Height Mod Overview

1
NOAAs National Geodetic Survey National
Height Modernization and GRAV-D Putting It All
Together Height Modernization Forum American
Congress of Surveying and Mapping Salt Lake
City, Utah February 20, 2009 Renee
Shields Height Modernization Manager
2
Overview

• Height Modernization in the beginning
• Elements of Height Modernization
• Partnership activities
• Science of Height Mod
• That was then The future of height mod

3
Height Matters
Image credit AP Photo/Rick Bowmer
4

• Transportation
• Mapping and Charting
• Construction, Engineering
• Recover decimated control networks

5
Measure, Monitor, Model - Crustal Motion/
Subsidence/Isostatic Rebound /Seasonal changes
6
Flooding, coastal, waterway navigation
applications

• FEMA Map Modernization Program
• Flood Insurance Rate Maps
• Elevation Certificates
• Evacuation Route Surveys
• Relating tidal and land datums for waterway
  navigation and coastal resource applications

7
DEMs, Geoid modeling
8
New and Non-traditional Applications

• Geographic Information Systems (GIS)
• Precision Farming
• Fleet Management
• Machine Control

9
Benefits

• Emergency response
• Coastal resilience, habitat restoration
• Damage mitigation
• Water management, delivery dams, levees
• Water levels relative sea level change
• Accurate geospatial foundation for GIS
• Storm surge, inundation modeling
• Reduce design and construction costs for
  engineering projects
• Accurate determination of floodplains maximize
  insurance cost/benefit
• Improve agricultural yields
• Ensure safe low-visibility aircraft landings
• Ensure safe overhead and under-keel clearance on
  waterways

10
Mission of NGS

• To define, maintain and provide access to the
  National Spatial Reference System to meet our
  nations economic, social, and environmental needs

http//geodesy.noaa.gov/INFO/ngs_tenyearplan.pdf
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Height Modernization Objective
NSRS
NSRS

NAVD88
GEODETIC CONTROL
12
Height Modernization is

• the establishment of accurate, reliable heights
  using GNSS technology in conjunction with
  traditional leveling, gravity, and modern remote
  sensing information.

13
The Roots of Height Modernization

• In 1994 - First meeting held in Sacramento, CA
• Some heights in CA in error by more than a meter
• GPS could be immediately used to meet some of
  Californias requirements
• Necessary for the implementation of NAVD 88
• In 1998, 1.0 M was added to NGS budget to
  perform Height Modernization Study

14
The Roots of Height Modernization

• In 2000, 500K added to NGS budget for Height
  Modernization planning
• In 2001, 2.25M added to NGS budget
• to implement Height Modernization in NC
• to support the California Spatial Reference
  Center (CSRC)
• to support NGS related Height Modernization
  activities
• Also in 2001, NOAA is directed to work with LA
  and WI to assess their requirements for Height
  Modernization

15
Height Modernization Appropriations (FY01-FY08)
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FY08 Height Modernization - Recipients

• State and Local Governments
• North Carolina Geodetic Survey
• South Carolina Geodetic Survey
• State Departments of Transportation Wisconsin,
  Michigan, Minnesota, Colorado
• Alabama Department of Revenue
• Washington State Department of Natural Resources
• Arizona State Land Development
• Academic Institutions
• Scripps Oceanographic Institute
• North Carolina AT University
• Louisiana State University
• University of Southern Mississippi
• Texas AM Corpus Christi
• Morehead State University
• University of Illinois
• New Mexico State University

17
Participating and Interested States
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NAVD88 Heights

• How do we get heights?
• Most accurate sub-cm
• Most time-consuming and costly
• How can we get good heights more easily?

NAVD88 Heights - Conventional Leveling
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enter GNSS
Can we get accurate heights with GNSS?
20
Ellipsoid, Geoid, and Orthometric Heights
H Orthometric Height (leveling)
H h - N
h Ellipsoidal Height (GPS)
N Geoid Height (model)

h (NAD83)
TOPOGRAPHIC SURFACE
(NAVD88) H
N
Geoid Height (GEOID03)
Ellipsoid
Geoid
21
Guidelines
Available On-Line at the NGS Web
Site www.ngs.noaa.gov/PUBS_LIB/pub_index.html
22
Components of NGS-58

• Equipment requirements
• Field Procedures/Data Collection Parameters
• Basic Control Requirements
• Processing/Analysis Procedures

