Louisiana State University’s Center for GeoInformatics (C4G) in its role as the Louisiana Spatial Reference Center (LSRC) has been awarded a grant for $3.1 million over the next five years (2018-2023) from the National Oceanic and Atmospheric Administration (NOAA) for their support in the Regional Geospatial Modeling. The Principal Investigator and Project Director is Boyd Professor George Z. Voyiadjis, Director of the C4G with Co-Investigators Randy L. Osborne, Clifford J. Mugnier and J. Anthony Cavell. Larry Dunaway and Jon Cliburn round out the investigating team.

$400K Micro-g LaCoste FG5-X Absolute Gravity Meter
Setup of C4G’s new $400K Micro-g LaCoste FG5-X Absolute Gravity Meter on the Baton Rouge – AA gravity mark in the CEE Materials Lab located in Patrick F. Taylor Hall.

The LSRC’s grant awarded in collaboration with a continuing 5-year Gulf Coast-wide partnership among Mississippi, Texas, Louisiana, Florida and Alabama; is to support the improvement and modernization of NOAA’s National Spatial Reference System (NSRS). Key to these efforts will be the collection of accurate, precise, and consistent geospatial data to improve regional geospatial models and to coordinate the use of this geospatial data by users to improve the NSRS for the states bordering the northern Gulf of Mexico. Partnership outreach efforts will bring awareness, access, and education to users of the NSRS. The geospatial data resources produced through the partnerships will improve NSRS Height Modernization efforts across the entire northern Gulf of Mexico coast.

The LSRC at Louisiana State University proposed a unified, regional partnership that will focus on the following objectives as the Louisiana portion of the broader proposal package submitted by the University of Southern Mississippi.

C4G staff participated in the 2018 NACAG at Table Mountain
C4G staff Jon Cliburn & Larry Dunaway participated in the 2018 North American Comparison of Absolute Gravimeters event heald at NOAA’s Table Mountain Gravity Observatory in Longmont, CO.

LSRC will work to enhance the infrastructure of geodetic control, coastal remote sensing data, terrestrial gravity measurements and other physical datasets. Various means will be used which include deploying two Scintrex CG-5 Relative Gravity Meters that were purchased at a cost of $100K each under prior grants, one from a NOAA/NGS height modernization grant and another from an LSU Board of Regents grant. C4G’s new self-funded $400K Micro-g LaCoste FG5-X Absolute Gravity Meter will be deployed to collect terrestrial gravity measurements at the C4G’s Continuously Operating Reference Stations (CORS), NSRS benchmarks, and LSRC eccentric benchmarks, which will allow LSRC to improve the geodetic modeling for future datums and NSRS modernization.

Several newly acquired pieces of equipment will be used for these observations. The Scintrex Trident Tripod, which in conjunction with C4G’s CG-5 Relative Gravity Meters will be used to observe the Gravity Gradient by accurately positioning the gravity meter at three predetermined levels for quick and precise measurements. The LSRC will acquire through the NOAA grant a $100K Digital Zenith camera in the first year of this grant from the Institute of Geodesy and Geoinformatics located at the University of Latvia and use this new instrument to measure the vertical deflection at CORS sites. The deflection of the vertical is a measure of how far the gravity direction has shifted, caused by local anomalies, which helps increase the accuracy of local surveys of the Earth’s gravity field.

Typical InSAR image taken of the Greater New Orleans area.
Typical InSAR image taken of the Greater New Orleans area.

LSRC will also collaborate with NASA’s Jet Propulsion Lab (JPL) in order to investigate targeting methods using InSAR to track regional subsidence to help develop guidelines and tools to access geodetic control and to manipulate and analyze geodetic data.

LSRC continues to maintain its existing geospatial data clearinghouse it established to provide free access to information that includes CORS raw data, flood maps, satellite, and aerial photography, digital elevation models (e.g., LiDAR, RADAR, and InSAR), and other relevant assets necessary for regional geospatial modeling.

The national goal is to develop models with accuracies better than 2 cm (3/4 in.). The dynamic nature of Louisiana’s geology makes it an outlier when continental geodetic models are developed, with many negative results for Louisiana. The LSU C4G has demonstrated the ability to observe precise terrestrial gravity, elevations and geometric relationships to the degree necessary for improving the geodetic models. Observing and possibly predicting subsidence in south Louisiana and along the Gulf Coast has been an acute challenge recognized since the 1950s, and becomes more acute with time. The NOAA grant seeks to build on the work of the LSU C4G that shows promise of bringing Louisiana, and the Gulf Coast into the norm, permitting accurate geoid models, flood mapping, coastal studies, levee construction and public safety in general.

