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New Geometric Datum: New Geometric Datum: plansplans
Modernizing the U.S.Modernizing the U.S.National Spatial Reference SystemNational Spatial Reference System
FGCSSan Diego, CaliforniaMonday 11 July 2011
Geodetic control is the foundation for all geospatial products.
Geodetic Control is the critical “basemap” layer
for GIS applications
Coordination begins with good coordinates
Sour
ce: Z
uric
h-A
mer
ican
Ins
uran
ce G
roup
Crustal velocitiesPassive networks are aging
(instability, accessibility, loss)
How accurate is the NSRS?
stable N.A.
world avg.
NAD83 vs GNSS
2.2 meters
NAD 83Origin
Earth’s
Surface
ITRFOrigin
( Identically shaped ellipsoids )
New geometric datum minus NAD 83 (horizontal)
New geometric datum minus NAD 83 (ellipsoid height)
mm/year
1.6 meter shift on a 1:25,000 map
modern users abuse map scale
NAD83 and GNSS lat/lon lattices are
0.006 cm apart
Accurate and seamless!!
Optimized for my project!!
the path to a new geospatial datum• SCIENCE:
– participate in international geodesy– maintain core geodetic infrastructure– define stable North America, plate motions, local issues
• OUTREACH:– illustrate limitations of current system– geospatial summits with FGCS, ACSM, ION, etc.– assist key stakeholders to identify use cases, issues
• TOOLS:– dependable models– GEOID, NADCON, H(+V) TDP exploitable via vendor toolkits– services for RTN operators
the path to a new geospatial datum• DEFINE:
– Fixed to plate at what epoch? Update frequency/tolerance?– Coordination with international community, Canada, Mexico, etc.– FGDC vote to adopt, Federal Register Notice, formal report, & FAQ
• IMPLEMENT:– Products (datasheets, OPUS, GEOIDs, maps, charts, projects)– Toolkit (NADCON, TDP) and best practices– Legacy plan: how much support for USSD, NAD27, NAD83
• TIME FRAME:– Follow in synch with geopotential datum effort– Note, NAD27 is still in use.
Geospatial summit 2012
• What do you want to talk about?
geodesy.noaa.gov/2010Summit/•Presentations •Handouts •Proceedings
New Vertical Datum: plans, status, GRAV-D updateFGCS
San Diego, CA.July 11, 2011
Mark C. EcklMark C. EcklNGS Chief of Observation and Analysis Division,NGS Chief of Observation and Analysis Division,
New Vertical Datum Project ManagerNew Vertical Datum Project Manager
NORTH AMERICAL VERTICAL DATUM 1988
NEW VERTICAL DATUM(Topics)
• Rationale for the New Vertical Datum
• Components of the Project Plan
• Estimated Outcome
NEW VERTICAL DATUM(Rationale)
• To be consistent with the shift in the geometric reference frame/ellipsoid (2022)
• Improvement in our technical abilities in reference surface realization (geopotential gravimetric reference surface - 1cm accuracy of geoid (GNSS/GRAV-D))
• The new geopotential reference surface will be aligned with the geometric reference frame/ellipsoid (i.e., no hybrid geoid)
• A move away from differentially leveled passive control as the defining mechanism of the reference surface
NEW VERTICAL DATUM(Rationale)
• The technology to make accurate vertical heights measurements with GNSS technology
• To provide vertical access to formerly prohibitive places
• To allow monitoring of physical or geophysical datum deformation
NEW VERTICAL DATUM(Components)
• Design and adopt new geometric reference frame (Geometric Datum Project)
• Realize new geometric datum with existing passive/active control, i.e., a horizontal (geometric) adjustment
• Definition of the W0 surface as the new datum reference surface
• Build a gravimetric geoid with an overall accuracy of 1 cm
GRAV-D Processing Update• Alabama (‘08) and 2008 Alaska survey already
delivered to Geoid team (Newton v1.1)
• Next major version of aerogravity processing software is complete (Newton 1.2)
• Newton 1.2 data for Alabama and Louisiana will be delivered to geoid team by early July; other surveys will quickly follow
• LA/AL airborne gravity data will release publicly in next month via a web page designed to share data
• Still partnering for flights; seeking a dedicated plane
University of New Orleans June 20-21, 2011
Determining Elevations with GNSS Improvements
to the Geoid Models27
GRAV-D Survey Plans
• FY 2011:
– Alaska
– California/Oregon coastline
– Eastern Great Lakes Region
– As of June 1, 13.45% of total area has been surveyed
• FY2012:
– Great Lakes region
– Washington State
– California
• FY2013:
– Finish Great Lakes
– TBD
Alaska FY11 West Coast FY11-12
FY11-13 Great Lakes Plan
FY10 = GreenFY11 = BlueFY12 = OrangeFY13 = White
(FY11 Already Flown)
NEW VERTICAL DATUM(Components)
• Studies of:• Geoid slope validations• Geoid bias• Geoid long term monitoring (i.e., change detection)• Gravity measurement systems accuracy assessments• GNSS ellipsoid absolute height measurements• GNSS differential ellipsoid height measurements
• Prepare a forward and backward vertical datum conversion strategy - points and maps/charts (ref: NC Pilot Project)
NEW VERTICAL DATUM(Components)
• Work with FGCS for adoption of new/updated (FGCS Vertical Working Group):• Standards of Accuracy• Specifications• Procedures, and• Guidelines
• Outreach
NEW VERTICAL DATUM(Outcome)
NEW VERTICAL DATUM(Goal)
Increase the accuracy and utility of the vertical datum by referencing a global geopotential surface, related to global sea-level, which is accessible through space-based measurement systems and which maintains the differential precision associated with any NGS adopted vertical datum.