23
Height Modernization Project
HARN - Average 50km, max 75km
Secondary - Average 12-15km, max 15km
Local Average 6-8 km, max 10km
Primary 20-25km, max 40km
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NGS Datasheet Leveling/GPS

• 1 National Geodetic Survey, Retrieval
  Date JANUARY 26, 2009
• LP0230
  
• LP0230 CBN - This is a Cooperative
  Base Network Control Station.
• LP0230 DESIGNATION - E 174
• LP0230 PID - LP0230
• LP0230 STATE/COUNTY- UT/SALT LAKE
• LP0230 USGS QUAD - FARNSWORTH PEAK (1972)
• LP0230
• LP0230 CURRENT SURVEY
  CONTROL
• LP0230 _________________________________________
  __________________________
• LP0230 NAD 83(2007)- 40 43 40.61719(N) 112
  10 23.51247(W) ADJUSTED
• LP0230 NAVD 88 - 1295.727 (meters)
  4251.06 (feet) ADJUSTED
• LP0230 _________________________________________
  __________________________
• LP0230 EPOCH DATE - 2002.00
• LP0230 X - -1,827,153.513 (meters)
  COMP
• LP0230 Y - -4,483,296.800 (meters)
  COMP
• LP0230 Z - 4,140,409.453 (meters)
  COMP
• LP0230 LAPLACE CORR- 2.08 (seconds)
  DEFLEC99
• LP0230 ELLIP HEIGHT- 1278.524 (meters)
  (02/10/07) ADJUSTED

25
NGS Datasheet Leveling/GPS

• LP0230 VERT ORDER - FIRST CLASS I
• LP0230
• LP0230.The horizontal coordinates were
  established by GPS observations
• LP0230.and adjusted by the National Geodetic
  Survey in February 2007.
• LP0230
• LP0230.The datum tag of NAD 83(2007) is
  equivalent to NAD 83(NSRS2007).
• LP0230.See National Readjustment for more
  information.
• LP0230.The horizontal coordinates are valid at
  the epoch date displayed above.
• LP0230.The epoch date for horizontal control is
  a decimal equivalence
• LP0230.of Year/Month/Day.
• LP0230
• LP0230.The orthometric height was determined by
  differential leveling
• LP0230.and adjusted in June 1991.
• LP0230
• LP0230.The X, Y, and Z were computed from the
  position and the ellipsoidal ht.
• LP0230
• LP0230.The Laplace correction was computed from
  DEFLEC99 derived deflections.
• LP0230
• LP0230.The ellipsoidal height was determined by
  GPS observations

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NGS Datasheet Leveling/GPS

• LP0230.The modeled gravity was interpolated from
  observed gravity values.
• LP0230
• LP0230 North East
  Units Scale Factor Converg.
• LP0230SPC UT C - 2,266,073.850
  443,127.505 MT 1.00002033 -0 25 52.5
• LP0230UTM 12 - 4,509,219.421
  400,926.638 MT 0.99972081 -0 45 55.9
• LP0230
• LP0230! - Elev Factor x Scale
  Factor Combined Factor
• LP0230!SPC UT C - 0.99979948 x
  1.00002033 0.99981981
• LP0230!UTM 12 - 0.99979948 x
  0.99972081 0.99952035
• LP0230
• LP0230 SUPERSEDED
  SURVEY CONTROL
• LP0230
• LP0230 NAD 83(1994)- 40 43 40.61672(N) 112
  10 23.51198(W) AD( ) A
• LP0230 ELLIP H (06/28/00) 1278.548 (m)
  GP( ) 4 1
• LP0230 NAVD 88 (06/28/00) 1295.73 (m)
  4251.1 (f) LEVELING 3
• LP0230 NGVD 29 (??/??/92) 1294.74 (m)
  4247.8 (f) COMPUTED 1 1
• LP0230
• LP0230.Superseded values are not recommended for
  survey control.
• LP0230.NGS no longer adjusts projects to the NAD
  27 or NGVD 29 datums.

