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Preserved Digital Content: Value to Public Policy Decision Making Now and in the FutureNC Geospatial Data Archiving Project (NCGDAP)North Carolina State University LibrariesNorth Carolina Center for Geographic Information & AnalysisPresented by: Steve MorrisHead of Digital Library Initiatives NCSU Libraries NSDAB Meeting July 24, 2007
Collection Focus: State and Local Government Geospatial Data • 96 of 100 North Carolina Counties have GIS systems as do many municipalities • Over 30 state agency data producers • Exceptional value • Detailed, current, accurate • Exceptional risk • Inconsistent or nonexistent archiving practices • Complicated formats and complex objects Source: NC OneMap
Carrboro, NC : Population 17,797 (2005 est.) 22 downloadable GIS data layers 10 web mapping applications 3 OGC WMS services (web services) 9 downloadable PDF map layers
NCGDAP Data Types – Digital Orthophotography • All 100 NC counties with orthos • 1-5 flight years per county • 30-300 gb per flight
2.) Feature Extraction 1.) GIS-ready Image Data 3.) GIS Layers Semi-automated Feature Extraction: Uses Spatial Context, Image Texture, Multiple layers of data, Existing GIS layers CountyOrthorectified Aerial Photography Impervious Surfaces, Landcover Tree Type, Urban Green Space, etc NCGDAP Data Types – Raster to Vector
NCGDAP Data Types – Vector GIS • Detailed, accurate, current • Frequently updated • Cadastral (tax parcels) • Street centerlines • Zoning • Topographic contours • School, sheriff, fire • Voting precincts • More …
NCGDAP Data Types – Other (now and future) Digital cartographic products: web services Digital cartographic products: files Remote sensing: e.g. LIDAR data Place-based data
Value in Older Data: Solving Business Problems Land use change analysis Site location analysis Real estate trends analysis Disaster response Resolution of legal challenges Impervious surface maps Suburban Development 1993/2002 Near Mecklenburg-Cabarrus County border
Application: Impervious Surface Change Mapping A. B. 2004 Aerial Photography 2002 Impervious D. C. 2004 Impervious Update 2004 Impervious using 2002 Mask
Developing Areas Application: Land Use Change Mapping Output GIS Data Input Data Using Mecklenburg County 2002 true color orthorectified aerial photography
NC Geospatial Data Archiving Project (NCGDAP)Partnering with Spatial Data Infrastructure (SDI) to temporally enable geospatial workhttp://www.lib.ncsu.edu/ncgdaphttp://www.nconemap.net