Preserved Digital Content: Value to Public Policy Decision Making Now and in the Future

NC Geospatial Data Archiving Project (NCGDAP)

North Carolina State University LibrariesNorth Carolina Center for Geographic Information & Analysis

Presented by: Steve MorrisHead of Digital Library InitiativesNCSU Libraries

NSDAB Meeting July 24, 2007

• 96 of 100 North Carolina Counties have GIS systems as do many municipalities

• Over 30 state agency data producers

Collection Focus:State and Local Government Geospatial Data

• 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

3 OGC WMS services (web services)

10 web mapping applications

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

NCGDAP Data Types – Raster to Vector

1.) GIS-ready Image Data

County Orthorectified Aerial Photography

3.) GIS Layers

Impervious Surfaces, LandcoverTree Type, Urban Green Space, etc

2.) Feature Extraction

Semi-automated Feature Extraction:Uses Spatial Context, Image Texture,

Multiple layers of data, Existing GIS layers

NCGDAP Data Types – Vector GIS

• Cadastral (tax parcels) • Street centerlines• Zoning• Topographic contours• School, sheriff, fire• Voting precincts• More …

• Detailed, accurate, current

• Frequently updated

NCGDAP Data Types – Other (now and future)

Remote sensing:e.g. LIDAR data

Digital cartographic products: files

Digital cartographic products: web services

Place-based data

Value in Older Data: Solving Business Problems

Suburban Development 1993/2002Near Mecklenburg-Cabarrus County border

Land use change analysis

Real estate trends analysis

Site location analysis

Disaster response

Resolution of legal challenges Impervious surface maps

Problem: Flood and Hurricane Preparedness

Application: Impervious Surface Change Mapping

A. B.

C. D.2002 Impervious 2004 Aerial Photography

2004 Impervious using 2002 Mask 2004 Impervious Update

Problem: Beach Erosion and Shoreline Change

Application: Shoreline Change Mapping

Problem: Tracking Land Use Change

Application: Land Use Change Mapping

Input Data Output GIS Data

Using Mecklenburg County 2002 true color orthorectified aerial photography

Developing Areas

NC Geospatial Data Archiving Project (NCGDAP)

Partnering with Spatial Data Infrastructure (SDI) to temporally enable geospatial work

http://www.lib.ncsu.edu/ncgdap

http://www.nconemap.net