Now & the Future of Geodesy in Hawaii for the GIS Users Edward E. Carlson Pacific Region Geodetic Advisor NOAA’s National Geodetic Survey
Now & the Future of Geodesy in Hawaii for the GIS Users
Edward E. CarlsonPacific Region Geodetic Advisor
NOAA’s National Geodetic Survey
http://www.bing.com/videos/search?q=Geodesy%20youtube&FORM=O1HV1
What is geodesy?Geodesy is the science of measuring
and monitoring the size and shape of
the Earth.
The Earth is an irregular surface, difficult
to model.
Accurate positions are required for a wide
variety of applications.(e.g. monitoring climate change impacts and sea level change)
Why is geodesy important?
Geodetic control (NSRS) is the foundation for all geospatial products.
Without a geodetic control “base map” layer, GIS applications will not work properly!
Accurate positions beginwith accurate coordinates!
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TIME NETWORK LOCAL NETWORK SPAN ACCURACY ACCURACY
Old Hawaiian Datum/ 1927-1986 10 Meters First-Order (1 part in 0.1 million)
NAD 27 NAD 83(1986) 1986-1993 1 Meter First-Order(1 part in 0.1 million)
NAD83(1993) 1987-1997 0.1 Meter B-Order(1 part in 1 million) HARN A-Order (1 part in 10 million)
NAD83(PACP00) 1994 - 2111 0.02 Meter - Horizontal CORS 0.04 Meter - Ellipsoid Height
NAD83(2011,PA11,MA11) 2111 - 0.01 Meter - Horizontal CORS 0.02 Meter - Ellipsoid Height
National Spatial Reference System(NSRS) Improvements
Hawaiian Islands
445.518 m
451.588 m451.359 m
461.047 m
Datum Differences
OLD HAWAIIAN DATUM to NAD83(1986)
Hawaiian Islands
0.885 m
1.38 m1.57 m
1.31 m
Datum Differences
NAD83 (1986) to NAD83 (1993) / HARN
NAD 83(2011) epoch 2010.00• Multi-Year CORS Solution (MYCS)
– Reprocessed all CORS GPS data Jan 1994-Apr 2011– 2264 CORS & global stations– NAD 83 computed by transformation from IGS08
• National Adjustment of 2011 (NA2011)– New adjustment of GNSS passive control– GNSS vectors tied (and constrained) to CORS
NAD 83(2011) epoch 2010.00– Approximately 80,000 stations and
400,000 GNSS vectors• Realization SAME for CORS
and passive marks• This is NOT a new datum! (still NAD 83)
7/13/2014 92014 Esri AEC Summit
CONUS CONUS
AlaskaAlaska
Pacific Pacific (MA11)(MA11)
Pacific (PA11)Pacific (PA11)
Median accuracy (95% conf.):0.9 cm horiz, 1.5 cm height
Hawaiian Islands
NAD83(PACP00) – NAD83(PA11) = 0.02mNAD83(PA11) - WGS84(ISG08) = 2.42mNAD83(PACP00) – WGS84(ITRF00) = 1.80m
NAD83(PACP00) – NAD83(PA11) = 0.02mNAD83(PA11) - WGS84(ISG08) = 2.44mNAD83(PACP00) – WGS84(ITRF00) = 1.87m
NAD83(PACP00) – NAD83(PA11) = 0.02mNAD83(PA11) - WGS84(ISG08) = 2.45mNAD83(PACP00) – WGS84(ITRF00) = 1.88m
NAD83(PACP00) – NAD83(PA11) = 0.02mNAD83(PA11) - WGS84(ISG08) = 2.47mNAD83(PACP00) – WGS84(ITRF00) = 1.91m
NGA did a new definition of WGS84 in 2012aligned with - IGS08 epoch 2005.0
Datum Differences
NAD83(MARP00) – NAD83(MA11) = 0.08mNAD83(MA11) - WGS84(ISG08) = 1.13mNAD83(MARP00) – WGS84(ITRF00) = 1.05m
NAD83(PACP00) – NAD83(PA11) = 0.16mNAD83(PA11) - WGS84(ISG08) = 3.05mNAD83(PACP00) – WGS84(ITRF00) = 2.45m
NAD83(MARP00) – NAD83(MA11) = 0.03mNAD83(MA11) - WGS84(ISG08) = 1.23mNAD83(MARP00) – WGS84(ITRF00) = 1.15m
Datum Differences
The National Geodetic Survey Ten-Year PlanSupport the users of the National Spatial Reference System.
Modernize and improve the National Spatial Reference System.
Expand the National Spatial Reference System stakeholder base through partnerships, education, and outreach.
Develop and enable a workforce with a supportive environment.
Improve organizational and administrative functionality.
http://www.geodesy.noaa.gov/web/news/Ten_Year_Plan_2013-2023.pdf
Both a new geometric and a new geopotential (vertical) datum will be released in 2022.
The realization of the new datums will be through GNSS receivers.
NGS will provide the tools to easily transform between the new and old datums.
Modernizing the NSRSPositioning America in a dynamically changing world
How will the new datums affect you?
The new geometric datum will change latitude, longitude,
and ellipsoid height by between
1 and 2 meters.
The new vertical (geopotential)
datum will change heights on
average 50 cm (20''), with
a 1-meter (39'') tilt towards
the Pacific Northwest.
NAD 83(2011) to NAD 83(2011) to IGS08 at epoch 2022.0IGS08 at epoch 2022.0
NAD 83(PA11) to NAD 83(PA11) to IGS08 at epoch 2022.0IGS08 at epoch 2022.0
NAD 83(2011) to NAD 83(2011) to IGS08 at epoch 2022.0IGS08 at epoch 2022.0
Changes between in New Datum• NSRS coordinates change?
– North America plate (CONUS and AK): Approx 0.8 to 1.6 m
– Pacific plate: Approx 3.4 (Midway) to 4.3 m (American Samoa)
– Mariana plate: Approx 1.1 to 1.4 m
• NSRS ellipsoid height change?– Approx -1.9 m (Puerto Rico) to +2.0 m (Guam)
Hawaii
Alaska “CONUS”
Puerto Rico / Virgin Islands
Guam / Northern Marianas
American Samoa
Planned GRAV-D Coverage
What to do now!!! Move to newest realizations.
NAD 83(2011,PA11,MA11) epoch 2010.00USGG12 (gravimetric geoid) / GEOID12A
Require/provide complete metadata for all mapping contracts.How did they get the positions/heights? Document it!
Obtain precise ellipsoid heights on bench marks. (OPUS-DB, contact NGS Geodetic Advisor)Improves hybrid geoid models and provides “hard points” in new vertical datum.Follow new NGS Guidelines when released.
Move away from passive marks to GNSS.Especially, move away from classical passive control.
Move from NGVD 29 to NAVD 88. (For CONUS only)Understand the accuracy of VERTCON in your area.
Does this stuff really matter?• Significant for accuracies better than ~1-2 m
– Can be problem for combining accurate datasets– Requires understanding of modern datums– Be careful when using “WGS 84”
• Which realization? At what epoch? At what level of accuracy?
• Things are moving, and it can make a difference– e.g., San Diego moving 4.0 cm/yr NW w.r.t. Phoenix, AZ
• GNSS becoming more precise– Autonomous positions soon better than 1-2 m– But accuracy another issue… with respect to what?
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