POTENTIAL CONSTELLATION DEVELOPMENTS(10 Years??)GPS MODERNIZATION – BLOCK IIR-M & IIIGLONASS ENHANCEMENTS EUROPEAN UNION - GALILEOCHINA - COMPASS100+ SatellitesSecond and Third Civil Frequency – GPSMore Robust Signal TransmissionsReal-Time Unaugmented 1 Meter (or better!) Accuracy
ACCURATE -- cm accuracy on a global scale ACCURATE -- cm accuracy on a global scaleMULTIPURPOSE -- Supports Geodesy, Geophysics, Land Surveying, Navigation, Mapping, Charting and GIS activitiesACTIVE -- Accessible through Continuously Operating Reference Stations (CORS) and derived productsINTEGRATED -- Related to International services and standards (e.g. International Earth Rotation and Reference Systems Service, International GNSS Service etc.)
A set of constants specifying the coordinate system used for geodetic control, i.e., for calculating coordinates of points on the Earth. Specific geodetic datums are usually given distinctive names. (e.g., North American Datum of 1983, European Datum 1950, National Geodetic Vertical Datum of 1929) A set of constants specifying the coordinate system used for geodetic control, i.e., for calculating coordinates of points on the Earth. Specific geodetic datums are usually given distinctive names. (e.g., North American Datum of 1983, European Datum 1950, National Geodetic Vertical Datum of 1929)
HORIZONTAL - HORIZONTAL
- 2-D (Latitude and Longitude) (e.g. NAD 27, NAD 83 (1986))
- VERTICAL/GEOPOTENTIAL
- 1-D (Orthometric Height) (e.g. NGVD 29, NAVD 88, Local Tidal)
- GEOMETRIC
- 3-D (Latitude, Longitude and Ellipsoid Height)
- Fixed and Stable(?) - Coordinates seldom change
- (e.g. NAD 83 (1993), NAD 83 (2007))
- also
- 4-D (Latitude, Longitude, Ellipsoid Height, Velocities) Coordinates change with time
- (e.g. ITRF00, ITRF05)
8 Constants 8 Constants3 – specify the location of the origin of the coordinate system.3– specify the orientation of the coordinate system.2 – specify the dimensions of the reference ellipsoid
A set of fundamental elevations to which other elevations are referred. A set of fundamental elevations to which other elevations are referred.Datum TypesTidal – Defined by observation of tidal variations over some period of time (MSL, MLLW, MLW, MHW, MHHW etc.)(NOS Center for Operational Oceanographic Products and Services) (CO-OPS)Geodetic – Tided to Local Mean Sea Level at one or more points at some epoch(NAVD 88, IGLD85)
STATE PLANE AND UNIVERSAL TRANSVERSE MERCATOR GRID COORDINATES ARE A DIRECT MATHEMATICAL CONVERSION FROM LATITUDE AND LONGITUDE TO A CARTESIAN NORTHING AND EASTING (Y & X) COORDINATE SYSTEM, AND MUST MAINTAIN THE SAME DATUM TAG [e.g. NAD 27 or NAD 83] AS THE LATITUDE AND LONGITUDE)
State plane coordinates are the projection of latitudes and longitudes from the GRS80 ellipsoid State plane coordinates are the projection of latitudes and longitudes from the GRS80 ellipsoid
Developed by U.S. Coast and Geodetic Survey from a request in 1933 from the North Carolina Department of TransportationTwo basic map projections used:- Lambert Conformal Conic – States or parts of states that have a more East-West orientation
- Transverse Mercator – States or parts of states that have a more North-South orientation
Zones typically 154 miles wide – this limits the maximum geodetic to grid distance distortion to 1:10,000All coordinate values in U.S. Survey FeetConversions to/from latitude & longitude calculated using tables (e.g. USC&GS Special Publication. 316 Plane Coordinate Projections Tables – New Jersey)State Plane Coordinates by Automatic Data Processing (USC&GS 62-4)
Geometric parameters of original SPC zones left unchanged unless requested by “the State”All states get new false northing and false easting defined in meters.All values in meters – conversions to feet defined by individual state legislation or Federal Register Notice 1 m = 3.2808333333. U.S. Survey Feet 1 m = 3.2808398950 International Feet
UTMUTMS (Both NAD 27 & NAD 83)http://www.ngs.noaa.gov/TOOLS/utm.shtmlCORPSCON (Both NAD 27 & NAD 83)http://crunch.tec.army.mil/software/corpscon/corpscon.htmlSTATE PLANE COORDINATESGPPCGP (NAD 27 only)SPCS83 (NAD 83 only)http://www.ngs.noaa.gov/TOOLS/spc.shtmlCORPSCON (Both NAD 27 & NAD 83)http://crunch.tec.army.mil/software/corpscon/corpscon.html
1. WHAT DATUM ARE THE EXISTING COORDINATES/HEIGHTS ON? 1. WHAT DATUM ARE THE EXISTING COORDINATES/HEIGHTS ON?2. WHAT DATUM DO I WANT THE NEW COORDINATES/HEIGHTS ON?3. HOW LARGE A GEOGRAPHICAL AREA DO I WANT TO CONVERT AT ONE TIME?4. HOW MANY POINTS ARE COMMON TO BOTH DATUMS?5. WHAT IS THE DISTRIBUTION OF THE COMMON POINTS?6. HOW ACCURATE ARE THE EXISTING COORDINATES/HEIGHTS? 0.01 Meter7. HOW ACCURATE DO I WANT THE NEW COORDINATES/HEIGHTS?
SATISFIES ALL USERS’ REQUIREMENTS CAPABLE OF TRANSFORMING LARGE DATASETS NEAR-REAL TIME APPLICATIONS SIMPLE - METHOD SHOULD NOT REQUIRE AN EXPERT OR DECISIONS TO BE MADE ACCURATE
MOLODENSKY MOLODENSKYFor continental regions accuracy can be +/- 8 to 10 metersDoes not model network distortions very well.Assumes heights in both systems are ellipsoidal (NAD 27 did not have ellipsoidal heights).
VERTCON(NGVD 29 only)NADCON(NAD 27, OLD HAWAIIAN, PUERTO RICO, 3 ALASKA ISLANDS)(HPGN/HARN)
MOLODENSKY MOLODENSKYConverts latitude, longitude and ellipsoidal height to X,Y,Z Earth-Centered Coordinates.Applies a 3-dimensional change in the origin (dX, dY,dZ)Applies a change in the size and shape of the reference ellipsoidConverts new X,Y,Z Earth-Centered Coordinates back to latitude, longitude and ellipsoidal height
MOLODENSKY MOLODENSKYADJUSTED vs. TRANSFORMEDStation: OBSERVATORY (HV7843) LATITUDE LONGITUDE 38-12-06.79868 077-22-22.35067 - PUBLISHED 38-12-06.59040 077-22-22.34223 - MOLODENSKY .20828” .00844” 6.422 m 0.205 m THIS CORRESPONDS TO A POSITIONALDIFFERENCE OF 6.425 m (21.08 ft)
NADCON NADCONADJUSTED vs. TRANSFORMEDStation: OBSERVATORY (HV7843) LATITUDE LONGITUDE 38-12-06.79868 077-22-22.35067 - PUBLISHED 38-12-06.79920 077-22-22.34823 - NADCON .00052” .00244” 0.016 m 0.059 mTHIS CORRESPONDS TO A POSITIONALDIFFERENCE OF 0.061 m (0.20 ft)
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