27
NGS Datasheet NAVD 88 GPS

• 1 National Geodetic Survey, Retrieval
  Date JANUARY 26, 2009
• DF4644
  
• DF4644 DESIGNATION - SLCP BASE STATION
• DF4644 PID - DF4644
• DF4644 STATE/COUNTY- UT/SALT LAKE
• DF4644 USGS QUAD - SALT LAKE CITY SOUTH
  (1975)
• DF4644
• DF4644 CURRENT SURVEY
  CONTROL
• DF4644 _________________________________________
  __________________________
• DF4644 NAD 83(2007)- 40 44 11.46882(N) 111
  53 40.49145(W) ADJUSTED
• DF4644 NAVD 88 - 1301.3 (meters)
  4269. (feet) GPS OBS
• DF4644 _________________________________________
  __________________________
• DF4644 EPOCH DATE - 2002.00
• DF4644 LAPLACE CORR- 9.53 (seconds)
  DEFLEC99
• DF4644 ELLIP HEIGHT- 1284.363 (meters)
  (02/10/07) ADJUSTED
• DF4644 GEOID HEIGHT- -16.84 (meters)
  GEOID03
• DF4644
• DF4644 ------- Accuracy Estimates (at 95
  Confidence Level in cm) --------

28
Height Mod GPS Datasheet

• 1 National Geodetic Survey, Retrieval
  Date JANUARY 4, 2008
• DH5603
  
• DH5603 HT_MOD - This is a Height
  Modernization Survey Station.
• DH5603 DESIGNATION - ALTO S GPS
• DH5603 PID - DH5603
• DH5603 STATE/COUNTY- WI/FOND DU LAC
• DH5603 USGS QUAD - BRANDON (1980)
• DH5603
• DH5603 CURRENT SURVEY
  CONTROL
• DH5603 _________________________________________
  __________________________
• DH5603 NAD 83(2007)- 43 38 45.90850(N) 088
  49 31.20449(W) ADJUSTED
• DH5603 NAVD 88 - 283.45 (meters)
  930.0 (feet) GPS OBS
• DH5603 _________________________________________
  __________________________
• DH5603 EPOCH DATE - 2002.00
• DH5603 X - 94,770.713 (meters)
  COMP
• DH5603 Y - -4,621,912.764 (meters)
  COMP
• DH5603 Z - 4,379,891.970 (meters)
  COMP
• DH5603
• DH5603

29
NGS Datasheet Leveling/GPS

• 1 National Geodetic Survey, Retrieval
  Date JANUARY 26, 2009
• LP0230
  
• LP0230 CBN - This is a Cooperative
  Base Network Control Station.
• LP0230 DESIGNATION - E 174
• LP0230 PID - LP0230
• LP0230 STATE/COUNTY- UT/SALT LAKE
• LP0230 USGS QUAD - FARNSWORTH PEAK (1972)
• LP0230
• LP0230 CURRENT SURVEY
  CONTROL
• LP0230 _________________________________________
  __________________________
• LP0230 NAD 83(2007)- 40 43 40.61719(N) 112
  10 23.51247(W) ADJUSTED
• LP0230 NAVD 88 - 1295.727 (meters)
  4251.06 (feet) ADJUSTED
• LP0230 _________________________________________
  __________________________
• LP0230 EPOCH DATE - 2002.00
• LP0230 X - -1,827,153.513 (meters)
  COMP
• LP0230 Y - -4,483,296.800 (meters)
  COMP
• LP0230 Z - 4,140,409.453 (meters)
  COMP
• LP0230 LAPLACE CORR- 2.08 (seconds)
  DEFLEC99
• LP0230 ELLIP HEIGHT- 1278.524 (meters)
  (02/10/07) ADJUSTED

H h - N 1295.727
1278.524 - (- 17.19) 1295.727 ? 1295.714
(0.013 m/0.04) ft)
30
To use GNSS you need a good geoid model

• NGS makes 2 geoid models
• Gravitational model
• is good for scientific applications
• uses gravity data collected from a variety of
  sources
• Hybrid model
• starts with gravitational model
• uses GPS on bench marks to enable a fit to NAVD88

GRACE Satellite Gravity
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• GGPSBM1999 6,169 total 0 Canada STDEV
  9.2 cm (2s)

• GGPSBM2003 14,185 total 579 Canada STDEV 4.8
  cm (2s)

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• Is the current approach
• the best approach?

33
Goals of HMP

• Access to accurate, reliable heights nationally
• Standards that are consistent across the nation
• Data, technology, and tools that yield consistent
  results regardless of terrain and circumstances
• A system/process that will stand the test of time
  Maintain-able

34
Consistency?
Funding
GPS on BMs
Gravity
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National Height Modernization Program
36
A National Program - Pros

• Needs dont stop at state boundaries
• States within a region work in concert to support
  common issues/goals
• More efficient use of funds, people
• Encourages partnerships
• Congress more likely to continue funding for
  programs that impact a larger area/group of
  constituents commitment to program on part of
  users

37
A National Program - Cons

• Political realities
• Organizational structure
• Organizational mandates/missions
• Travel/work between states
• Problems sharing funds, people

How can states work together?
38
NOAA Regions
39
Why isnt NAVD 88 good enough anymore?

