NATRF 2022 AND LDP OCTOBER 11, 2017

Transcription

1 NATRF 2022 AND LDP OCTOBER 11, 2017

2 MODERNIZATION OF THE NSRS Why? Leaving passive control marks behind and relying solely on the CORS network for 3D positions: Older methodology relies on terrestrial (line-of-sight) observations NGS does not have the ability to monitor passive marks, they are easily destroyed NGS no longer has the resources to maintain or replace passive marks Evidence of Systematic Errors: Many years of geodetic observations has revealed systematic errors ranging from decimeters to meters Errors are being noticed and becoming issues with today s more accurate equipment (cm accuracy) NAD 83 is not geocentric with ITRF: GPS and WAAS navigation uses WGS 84 aligned to the ITRF Satellite orbits and other geospatial datasets use global reference frames 2

3 MODERNIZATION OF THE NSRS What s being replaced: Horizontal Horizontal Vertical NORTH AMERICAN TERRESTRIAL REFERENCE FRAME OF 2022 (NATRF 2022) PACIFIC TERRESTRIAL REFERENCE FRAME OF 2022 (PATRF 2022) NAVD 88 MARIANA NAD TERRESTRIAL 83(2011) REFERENCE FRAME OF 2022 (MATRF 2022) CARIBBEAN PRVD 02 NAD 83(MA11) TERRESTRIAL REFERENCE FRAME OF 2022 (CATRF 2022) VIVD09 NAD 83(PA11) ASVD02 Vertical NMVD03 GUVD04 IGLD 85 NORTH AMERICAN-PACIFIC GEOPOTENTIAL DATUM OF 2022 (NAPGD2022) THIS WILL INCLUDE THREE TIME DEPENDENT GEOID MODELS COVERING (GEOID 2022) NORTH AND CENTRAL AMERICA, HAWAII, ALASKA, GREENLAND, AND THE CARIBBEAN AMERICAN SAMOA GUAM AND THE COMMONWEALTH OF THE MARIANA ISLANDS Dru Smith: NGS 3

4 MODERNIZATION OF THE NSRS The new 2022 Reference Frames will be Plate Fixed: The new TRFs will agree with the ITRF (IGSxx) at the initial epoch. The new TRFs will diverge from ITRF by a few cm per year in order to stay plate-fixed. Future adjustments of the TRFs will be in the cm range. Time frames for new realizations and adjustment limits are still being determined. 4

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6 MODERNIZATION OF THE NSRS Each frame will get 3 parameters - Euler Pole Latitude - Euler Pole Longitude - Rotation rate (rad/yr) Used to compute time-dependent TRF2022 coordinates from timedependent ITRF coordinates. 6

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8 REPLACING NAD83 (THE HORIZONTAL ELEMENT) Goal is to align NAD 83 with the IGS08 origin of the ellipsoid where the GRS 80 ellipsoid fits on a global scale instead of the North American plate best fit solution we currently have in NAD83. NATRF2022 origin 1.5 meters NAD 83 ORIGIN Identically shaped ellipsoids (GRS-80) a = 6,378, meters (semi-major axis) 1/f = (flattening) Dave Doyle 8

9 LATTITUDE HORIZONTAL AND VERTICAL SHIFT NATRF2022 VS. NAD 83(2011) LONGITUDE ELLIPSOID HEIGHT Dru Smith: NGS 9

10 HORIZONTAL AND VERTICAL SHIFT NATRF2022 VS. NAD 83(2011) Columbus CORS Station COLB dx = 0.678m or 2.22 ft. dy = 1.410m or 4.62 ft. dz = 0.086m or 0.28 ft. Image of Helipad at ODOT HQ near COLB CORS Station Red Line: NAD 83 imagery on NAD 83 reference frame Green Line: Shift of Helipad to NATRF2022 but image remains on NAD 83 10

11 MODERNIZATION OF THE NSRS REPLACING NAVD 88 NAPGD2022 NORTH AMERICAN-PACIFIC GEOPOTENTIAL DATUM OF 2022 NEW DATUM BASED ON GRAVITY MODELS (THE GEOID) No passive marks/can use GNSS to position a benchmark GNSS BASED VERTICAL DATUM: Users with geodetic quality receivers can use OPUS or RTNs/ RTK to establish Orthometric Heights LEVELING NO LONGER REQUIRED TO ESTABLISH BENCHMARKS 11

