VRSWG Update

Renee ShieldsHeight Modernization Manager

National Geodetic SurveyJanuary 10, 2012

• Identify common objectives, and find opportunities for cooperative projects, tasks: water level gage datum updates, sea level change or subsidence studies

• Identify Products and Services within each agency impacted by new vertical datums: flood maps

• Update existing guidelines, standards, specifications to support transition to new datums

• Education, Outreach, Capacity Building for users

Vertical Reference System Work Group Work Plan

• Quarterly teleconferences - next meeting April 5, 2011

• Developed worksheet for each agency to identify their products/services that rely on vertical datums

• Identify venues for outreach/education

VRSWG Accomplishments: May 2010-Present

• Infrastructure– Special Projects: So LA, MSDOT leveling and GPS, TN leveling, WI

Statewide leveling adjustment

– NA2011 – consistent ellipsoid heights

– Updates to NGS Datasheet formats

• Announcement on NGS website

• Implementation to coincide with NA2011 release

Relevant Height Modernization / NGS Accomplishments: July 2012-Present

Datasheet Format Changes

Move ell ht and epoch info into top box, add datum tags

Note when GPS Ortho Ht computed with previous geoid model, and provide that model ht

Better way to quantify accuracies

Current Datasheet

http://www.ngs.noaa.gov/web/news/Datasheet_Format_Change.shtml

• Models/Tools

– GEOID12

– GRAV-D

– TX Geoid Slope project

– VDatum

– HTDP

– VTDP

– OPUS DB, Projects, etc.

Relevant Height Modernization / NGS Accomplishments: July 2012-Present

•Insert VDATUM slides here

Relevant Height Modernization / NGS Accomplishments: July 2012-Present

• HTDP (Trans4D)/VTDP– Plan to include a vertical component with HTDP = Trans4D

• Developed by Jeff Freymueller at UAF with Richard Snay

• Uses primarily CORS velocities

• Not ready for Prime Time in areas like Gulf Coast

– Leveling projects in Gulf Coast region, added to NGS IDB since 1995, being incorporated into VTDP

Relevant Height Modernization / NGS Accomplishments: July 2012-Present

• Guidelines/Specifications– Guidelines for analysis and adjustment of survey data in areas

prone to crustal motion

– NC/FEMA Floodplain mapping pilot

Relevant Height Modernization / NGS Accomplishments: July 2012-Present

Floodplain Mapping Pilot Project• Goals:

– Analyze how FEMA floodplain mapping will be affected by the release of the new datums

– Provide recommendations for FEMA, cooperating partners and NGS

• Selected one stream with existing detailed study in coastal area

• Two Part Method:– Converted data to “proxy” datums

• ITRF 2005/GRS80 State Plane 3200 USGG2009– Analyzed impacts to floodplain mapping

• Derived products (DEM creation from LiDAR)• Watershed size difference• Floodplain boundary and Base Flood Elevation

change• Bridge height sensitivity

11

Pilot Project: Conclusions

12

• Significant coordinates shift Horizontal: 2.716 ft/0.828 mVertical: -0.947 ft/-0.289 m

• Larger impact on higher accuracy elevation data

• DEMs derived from LiDAR can be transformed directly for hydrology, may use same models

• Minimal changes in the floodplain, will depend on the location, the mapping method, and engineering judgment

• Existing models will need to be revised to use ground data collected in new datums

• While this study provides the first look at the expected effects, additional studies are warranted prior to the 2022 modernization

• The development of an implementation plan is extremely important for FEMA and other agencies

• Important to have a clear message and communication to constituents

Full Report: http://www.ngs.noaa.gov/PUBS_LIB/Floodplain_Pilot_Project_Final.pdf

• Outreach/Education– Geospatial Summit

– Monthly Height Mod teleconferences to inform users – value-added with guest speakers

– Website completed

– Lidar Forum – August 2011

– Height Mod Partner meeting – August 2011

Relevant Height Modernization / NGS Accomplishments: July 2012-Present

• First draft of overall Plan complete and being reviewed

• Strategic plan development underway

• Operating plans will be developed from these

• Emphasize coordination with federal partners and local partners

• Develop budget strategies

National Height Modernization Program Plan

Questions

Renee ShieldsHeight Modernization Manager301-713-3231, x116Renee.Shields@noaa.gov