• NAVD88 defined through leveling network
• Leveling the country can not be done again
• At 3000 / km, re-leveling NAVD 88 would cost
  2.25 Billion
• Does not include densifying poorly covered areas
  in Western CONUS, Alaska
• Does not include leveling needed for separate
  vertical datums on island states and territories
• Leveling yields cross-country error build-up
  problems in the mountains
• Leveling requires leaving behind marks
• Bulldozers and crustal motion do their worst

Maintain-able?
40
Why isnt NAVD 88 good enough anymore?

• The GPS era brought fast, accurate ellipsoid
  heights naturally this drove a desire for fast,
  accurate orthometric heights
• If the geoid were determined to highest accuracy
  GNSS will yield fast, accurate orthometric
  heights
• Data from satellite gravity projects, GRACE and
  GOCE, can be used to control the continental
  error in the geoid

41
The National Geodetic Survey 10 year plan --
Mission, Vision and Strategy 2008-2018

• Official NGS policy as of Jan 9, 2008
• Mission Focused
• Modernized Agency
• Attention to accuracy
• Attention to time-changes
• Improved products and services
• Integration with other fed missions
• www.ngs.noaa.gov/10yearplan
• 2018 Targets
• NAD 83 and NAVD 88 replaced
• Cm-accuracy access to all coordinates
• Customer-focused agency
• Global scientific leadership

42
From the 10 year plan

• The NSRS must be more accurate than all
  activities which build upon it, while still being
  practically achievable
• You cant get orthometric height accuracy of a
  centimeter, when the vertical datum has a half
  meter bias and one meter tilt across the country.
• You cant have mm/year accuracy in absolute sea
  level rise when the NSRS is built on an ITRF
  accuracy of cm/year
• The era of using geodetic leveling for
  continent-scale vertical datum definition comes
  to an end.

43
Transition to the Future GRAV-D
Gravity for the Redefinition of the American
Vertical Datum

• Dan Roman
• Geoid modeling
• Vicki Childers
• GRAV-D

44
GRAV-D is the most ambitious project within the
National Height Mod Program

• National Height Modernization needs to support
  the NAVD 88 while transitioning (via GRAV-D) to a
  new vertical datum in 10 years
• All National Height Mod funds (internal or
  grants) should support access to accurate
  heights, in general, but
• With emphasis on NAVD 88 today
• With emphasis on the new vertical datum in 5
  years

45
From the 10 year plan

• The culmination of all these efforts GRAV-D
  allows fast, accurate determination of heights
  through GPS, and thus truly represents Height
  Modernization as originally envisioned..
• A geoid model computed for all USA lands at 1 cm
  accuracy wherever possible, and tracked in time
  to that accuracy to yield 2 cm orthometric
  heights
• Time tracking will require local help for
  smallest signals, including gravity surveys and
  GPS/leveling co-located minimally constrained
  surveys

46
NOAAs Roles and Responsibilities
Program Management Grants Process Outreach/Technol
ogy Transfer Program Leadership Quality
Assurance/Control Research and Development
Models and Tools - Gravity/geoid model -
V-Datum
47
HM Partners are Crucial to NOAAs Height
Modernization Efforts

• Local Infrastructure/ CORS/State Geodetic Surveys
• State Geodetic Liaison
• Spatial Reference Centers
• Education/outreach/ technology transfer
• State and local partnerships

48
NGS Business Plan Three Areas of Focus

• Infrastructure
• Models and Tools
• Outside Capacity Building

49
Infrastructure

• Define, maintain, provide access to NSRS
• Active control network CORS
• Passive control network as needed
• Guidelines and standards for geodetic field and
  processing practices
• Quality check data that is incorporated in the
  NGS database
• Enable positioning consistent with NSRS

50
MTSU, Bozeman, MT
CORS
RBUT, Salt Lake City, UT
EGAN, Ely, NV
AZSC, Scottsdale, AZ
51
This is a
white on white text box for the purpose of
masking a picture

