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Activities at the Louisiana Spatial Reference Center Roy K. Dokka, Ph.D. Center for GeoInformatics and Louisiana Spatial Reference Center Louisiana State.

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Presentation on theme: "Activities at the Louisiana Spatial Reference Center Roy K. Dokka, Ph.D. Center for GeoInformatics and Louisiana Spatial Reference Center Louisiana State."— Presentation transcript:

1 Activities at the Louisiana Spatial Reference Center Roy K. Dokka, Ph.D. Center for GeoInformatics and Louisiana Spatial Reference Center Louisiana State University, Baton Rouge, LA LouisianaStateUniversity 2009 Height Modernization Meeting Beaumont, TX

2 LouisianaStateUniversity NOAA told the U.S. Congress in 2001 that the system used to measure elevations in LA was, Gulf Coast: A vulnerable landscape with a constantly changing landscape “inaccurate and obsolete and unable to support public safety.” Bad vertical control affects levees, planning, evacuation roads, FEMA flood maps, and LiDAR.

3 LouisianaStateUniversity A system of accurate elevations has been near impossible to maintain in along the Gulf Coast. Why? Subsidence. Subsidence. A lack of understanding of how and why subsidence occurs. A lack of understanding of how and why subsidence occurs. A willingness to accept “the best available data” instead of “accurate and sufficiently precise data to meet requirements and the standard of care”. A willingness to accept “the best available data” instead of “accurate and sufficiently precise data to meet requirements and the standard of care”. No Leadership or $$No Leadership or $$

4 LouisianaStateUniversity What is the overall strategy regarding 3-D positioning in LA? The ability to obtain accurate elevations has always been a shared responsibility between NGS, local government, surveyors, and others. The ability to obtain accurate elevations has always been a shared responsibility between NGS, local government, surveyors, and others. NGS is committed to providing users in LA with access to the NSRS. This means: NGS is committed to providing users in LA with access to the NSRS. This means: Maintaining a basic backbone of about a few hundred benchmarks in south Louisiana, Maintaining a basic backbone of about a few hundred benchmarks in south Louisiana, Supporting CORS, Supporting CORS, Providing a geoid model, Providing a geoid model, Development of technical standards. Development of technical standards. LSU will provide state-wide GNSS technology to facilitate accurate and precise “anywhere-any time” 3-D positioning. LSU will provide state-wide GNSS technology to facilitate accurate and precise “anywhere-any time” 3-D positioning.

5 LouisianaStateUniversity Bottomline? Local people and governments will have to decide how they wish to access the NSRS. You will have to pay for it and live with the consequences. Your choices are: Local people and governments will have to decide how they wish to access the NSRS. You will have to pay for it and live with the consequences. Your choices are: 1. Maintain traditional vertical control. 2. Real-time 3-D positioning. 3. Hybrid of 1 and Do nothing.

6 LouisianaStateUniversity LSU’s Role in Fixing the Problem Operation of GULFNet GPS Reference Network across South Louisiana Operation of GULFNet GPS Reference Network across South Louisiana CORS. Users can access the National Spatial Reference System anywhere in Louisiana with confidence. Think of CORS as “smart benchmarks”. GULFNet is updated daily and will remain accurate into the future without costly re- observations. Heights recognized as legal under Louisiana State law. CORS. Users can access the National Spatial Reference System anywhere in Louisiana with confidence. Think of CORS as “smart benchmarks”. GULFNet is updated daily and will remain accurate into the future without costly re- observations. Heights recognized as legal under Louisiana State law. Creation of a State-wide Real-time Network Creation of a State-wide Real-time Network GULFNet real-time kinematic GPS RTN network allows users to obtain accurate and precise 3-D positions anywhere-anytime in Louisiana. Precision: 1 cm Horiz., 2 cm Vert. Users can obtain elevations by site calibration. GULFNet real-time kinematic GPS RTN network allows users to obtain accurate and precise 3-D positions anywhere-anytime in Louisiana. Precision: 1 cm Horiz., 2 cm Vert. Users can obtain elevations by site calibration. Outreach Outreach Develop and provide know-how to enable users to exploit the new resources. “Positioning Louisiana for the future”

7 LouisianaStateUniversity

8 LouisianaStateUniversity Distance to a CORS

9 LouisianaStateUniversity Time on a Mark

10 LouisianaStateUniversity How does single base RTK work?

11 LouisianaStateUniversity Conventional Single Base RTK Rover linked to base via radio Need a base a radio, Need a base a radio, and a rover. $$$ and a rover. $$$ Added time for Added time for base set-up base set-up & processing & processing of base(s). of base(s). Time intensive compared Time intensive compared to RTN. to RTN. Errors accumulate at Errors accumulate at 1ppm away from base. 1ppm away from base.

12 LouisianaStateUniversity How does GULFNet RTN work?

13 LouisianaStateUniversity RTN Real-Time Network Based on VRS technology “Positioning anywhere, any time” Cellular device to connect user to Internet and LSU GULFNet RTN Kinematic mode: ft (1 sec.) Relative vertical: + 2 cm (3 min.) Native output in “CORS 2002” but can easily be put in context through calibration.

14 LouisianaStateUniversity Height Matters! Especially in Louisiana

15 LouisianaStateUniversity The Louisiana Legislature requested LSU measure the height of the South LA HPS in N = 50,000 points Note: Does not reflect post 2007 changes Due to construction by USACE

16 LouisianaStateUniversity FEMA mapping partners need to use real weir elevations in ADCIRC models

17 LouisianaStateUniversity Operational NHC Katrina SLOSH model using outdated or assumed elevation data Katrina SLOSH using accurate topography Note: The so-called “funnel” is a modeling artifact caused by the use of authorizied elevations instead of valid measurements along south levee of MRGO.

18 LouisianaStateUniversity How about FEMA flood maps in Southeast Texas

19 LouisianaStateUniversity I-10 at US 90 FEMA (green) Gulfnet RTM (black) Gulfnet RTM (black) US 90

20 LouisianaStateUniversity Summary of Activities at LSRC Operation of GULFNet GPS Reference Network across South Louisiana Operation of GULFNet GPS Reference Network across South Louisiana 50 CORS. Users can access the National Spatial Reference System anywhere in Louisiana with confidence. Think of CORS as “smart benchmarks”. GULFNet is updated daily and will remain accurate into the future without costly re- observations. Heights recognized as legal under Louisiana State law. 50 CORS. Users can access the National Spatial Reference System anywhere in Louisiana with confidence. Think of CORS as “smart benchmarks”. GULFNet is updated daily and will remain accurate into the future without costly re- observations. Heights recognized as legal under Louisiana State law. Creation of a State-wide Real-time Network Creation of a State-wide Real-time Network GULFNet real-time kinematic GPS RTN network allows users to obtain accurate and precise 3-D positions anywhere-anytime in Louisiana. Precision: 1 cm Horiz., 2 cm Vert. Users can obtain elevations by site calibration. GULFNet real-time kinematic GPS RTN network allows users to obtain accurate and precise 3-D positions anywhere-anytime in Louisiana. Precision: 1 cm Horiz., 2 cm Vert. Users can obtain elevations by site calibration. Outreach Outreach Provide know-how to enable users to exploit the new resources. “Positioning Louisiana for the future”

21 LouisianaStateUniversity Thank You!


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