Louisiana State University Activities at the Louisiana Spatial

Louisiana State University Activities at the Louisiana Spatial Reference Center Roy K. Dokka, Ph. D. Center for Geo. Informatics and Louisiana Spatial Reference Center Louisiana State University, Baton Rouge, LA 70803 2009 Height Modernization Meeting Beaumont, TX

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

Louisiana State University A system of accurate elevations has been near impossible to maintain in along the Gul Coast. Why? • Subsidence. • 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”. • No Leadership or $$

What is the overall strategy regarding 3 -D positioning in LA? Louisiana State University n n 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: n n n Maintaining a basic backbone of about a few hundred benchmarks in south Louisiana, Supporting CORS, Providing a geoid model, Development of technical standards. LSU will provide state-wide GNSS technology to facilitate accurate and precise “anywhere-any time” 3 -D positioning.

Louisiana State University n 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: 1. 2. 3. 4. Maintain traditional vertical control. Real-time 3 -D positioning. Hybrid of 1 and 2. Do nothing.

Louisiana State University LSU’s Role in Fixing the Problem “Positioning Louisiana for the future” Operation of GULFNet GPS Reference Network across South Louisiana n 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 reobservations. Heights recognized as legal under Louisiana State law. www. ngs. noaa/CORS Creation of a State-wide Real-time Network n 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 2004. 65 elevations by site calibration. n Outreach Develop and provide know-how to enable users to exploit the new resources.

Louisiana State University

Distance to a CORS Louisiana State University

Louisiana State University Time on a Mark

Louisiana State University How does single base RTK work?

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

Louisiana State University How does GULFNet RTN work?

RTN Real-Time Network Based on VRS technology Louisiana State University “Positioning anywhere, any time” Relative vertical: + 2 cm (3 min. ) Kinematic mode: + 0. 3 ft (1 sec. ) Cellular device to connect user to Internet and LSU GULFNet RTN Native output in “CORS 2002” but can easily be put in 2004. 65 context through calibration.

Louisiana State University Height Matters! Especially in Louisiana

The Louisiana Legislature requested LSU measure the height of the South LA HPS in 2006 -2007. N = 50, 000 points Louisiana State University Note: Does not reflect post 2007 changes Due to construction by USACE

Louisiana State University FEMA mapping partners need to use real weir elevations in ADCIRC models

Louisiana State University Operational NHC Katrina SLOSH model using outdated or assumed elevation data 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. Katrina SLOSH using accurate topography

Louisiana State University How about FEMA flood maps in Southeast Texas

Louisiana State University US 90 I-10 at US 90 FEMA (green) Gulfnet RTM (black)

Louisiana State University Summary of Activities at LSRC “Positioning Louisiana for the future” Operation of GULFNet GPS Reference Network across South Louisiana n 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 reobservations. Heights recognized as legal under Louisiana State law. www. ngs. noaa/CORS Creation of a State-wide Real-time Network n 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 2004. 65 elevations by site calibration. n Outreach Provide know-how to enable users to exploit the new resources.

Louisiana State University Thank You!