Pennsylvania HM Forum

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NOAA
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National Geodetic Survey
Gilbert Mitchell, Chief, Geodetic Services
Division Juliana Blackwell, Height Modernization
Program Manager
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National Geodetic SurveyPriorities
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NSRS Adjustment
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Coastal Mapping
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Specifications, Guidelines, and Tools
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FAA QA/QC
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CORS Enhancement
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Height Modernization and Leveling
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Height Modernization
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Height Modernization
San Francisco Bay Demonstration Project
GPS Buoy Monitoring Water Levels
U.S Coast Guard Buoy Tender Cm-Level Positioning
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Height Modernization

• Background What? Why?
• Heights How?
• Needs and Benefits Where?
• Outreach Who? When?

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Height Modernization

• Background

WHAT?
WHY?
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Height Modernization
Definition the establishment of accurate,
reliable heights using GPS technology in
conjunction with traditional leveling, gravity,
and modern remote sensing information.
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Height Modernization
Height Modernization
Objective
NAVD 88

NSRS

Geodetic Control
National Vertical Datum accessed through the NSRS
Infrastructure that is

• Reliable
• Cost-effective
• Standardized
• Legally Established

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(No Transcript)
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Height Modernization Background
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Height Modernization Appropriations
Height Modernization
Fiscal Year Appropriations States
FY 2001 2.25 M CA, NC
FY 2002 3.75 M CA, NC, LA, WI
FY 2003 3.75 M CA, NC, LA, WI, MS
FY 2004 9.0 M CA, NC, LA, WI, MS, AL, WA, SC
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Why Height Modernization?
Height Modernization
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Height Modernization
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Navigation / Ports
Height Modernization
Determination of the Real Rate of Sea Level Rise
Precise Positioning of Dredges and Dredge
Materials
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Agriculture / Aquaculture
Height Modernization
Real-Time Positioning of Farm Equipment and
Reduced Production Costs
More Efficient Fish Farming including Crawfish
Farming
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Land Information System
Height Modernization
Provides Greater Accuracy for Field Checks on
Digital Orthophotos
Provides Field Reference Points for Verifying
Accuracy of Resource Grade GPS Collected Data
Improves Data Quality for More Detailed Terrain
Modeling and 3-D Visualization
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Land Survey
Provides More Accurate Horizontal and Vertical
Geodetic Control
Remote Sensing and Shoreline Mapping Support
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Monitoring and Mapping Coastal Erosion
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Monitoring Hurricane Damage
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Measuring Heights Along Evacuation Routes
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Height Modernization Measuring Subsidence
Harris-Galveston, Texas Coastal Subsidence
District
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GPS Heights Guidelines
Available On-Line at the NGS Web
Site www.ngs.noaa.gov
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GPS-derived Orthometric Heights

• Occupy stations with known NAVD 88 orthometric
  heights
• Stations should be evenly distributed throughout
  project
• Project areas less than 20 km on a side, surround
  project with NAVD 88 bench marks
• i.e., minimum number of stations is four one in
  each corner of project
• Project areas greater than 20 km on a side, keep
  distances between GPS-occupied NAVD 88 bench
  marks to less than 20 km
• Projects located in mountainous regions, occupy
  bench marks at base and summit of mountains, even
  if distance is less than 20 km

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Height Modernization
Height Modernization

• Heights

HOW?
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Height Modernization
Height Modernization
How to achieve accurate GPS heights

• (1) What types of heights are involved?
• Ellipsoid heights (GPS)
• Geoid heights (model)
• Orthometric heights (leveling)
• (2) How are these heights defined and related?
• (3) How accurately can these heights be
  determined?

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Ellipsoid, Geoid, and Orthometric Heights
Earths
H h - N
Surface
P
Plumb Line
Ellipsoid
h
H
Q
N
Mean
Sea
Geoid
Level
PO
Ocean
h (Ellipsoid Height) Distance along ellipsoid
normal (Q to P)
N (Geoid Height) Distance along ellipsoid
normal (Q to PO)
H (Orthometric Height) Distance along plumb
line (PO to P)
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Project Layout
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Conventional Leveling
ROD 1
BM 100
INSTR
BM
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GEOID03 -- the link between GPS heights and
leveling
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GEOID03
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Improved GPS-derived heights require

• Improved ellipsoid heights
• Better field procedures
• Accurate ellipsoid heights at control stations
• An improved geoid
• Accurate ellipsoid heights
• More benchmarks with GPS measurements
• Accurate orthometric heights at benchmarks

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• Needs and Benefits

WHERE?
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California Spatial Reference Center
Master Plan for a spatial reference network for
height modernization and geodetic control in
California

• Includes a mix of CORS and traditional monuments
  along transportation corridors
• Implementation dependent on technological
  developments (wide-area RTK, real-time networks,
  and wireless communications)
• A complete data set of NAVD88
• heights will be computed for the
• California CORS network.

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North Carolina Height Modernization
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HEIGHT Modernization Supports MAP Modernization

• Height Modernization control for floodplain maps
  and LIDAR surveys
• OPUS for floodplain certificates and LIDAR
  surveys
• Subsidence rates, maps, and tools for floodplain
  managers
• Guidelines for use of GPS and LIDAR for
  floodplain mapping

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Louisiana Spatial Reference Center
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Wisconsin Height Modernization Plan
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Height Modernization Benefits
RTK GPS - Wisconsin DOT

• Establish horizontal and vertical coordinates for
  design surveys.
• 40 50 less time.
• Less time needed for error analysis between GPS
  and Leveling derived elevations.
• All positions are easily re-established.
• Reduced the need for any conventional leveling.
• Instant coordinates.

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RTK GPS - Wisconsin DOT

• Collect Horizontal and Vertical positions for
  construction surveys.
• Require less engineering (project) control.
• Faster to provide and reproduce engineering
  control that is needed/requested.
• Reduce the need for conventional leveling.
• All positions are easily re-established.
• Control is off of the job site.

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• Outreach

WHEN?
WHO?
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NGS Role and Responsibilities

• Program Management -- Congressional briefings,
  budget, grants management, coordination, outreach
• Outreach/Technology Transfer -- advisors, forums,
  workshops, conferences, publications, training,
  outsourcing
• Project Leadership -- project planning,
  specifications, guidelines, CORS management
• Quality Control -- training, assess techniques,
  survey control, load projects into NGS database
• Research and Development software development,
  remote sensing, modeling, investigate GPS
  techniques, antenna calibrations

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Partnerships

• Federal
• State
• Parishes

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Height Modernization Partnerships
Spatial Reference Centers
California, Louisiana, Washington Harris-Galveston
Subsidence District State Agencies
SCGS, NCGS, WiDOT,
ALDOR, WADNR Universities
University of Southern
Mississippi North
Carolina AT State University
Louisiana State
University University of California/Scripps
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FEMA

• Flood Insurance Risk Maps
• Determining High Water Marks
• Elevation Certificates
• Dam Safety
• Mitigation

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Advisor Program
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Outreach Forums Workshops
July 16 Forum in Harrisburg, PA July 22
Meeting in Tallahassee, FL August 17-19
Geospatial Conference, San Antonio, TX September
12-16 3 Forums in Washington State September
23-24 Workshop in Greensboro, NC October 25
Forum in Somerset, KY
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Questions?