12 MODERNIZATION OF THE NSRS REPLACING NAVD 88 ACCESS: easier to find the sky than a 60-year-old bench mark GNSS equipment is cheap and fast ACCURACY: easier to trust the sky than a 60-year old bench mark immune to passive mark instability Proposed accuracy of 2 cm over much of the United States GLOBAL STANDARDS: systematic errors of many meters across the US aligns with GPS, international efforts aligns with Canada, Mexico 12

13 MODERNIZATION OF THE NSRS TRANSITION TO THE FUTURE: GRAV-D Gravity for the Redefinition of the American Vertical Datum Official NGS policy as of Nov 14, 2007 $38.5M over 10 years Airborne Gravity Snapshot Absolute Gravity Tracking Re-define the Vertical Datum of the USA by 2022 Approximately 62% Complete (Sept. 2017) 13

14 MODERNIZATION OF THE NSRS GRAV D PROGRESS Green: Available data and metadata Blue: Data being processed Orange: Data collection underway White: Planned for data collection 14

15 REPLACING NAVD88 GRAV-D GRAVITY FOR THE REDEFINITION OF THE AMERICAN VERTICAL DATUM GRAV-D PROJECT Errors exist in NAVD 88: 50cm average 100cm CONUS tilt 1-2m average in Alaska Changing from a leveling-based to geoid/gnss-based vertical datum requires an updated accurate, nationwide gravity survey using airborne gravity meters. 15

16 ODOT S EFFORTS TO IMPLEMENT LOW DISTORTION MAP PROJECTIONS FOR ODOT PROJECTS 16

17 WORKING WITH STATE PLANE COORDINATES OR HOW TO MAKE THE EARTH FLAT SURVEYORS AND MAP MAKERS HAVE HAD TO CREATE MAPS OF THE EARTH FOR CENTURIES. THE WAY WE DRAW A CURVED SURFACE ON A FLAT PLAIN IS BY USING MAP PROJECTIONS. AS SURVEYORS WE ARE AWARE THAT WE CANNOT REPRESENT A CURVED SURFACE ON A FLAT PLAIN WITHOUT SOME DISTORTION. 17

18 THE CURRENT STATE PLANE COORDINATE SYSTEM Linear distortion due to Earth s curvature Projection surface (secant) Ellipsoid surface Grid length greater than ellipsoidal length (distortion > 0) Grid length less than ellipsoidal length (distortion < 0) Maximum projection zone width for balanced positive and negative distortion 18

19 THE CURRENT STATE PLANE COORDINATE SYSTEM Linear distortion due to Elevation Ground surface Projection surface (secant) Ellipsoid surface Grid length greater than ellipsoidal length (distortion > 0) Grid length less than ellipsoidal length (distortion < 0) Maximum projection zone width for balanced positive and negative distortion 19

20 THE CURRENT STATE PLANE COORDINATE SYSTEM ISSUES WITH THE USE OF CURRENT STATE PLANE COORDINATE SYSTEM: CURRENT STATE PLANE COORDINATE SYSTEM DESIGNED AT 1 : 10,000 ACCURACY TODAYS EQUIPMENT IS MUCH MORE ACCURATE THAN THIS OAC : SETS THE MINIMUM STANDARD FOR BOUNDARY SURVEYS AT 1 : 10,000 MINIMUM ACCURACY. THIS EATS UP YOUR ERROR BUDGET RATHER QUICKLY GRID DISTANCES DO NOT REFLECT TRUE GROUND DISTANCES NEED TO SCALE PROJECTS TO MINIMIZE DISTORTION BETWEEN GRID AND GROUND THIS SCALING IS DONE ON A PROJECT BY PROJECT BASIS NO STANDARD SCALE FACTOR USED FOR MULTIPLE PROJECTS PROJECTS IN CLOSE PROXIMITRY TO EACH OTHER HAVE DIFFERENT SCALE FACTORS AND DO NOT FIT EACH OTHER DOES NOT WORK SEAMLESSLY WITH OTHER PRODUCTS (GOOGLE EARTH, ESRI, OSIP IMAGERY, CADD PLATFORMS) 20

21 THE CURRENT STATE PLANE COORDINATE SYSTEM IS IT TIME TO RE-THINK STATE PLANE COORDINATES? CAN WE DEVELOP A COORDINATE SYSTEM THAT WOULD ESSENTIALLY ELIMINATE DISTORTION (OR MAKE IT SO INSIGNIFICANT THAT IT CAN BE IGNORED)? CAN WE WORK SEAMLESSLY BETWEEN OUR GPS EQUIPMENT AND TOTAL STATION WITHOUT CALCULATING A SCALE FACTOR? CAN WE INCORPORATE GIS DATA INTO OUR SURVEYS (OR INCORPORATE OUR SURVEYS INTO GIS) SEAMLESSLY? 21

