Updating Census Tiger GeographyCreating and Maintaining a Current MCD and Municipal Ward Layer Tony J.Van Der Wielen GIS Manager Legislative Technology Services Bureau Sarah Kemp Associate Researcher UW Applied Population Laboratory
The Problem: Census Municipal Boundaries are not Spatially Accurate• After modernization the spatial accuracy of TIGER line files has been updated to +/- 7.6 meter (+/- 25 feet) – In many areas the spatial accuracy of TIGER is better than +/- 5 meters.• Municipal boundaries are still inaccurate. – The Census Bureau relies on all communities to participate in the Boundary Annexation Survey (BAS) on a yearly basis to update municipal boundaries. – Local communities are the only entities that can legally update the municipal boundaries in TIGER (1,900 communities). – BAS is performed every year between January and March.• Why is this a problem? – Local, Legislative and Congressional Redistricting – Elections – These boundaries are used by Federal and State governments/programs
A Possible Solution: County Consolidated BAS• County Consolidated BAS – Allows a County to legally submit all (or most) of the municipal boundaries to the Census Bureau • This can be done electronically with existing GIS files already being maintained at the county • Requires municipalities to “sign off” • Allow the Census Bureau to work with fewer government entities • Census will provided template forms and detailed instructions • August 1st Deadline for 2013 BAS• LTSB Tools and Support – WISE-LR • Data management tool to continually maintain municipal ward datasets • Statewide Municipal Ward and Municipal Boundary generation – LTSB Data Integration Tool – ArcGIS Mxd file • Tool to compare Census BAS GIS files with local datasets • Generates a change file that can be submitted directly to the Census Bureau for spatial correction of municipal boundaries • Municipal annexation processing – Will include annexation in statewide layer and will process for BAS.
Project ResourcesUS Census Bureau – Boundary Annexation Surveyhttp://www.census.gov/geo/www/bas/bashome.htmlGail A. Krmenec – Supervisory Geographer630-288-9258Gail.email@example.comLegislative Technology Services Bureauhttp://legis.wisconsin.gov/LTSB/BASTony J. Van Der Wielen – GIS Manager608-283-1817Tony.firstname.lastname@example.orgApplied Population Laboratoryhttp://www.apl.wisc.edu/Sarah Kemp – Associate Researcher608-265-6189Kemp@wisc.edu