA1980 |
The population interaction zones for
1980 for the entire county, rounded to nearest value |
| PII1990 |
The population interaction index for
1990 for the entire county |
| PIZA1990 |
The population interaction zones for
1990 for the entire county, rounded to nearest value |
| PII2000 |
The population interaction index for
2000 for the entire county |
| PIZA2000 |
The population interaction zones for
2000 for the entire county, rounded to nearest value |
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