The GNSS Continuously Operating Reference Stations (CORS) of GULFNet established by LSU’s Center for GeoInformatics (C4G) provide the latest tools in cutting-edge technology for Professional Land Surveyors throughout the State of Louisiana. Because the land elevations are constantly changing due to geologic subsidence, the positions on the traditional benchmarks used by surveyors for centuries have become obsolete in Louisiana! Homeowners, businesses, and local governments count on reliable elevations to insure safety from flooding due to rainfall-engorged rivers as well as saltwater sheet flow effects from hurricanes. The National Flood Insurance Plan is based on surveyors providing reliable elevations on Flood Surveys for homeowner’s Flood Insurance policies. Subsiding elevations make benchmarks unreliable and useless from the Arkansas State line to the Gulf of Mexico and from The Texas State line to the Mississippi State line!
The only reliable source of correct and up-to-date elevation data in the entire State of Louisiana is done by data from the LSU GULFNet system of continuously operating reference stations (CORS). Established in accordance with Federal Guidelines and Specifications, the basic backbone of CORS in Louisiana are known as GULFNet. A subset of CORS sites in GULFNet have been adopted by the NOAA CORS Network (NCN). Raw data from these NCN sites are publicly available from C4G or NGS and can be used to perform corrections in geodesy tools or by submitting field observations to free online processing tools like OPUS offered by NGS or the C4Gnet.XYZ Online Processing service offered by C4G. All of these methods use the CORS date from GULFNet to correct the positions to agree with the NGS National Spatial Reference System. These tools are commonly used to check and verify that any data collected agree with other data processing methods before presenting final coordinates and especially final elevations.
The C4GNet.XYZ Real Time Network is another method to access corrections to survey positions in real time. The C4GNet.XYZ RTN is constrained the NGS published coordinates for all NCN stations which aligns the RTN to the NSRS and makes it possible to speed up the collection of accurate up to date elevations in real time.