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DMINews -- March 2008
Topics: • TIGER/Line Shapefiles - new this month • Assessing County Population Change - updated/extended estimates • County-to-County Migration Analysis - updates • School District Ranking Tables - updated and extended; new structure • Census 2010 Census Tract and Block Group Criteria TIGER/Line Shapefiles The Census Bureau TIGER/Line files (TLF) have been the backbone for development of vector-based geographic data at the street segment level for the U.S. for more than 20 years. The author of DMINews was developer of the Columbia, MO GBF/DIME file, used for the prototype TLF development. The TLFs have enabled the evolvement of wide-ranging GIS products and Web-based mapping applications. The legacy TLF is now being superseded by the TIGER/Line shapefiles, initially becoming available this month. See the April 2008 DMINews for information on use of the new TIGER/Line shapefiles. Assessing Annual County Population Change -- new official 2007 county estimates Four of the 10 fastest growing counties between 7/1/00 and 7/1/07 are in Georgia. How have your counties/regions of interest changed? The new 2007 (7/1/07) official county population estimates, components of change, and revised previous year estimates (2000 forward) were released by the Census Bureau on 3/20/08. See these related Web pages: • General summary of county population patterns -- http://proximityone.com/cty0007.htm • U.S. by county interactive population ranking table -- http://proximityone.com/cty07rnk.htm Among others, these data are integrated into the following Proximity tools/resources: • MetroDynamics -- http://proximityone.com/md.htm • CountyTrends -- http://proximityone.com/countytrends.htm County-to-County Migration Analysis Annual migration estimates are included with the 2007 County Population Estimates dataset summarized above. But those migration data tell us only how many people moved -- not how many people moved from where or to where. The Proximity county-to-county migration analysis tool provides a way to examine patterns of in- and out-migration for any particular county by origin and destination county based on movers between 1995 and 2000. Annual updates to the Census 2000-based data on movers now included using IRS tax return data. See the MigrationAnalyst Web page for more information. School District Ranking Tables School district demographics interactive ranking tables, accessible via links in the left column of http://proximityone.com/sddmi.htm, have been updated and extended. registered users click on links adjacent to state of interest to view the ranking tables: • T1 link to view/sort/examine Census 2000 demographics • T2 link to view/sort/examine 2000 demographics, 2005 demographics, and change • T3 link to view/sort/examine sources and uses of funds Use Delaware to view ranking table examples: T1 | T2 | T3 See description of items included. Census 2010 Census Tract and Block Group Criteria Census block groups, designed to average 1,000 population for Census 2000 (the average BG population for Georgia's 4,788 BGs was 1,710), are the smallest geographic areas for which the richer decennial census data are tabulated for public use. Census tracts, groups of contiguous block groups and designed to average 4,000 population, are often used to equivalence neighborhoods and various types of market and service areas. They are the smallest geographic areas for which more detailed "PCT" and "HCT" tables were tabulated from Census 2000 (the average tract population for Georgia's 1,618 tracts was 5,060). Census tracts are often used as a "smallest geographic area" for collecting and tabulating non-census data, such as birth and death data. The Census Bureau published final criteria for both census tracts and block groups in the Friday, March 14, 2008 Federal Register: • Census Tract Program for the 2010 Decennial Census--Final Criteria • Census Block Group Program for the 2010 Decennial Census--Final Criteria Both notices are on the Census Bureau Website: Participant Statistical Areas Program. The block group notice announces the Census Bureau's decision that the minimum population threshold for block groups will continue to be 600 persons. Additional Information Contact Proximity for more information about any of the topics reviewed in this section. |
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