Lower Adirondack GIS Users Group Meeting Warren County Street Centerline Project December 1, 2004

Background Warren County : ~ 1200 miles of public roads ~ 600 miles of private roads County completed in-house : ~ 450 miles geometry ~ 200 miles attribution Error checking of 1 town Summer 2004 – the Sheriff’s Department hired a consultant, (Applied GIS, Inc.) to complete the project

Existing Road Data NYS DOT roads TIGER roads NYS Accident Location Information System (ALIS) These data sources have inaccuracies in geometry and attribution (especially consistency with E-911 address ranges)

Data Sources for Geometry Development 2001 Digital Orthoimagery Tax Parcel layer with RPS Road Centerlines from ALIS GPS field work

GPS used to delineated roads that were not visible on the orthoimagery

Geometry Methodology Divided Roads: Line segments head’s up digitized following the road’s centerline (where visible) Undivided and Dirt Roads: Line segments within the edge of the roadbed

Geometry Methodology Complex Features: –Cul-de-sacs –Multiple lane highways –Divided highways Follow ALIS Project Rules

Attribution Methodology Based on Warren County’s Dispatch System Primarily manual coding, referencing Sheriff Department Excel spreadsheets 14 fields manually entered Additional fields obtained from Sheriff Department Excel

Attribution Methodology Manual Attributes Coded: Street NamePre-Direction Pre-TypeStreet Type Suffix DirectionFrom Left Address Range To Left Address RangeFrom Right Address Range To Right Address RangeLeft ZIP Right ZIPLeft Venue Right VenueAlias Fields

Attribution Methodology Address ranges interpolated from Excel data fields Cross reference with other sources: –Spreadsheets listing residents’ names and house numbers (available for ~ half the towns) –Real Property data (BUT! not consistently accurate for E-911 addresses)

Error Checking Type 1: Compare Sheriff Excel spreadsheet address ranges to other available sources –Error report of unresolved cases provided to Sheriff’s Department –Sheriff’s Department field checked, corrected data sent back to Applied GIS for update

Error Checking Type 2: Geocode in ArcGIS the County’s Voter Registration database for each town. –Errors identified as either: Mistake in address ranges of data (correction by consultant) Error in voter registration database

Problem County’s address ranges were developed independent of GIS, therefore address ranges may not be consistent with road length

Thank You!