NGS plot shows GEOID12a produces 95% confidence at ± 4 to 8 cm in Louisiana
NGS plot shows GEOID12a produces 95% confidence at ± 4 to 8 cm in Louisiana

The Center for GeoInformatics was created in 2001 to build new research and services in Geodesy and Geoinformatics for the geodetic and geophysical communities. The C4G, in cooperation with NOAA’s National Geodetic Survey (NGS), founded the Louisiana Spatial Reference Center in 2002 as a partnership focused on a state-of-the-art positional infrastructure for the state of Louisiana and to provide technical leadership, training and access to positional data. LSRC is responsible for the network of GNSS control stations; a reliable spatial reference system in Louisiana (GULFnet). The C4G maintains the GNSS Real Time Network (C4Gnet), established in 2007 to serve surveying, mapping, utilities, emergency response, agriculture, forestry, public safety, transportation, machine control for construction, environmental, and scientific research. – Positioning Louisiana for the Future.


Welcome to the LSU Center for GeoInformatics (C4G)
Home of the Louisiana Spatial Reference Center (LSRC) and the 
GULFNet Continuously Operating Reference Station (CORS) Network

Access to all GULFNet CORS data in the repository are made available freely
to the public through the LSU C4G in its role of LSRC and partnerships with
members of the Gulf Coast Spatial Reference Consortium (GCSRC).
Data can be retrieved using command line or FTP client via anonymous ftp from CORS.lsu.edu on port: 8021 or by pointing your browser to ftp://cors.lsu.edu:8021/ (due to increases in security efforts not all
browsers support direct access using the FTP protocol) GULFNet CORS stations are owned and operated by C4G or our partners in the GCSRC - Gulf Coast Spatial Reference Consortium. GULFNet CORS data are distributed to the public free of charge. All LSRC CORS GNSS data files collected from GULFNet CORS stations are made available to NGS & the public in Trimble’s proprietary data-file formats (R00/T00/T01/T02) or (.DAT or .TGD). All GULFNet CORS files found in this
data archive are logged in formats by native to Trimble GPS/GNSS receivers
from "Record Type 27" (RT27) files. The data include observation,
meteorological, navigation/ephemeris for the stations. Most data are
available within 1 hour from when they were recorded at remote CORS sites.
Louisiana NGS CORS
======================== NGS redistributes some of the GULFNet CORS data to the public free of
charge through its partnership with the LSRC at LSU's Center for
GeoInformatics. NGS publishes it's subset of the GULFNet CORS data through
their CORS website found at the following links. https://geodesy.noaa.gov/corsdata/ NOAA's National Geodetic Survey (NGS) operates the Continuously Operating Reference Station (CORS) network that consists of group of Global
Navigation Satellite System (GNSS) reference stations which provide code
range and carrier phase data to users in support of postprocessing
applications. The stations are owned and operated by federal, state, local
agencies, private companies, and university groups, and NGS redistributes
their data to the public free of charge. The GNSS data collected at these stations are made available to the public
by NGS in Receiver INdependent EXchange (RINEX) format. The data include
observation, meteorological, navigation/ephemeris, station logs and NGS
coordinate files for the stations. Most data are available within 1 hour
from when they were recorded at the remote site, and a few sites have a
delay of 24 hours. ACCESS TO DATA ================= Data can be retrieved via HTTPS with your browser from geodesy.noaa.gov
https://geodesy.noaa.gov/corsdata/ Alternatively a customized data request service is available at: http://geodesy.noaa.gov/UFCORS FILE RETENTION POLICY ====================== RINEX observation, meteorological, navigation and TEQC summary files: Hourly files are only kept for 2 days. Daily files are kept permanently, However after 30 days the 24hr (daily) RINEX observation files that are
gzipped ({ssss}{ddd}0.{yy}o.gz) are decimated to a 30 second sampling rate
equivalent to the {ssss}{ddd}0.{yy}d.Z site specific GPS navigation files
are only kept for sites that NGS submits to the IGS network Meteorological
files are available only for sites with independent meteorological sensors. After six-months to one year the second copy of the RINEX observation
files that are gzipped is removed i.e. file name {ssss}{ddd}0.{yy}o.gz. All orbit files are kept permanently Coord files are updated as needed Logs files are updated as needed Plot files are updated daily NGS CONTACT INFORMATION ================================== If you have questions about this file or about CORS in general please check http://www.ngs.noaa.gov/CORS/ http://alt.ngs.noaa.gov/CORS or email ngs.cors @ noaa.gov


Bill Henning, NGSThe LSU Center for GeoInformatics hosted a training session on Best Methods to Achieve Accurate, Repeatable Orthometric Heights Using Real Time GNSS Networks. The event was held at the Orleans Parish Levee District Offices in New Orleans, Louisiana on August 15th 2012. The event was attended by over 60 individuals including surveyors, engineers, local, state and federal government officials. 

