1 Virginia Geographic Information Network Virginia’s Elevation Framework Layer Upcoming LiDAR...

www.vita.virginia.gov 1

Virginia Geographic Information Network

Virginia’s Elevation Framework Layer Upcoming LiDAR Projects and the

Elevation FIATJohn Scrivani

Geospatial Projects Manager

VGIN Board Meeting April 7, 2010




Topics• Framework Layers & Spatial Data

Infrastructure (SDI)• Elevation Data – NED and Elevation for the

Nation• Virginia LiDAR Projects• Elevation Framework Initiative Action Team

(Elevation FIAT)




Spatial Data InfrastructureFramework Layers (NSDI)1. Geodetic control2. Digital orthoimagery3. Elevation4. Transportation5. Hydrography6. Governmental Units7. Cadastral

Presidential Executive Order 12906April 1994




Why “Infrastructure”?In the information age digital data is a

basis for economic growth, public safety, public health, and environmental protection;

Akin to asphalt roadways, metal pipes and public buildings.



Why “Framework”?• "themes of geospatial data that are used

by most GIS applications“ OMB Circular A-16

Framework layers are:– Needed for many diverse purpose– Needed across all jurisdictions– Needed to be standardized and compatible– Too expensive to be created and used just once– Amenable to economies of scale



Elevation• distance measured upward

along a plumb line between a point and the geoid (mean sea level)

• a data layer representing the surface of the earth in a consistent fashion (datum, units, map projection)

• Sources– Field surveys– Contour maps– Photogrammetric

analysis of aerial photography

– LiDAR

• Uses– Floodplain mapping, stream &

watershed delineation– Engineering & construction– Real estate development– Pipeline and power line

planning– Environmental analysis



National Elevation DatasetNational Elevation Dataset• Coverage completed in 1997Coverage completed in 1997• Seamless grid of Seamless grid of

– 30 meter (1 arc-seconds)30 meter (1 arc-seconds)– 10 meter (1/3 arc-seconds)10 meter (1/3 arc-seconds)– 3 meter (1/9 arc-seconds)3 meter (1/9 arc-seconds)

• Overall vertical accuracy (RMSE) 2.44 mOverall vertical accuracy (RMSE) 2.44 m• Most areas in Virginia based upon 1960’s Most areas in Virginia based upon 1960’s

or older dataor older data



Elevation for the NationA National Research Council committee in 2007 • Found that existing elevation data are too old and lack

required accuracy• Proposed a national program called Elevation for the

Nation to parallel the existing Imagery for the Nation concept

• Recommended that LiDAR be the primary technology• Recommended that elevation data should be stored in the

National Elevation Dataset (NED)• Recommended that the database should include both the

original LiDAR point cloud and the edited bare-earth DEM

LiDAR (Light Detection and Ranging)

Multiple Returns



LiDAR Point Cloud

Bare Earth DEM

Digital Surface Model



LiDAR Projects 2010Project Jurisdictions Sq Mi Cost Funding

Eastern Shore AccomackNorthampton

660 $152K TNCUSGSUVA

Virginia’s ARRA Grant

GloucesterLancasterMatthewsMiddlesexNorthumberland

956 $500K USGS

USGS Additional Counties

Isle of WrightJames City King & QueenSuffolkSurryWilliamsburg

1,617 $450K USGS

Total 3,233 $1,102K



Elevation Data Clearinghouses• Bare-earth DEM

– NED National Elevation Dataset (USGS)

• Point-cloud data– CLICK Center for LiDAR Information

Coordination and Knowledge (USGS)



Existing Contours from VBMP Orthos• 2002, 2006/07 and 2009

VBMP orthophoto flights produced digital terrain models

• Primary purpose was orthorectification of the aerial images

• Can be used as input for further photogrammetric analysis to create contours (4-ft from 1-ft imagery and 2-ft from ½-ft imagery)

DTM – Digital Terrain Model



Elevation FIAT• The first Framework Initiative Action Team (FIAT) arising

from VGIN’s recently adopted 2010-2015 strategic plan• Implements Initiative 5 – Provide framework data layers• FIAT Tasks:

– Conduct an inventory of existing elevation datasets– Recommend elevation data standards and best practices– Promote coordination and collaboration on the development of

new elevation datasets– Promote data sharing and incorporate elevation data in the

existing clearinghouses



Thank You!

Questions?

1 Virginia Geographic Information Network Virginia’s Elevation Framework Layer Upcoming LiDAR...

Documents

Transcript of 1 Virginia Geographic Information Network Virginia’s Elevation Framework Layer Upcoming LiDAR...