HARN (Utah 2002)
52
Published Height Modernization Stations
53
Models and Tools

• Modeling atmospheric, 1-cm geoid
• Development of software, tools
• Software, Online Tool Kit
• OPUS Variety Pack
• Field tools PGM, Digital Level Tool
• VERTCON, VDatum
• Guidelines for use of new technologies and
  processes like remote sensing, real time

54
Guidelines
Level Tool under development at TAMUCC
www.ngs.noaa.gov/PUBS_LIB/pub_index.html
55
Outside Capacity Building

• State Geodetic Advisor Program
• Forums, workshops
• Conferences
• Publications, web site
• Training, capacity building

56
Leveling Spokane, 2006
www.ngs.noaa.gov/heightmod
Training center, Corbin, VA
www.ngs.noaa.gov/corbin/index.shtml
57
HM in Practice What States are doing now

• Infrastructure establish, densify, maintain
• CORS
• Passive control - leveling
• Co-locate CORS and tide stations level to tide
  stations
• Surveys
• Remote sensing
• Pilot projects, test guidelines
• Collect, distribute data
• Gravity collection?

58
HM in Practice What States are doing now

• Models, tools
• Build state GIS
• Develop software PGM, THM level tool
• Outreach, education
• Create Spatial Reference Centers
• Workshops, forums
• Websites, data access
• Partnerships
• With FEMA NC and MT are Cooperative Technical
  States
• Other states within their region

59
National Height Modernization supporting the
10 year plan

• National Height Modernization funds will
• Maintain NAVD 88 until it is replaced
• Build new CORS
• Survey the gravity field
• Create a transformation tool for the new datum
• Perform gravity monitoring surveys
• Perform geoid slope monitoring surveys
• Educate users
• Build online tools

60
Conclusion

• National Height Modernization is a good idea
• Equitable accuracy and access for all states
• Represents a transition from NAVD 88 to a new
  vertical datum
• Maintain the old, prepare the new, pay for both
  during the transition
• The goal of GRAV-D, a new GNSS-accessible
  vertical datum, is the essence of Height
  Modernization

61
Speaker Bios

• RENEE SHIELDS
• HEIGHT MODERNIZATION MANAGER
• NATIONAL GEODETIC SURVEY, NOS, NOAA
•  
• Ms. Shields is a geodesist in the Geodetic
  Services Division of the National Geodetic Survey
  (NGS). She received a bachelors degree in
  Mathematics from the University of
  Massachusetts/Boston in 1976. Ms. Shields has
  been with NGS since 1980, and has experienced
  major involvement in the geodetic adjustments for
  the North American Datum of 1983, and integration
  of new Global Positioning System (GPS) projects
  into the National Spatial Reference System
  (NSRS). This included assisting in the
  development of the constrained adjustment
  guidelines, primary responsibility for the High
  Accuracy Reference Networks adjustments, and the
  state-wide readjustment of several states. She
  has extensive experience in GPS and Geoid Height
  analysis, and has successfully used this
  experience to develop and conduct workshops
  around the country on incorporation of data into
  the NSRS. Renee is currently Project Manager for
  the Height Modernization Program, an effort that
  has 17 states as regular participants and
  additional activities in a number of other
  states. She coordinates and manages the program,
  through outreach activities, education, and
  development of policies and guidelines, with the
  goal of establishing nationwide implementation of
  Height Modernization.

62
Speaker Bios

• Dan Roman, PhD
• Geoid Model Team
• Dan Roman has been with the National Geodetic
  Survey (NGS) since 1999. Dr. Roman has led
  theoretical and practical aspects of geodetic
  research in the NGS Geosciences Research Division
  for the past nine years. His research efforts
  have led to the development of the GRAV-D project
  and a potentially significant change in the U.S.
  vertical datum.
• Vicki Childers, PhD
• GRAV-D Project Manager
• Dr. Vicki Childers earned a Ph.D. in airborne
  geophysics from Columbia University.  She worked
  for 12 years with the Naval Research Lab on
  airborne geophysics, geodesy, and oceanography
  studies. Dr. Childers joined NGS in May, 2008 to
  manage the GRAV-D Project.

63
Questions
Renee Shields Height Modernization
Manager 301-713-3231, x116 Renee.Shields_at_noaa.gov
Dan Roman Geoid Modeling Team Lead 301-713-3202,
x161 Dan.Roman_at_noaa.gov
Vicki Childers GRAV-D Program Manager 301-713-3211
, x161 Vicki.Childers_at_noaa.gov
http//www.ngs.noaa.gov/heightmod/EventsArchive.sh
tml