Some of the topics covered were:

  • Vertical Geodetic Control in Southern Louisiana
  • Providing the National Spatial Reference System in dynamic regions
  • Intro to GNSS
  • Guidelines for Establishing GPS-derived Ellipsoid Heights
  • Guidelines for Establishing GPS-derived
  • Orthometric Heights
  • Improvements to the Geoid Model
  • Real-time Kinematic Surveying and Best Practices
  • Introduction to Real-time Networks

The South Louisiana Flood Protection Authority District - East has made these trainings a Requirement for Professionals Working for the Levee District. Surveyors and Engineers that attended also received 8 Continuing Education Credits. The training provided professional Land Surveyors the requisite training to properly use an RTN system such as GULFNet or C4Gnet to provide current correct elevations. The main speaker was Bill Henning of NGS, one of the premier experts in the GNSS applications field. Registration, food and refreshments were handled by LSPS District 1 and plans are currently in the works to host additional events of this type in Baton Rouge and Shreveport in the near future.

If you are interested in attending one of these training events please sign up for the C4G mailing list or follow C4G in social media on Twitter, Facebook or the C4Gnet RSS feed. You can also find Podcasts, PDF's and Videos of past events on the C4G website or the C4G YouTube channel.

    The Center for GeoInformatics (C4G) in the Department of Civil and Environmental Engineering (CEE) recently received new geodetic instruments to model the Earth’s gravity field. A Scintrex CG-5 Relative Gravity Meter, Leica T60 Total Station, and Trimble R10 GPS Rover Kit were acquired as part of an enhancement grant sponsored by the Louisiana Board of Regents. Drs. George Voyiadjis (PI) and Joshua Kent (Co-PI) led the one-year project, which ended in June, 2017. The instruments are acquired to address the needs of three objectives: First, to develop a novel, high-resolution gravity model of sea level (i.e., geoid); second, to augment knowledge of existing subsidence rates and the driving mechanisms; and finally, promote advanced geodetic research at the University.

Here, as in many river deltas around the world, land surfaces are sinking due to subsidence. On average, southern Louisiana experiences ~10 millimeters per year of subsidence.   Understanding the mechanisms that drive subsidence is essential for mitigating risk and promoting sustainability.  The CG-5 relative gravity meter supports these goals by measuring the relative differences in the Earth’s gravity across southern Louisiana.  Surveys using the total station and R10 rover kit are currently underway to geodetically correlate the CG-5 data with absolute gravity readings collected in the early 2000s by the National Geospatial-Intelligence Agency and the National Geodetic Survey. The updated gravimetric surveys conducted by C4G researchers and staff will deliver much needed insight into the variety of geophysical processes driving the spatially and temporally heterogeneous rates of subsidence measured across the state. 

In addition to the subsidence research, this enhancement grant will directly and indirectly benefit Louisiana’s geodetic stakeholder and consumer communities. For nearly a decade, the C4G has provided tools, services, and other geodetic resources dedicated to precise positioning throughout the state and across the region.  Central to these resources is the C4GNet real-time reference network.  The network includes more than 50 continuously operating GPS reference stations (CORS) installed across Louisiana.  Over the next five years, the C4G plans to geodetically correlate the gravity measurements with antenna heights at each station.   Extended surveys will include CORS in neighboring states.  When completed, the data will contribute to the creation of a novel, high-resolution geoid model that will allow the geodetic community to accurately and precisely measure elevations above sea level.

The instruments acquired by this grant represent an investment into the geodetic research capacity at the C4G and CEE.   In addition to the above goals and objectives, these resources have already been selected for use by investigators in two external funding proposals, both of which will rely on the precision of these instruments to deliver meaningful geodetic solutions.  These instruments not only promote research activities, they have galvanized national and international collaborations with partners across the US Gulf Coast and western Europe.  More information about these instruments and geodetic models is available at the C4G website www.c4g.lsu.edu or gravity.c4g.lsu.edu.

C4G CORS used in C4Gnet and GULFNet Real Time Networks have been valued at over 33 Million dollars a year according to a new government report released June 15th, 2009. The report titled "Socio-Economic Benefits Study: Scoping the Value of CORS and GRAV-D" was prepared for the National Geodetic Survey by Irving Leveson. It shows billions in estimated benefits from NOAA Positioning Products and Services:

• National Spatial Reference System (NSRS): $2.4 billion per year
• CORS: $758 million per year. (C4G has 27 of the 1324 National CORS)
• C4Gnet and GULFNet have 66 CORS with a yearly valuation of $500K each.
• GRAV-D (Once completed): $4.8 billion over 15 years, including $2.2 billion in avoidance costs from improved floodplain management.

Download the entire report!