22 THE CURRENT STATE PLANE COORDINATE SYSTEM THE ANSWER IS: YES WE CAN! HOW? 22

23 THE CURRENT STATE PLANE COORDINATE SYSTEM LET S RE-THINK HOW WE PROJECT LAT/LONG TO PLANE COORDINATES

24 THE CURRENT STATE PLANE COORDINATE SYSTEM BY LOOKING AT OUR STATE IN A DIFFERENT WAY INSTEAD OF DIVIDING OHIO INTO TWO ZONES (NORTH AND SOUTH) LET S LOOK AT HOW CURVATURE AND ELEVATION AFFECT LINEAR DISTORTION:

25 MAXIMUM ZONE WIDTH FOR SECANT PROJECTIONS MAXIMUM LINEAR HORIZONTAL DISTORTION MILES Parts per Million Feet per Mile Ratio 35 MILES ± 5 ppm ± 0.03ft. / mile 1 : 200, MILES ± 10 ppm ± 0.05ft. / mile 1 : 100, MILES ± 20 ppm ± 0.10ft. / mile 1 : 50, MILES ± 50 ppm ± 0.30ft. / mile 1 : 20, MILES ± 100 ppm ± 0.50ft. / mile 1 : 10,000 Dave Minkel and Michael Dennis NGS/NOAA 25

26 HEIGHT ABOVE AND BELOW PROJECTION SURFACE LINEAR DISTORTION DUE TO ELEVATION FEET Parts per Million Feet per Mile Ratio ± 100 ft. ± 4.8 ppm ± 0.03ft. / mile 1 : 209,000 ± 400 ft. ± 19 ppm ± 0.10ft. / mile 1 : 52,000 ±1,000 ft. ± 48 ppm ± 0.25ft. / mile 1 : 21,000 Dave Minkel and Michael Dennis NGS/NOAA 26

27 LOW DISTORTION MAP PROJECTION Ground surface Typical State Plane surface Low Distortion surface Ellipsoid surface Grid length greater than ellipsoidal length (distortion > 0) Grid length less than ellipsoidal length (distortion < 0) Typical State Plane Zone width for balanced positive and negative distortion Dave Minkel and Michael Dennis NGS/NOAA 27

28 LOW DISTORTION MAP PROJECTIONS MAHONING PROJECTIONS ARE DESIGNED BASED ON THE SHAPE OF THE COUNTY. COUNTIES THAT LIE PREDOMINANTLY EAST AND WEST RECEIVE LAMBERT CONFORMAL CONIC PROJECTIONS COUNTIES THAT LIE PREDOMINANTLY NORTH AND SOUTH RECEIVE TRANSVERSE MERCATOR PROJECTIONS 28

29 LOW DISTORTION MAP PROJECTIONS SUMMIT PROJECTIONS ARE DESIGNED BASED ON THE SHAPE OF THE COUNTY. COUNTIES THAT LIE PREDOMINANTLY NORTH AND SOUTH RECEIVE TRANSVERSE MERCATOR PROJECTIONS 29

30 The current workflow WORKFLOW 1.) Select your system (NAD83) and your Zone (Ohio North or South) 2.) Calculate your Scale Factor using one of the various methods outlined in the Survey and Mapping Specifications and enter it into the Data Collector 3.) Enter the Coordinates you are going to scale about (0,0) VERY IMPORTANT STEP!!! 30

31 WORKFLOW The Low Distortion System workflow 1.) Select ODOT LDS 2.) Select the county you are working in 31

32 LOW DISTORTION MAP PROJECTIONS WHERE ARE WE AND WHERE ARE WE GOING? MAP PROJECTIONS FOR ALL 88 COUNTIES ARE COMPLETE. CURRENTLY CONDUCTING FIELD TESTS FOR QUALITY CONTROL AND ASSURANCE. PROJECTING TESTING TO BE COMPLETED BY JULY 1, MAKE ADJUSTMENTS TO PROJECTIONS AND UP-DATE MAPS BY DECEMBER MAKE PROJECTIONS AVAILABLE ON CADD AND MAPPING WEB SITE. 32

33 QUESTIONS Last updated 10/19/