Modern society depends on geographic data that is accurately and reliably spatially referenced. In response to this and the decreasing availability of up-to-date traditional control (reference) data LSU C4G & LSRC has initiated and is developing – GULFnet. The initial implementation of the statewide geodetic network, as detailed herein, had its genesis in 2002 by Professor Roy Dokka with the partnership between the LSU Center for GeoInformatics (C4G) and NGS creating the Louisiana Spatial Reference Center (LSRC), which has developed a master plan for a modern statewide geodetic control network for Louisiana and the Gulf Coast.
It inherited earlier efforts from Professor Gary Kelly and the LSU Remote Sensing and Imagery Laboratory of the Civil Engineering Department. located on the rooftop of the Center for Engineering and Business Administration (CEBA) Building (now Patrick Taylor Hall) and a Cooperative Base Network Control Station named “LSU 1”. Part of the High Accuracy Reference Network (HARN). It was also designated as a Continuously Operating Reference Station (CORS). LSU 1 was updated with newer equipment and designated 1LSU In 2003.
According to plan, each network station shall have at least the following geodetic values – latitude, longitude, northings, eastings, height (orthometric & ellipsoidal), velocity (magnitude & direction), and stated accuracies. This network will also achieve the goals of the federal National Height Modernization initiative as determined by the LSRC in consultation with NGS.
C4G’s mission is to be the vanguard for providing and ensuring an accurate, precise, and consistent geographic reference framework for the State, utilize the positional data collected over time to produce an exceptional level of research and service to the State for mitigating the hazards attributed to subsidence.
LSRC’s goal is to establish a geodetic control network consisting of Continuously Operating Reference Stations (CORS) statewide control network (GULFnet). However, the implementation includes passive (in-ground) stations, as well as CORS, primarily because of their value for monitoring geologic changes and historical significance, as well as educational laboratories. The master plan includes systematic network maintenance procedures that minimize the unique challenges within Louisiana to maintain control values up to date, i.e., procedures that monitor temporal changes in geodetic coordinates due to subsidence, tectonic motion, and anthropogenic activity.
The described statewide network fully utilizes the existing CORS and related data-processing infrastructure that have been established by decade of investments, totaling over millions of dollars. Thus, the planned network not only provides an accurate, consistent foundation for Louisiana’s spatial referencing needs, but also facilitates the continuation of this vital scientific research.
CORS are to be located throughout the state with the goal of a nominal spacing of 70 kilometers (43 miles). Passive stations (in-ground monuments) are an accessory to the network supplementing the CORS and function as sensors for more detailed observations the geologic changes. Pre-existing passive stations exist primarily along selected transportation corridors and other areas, primarily set previously by others. New passive marks are often established as reference marks for CORS and/or as gravity monuments and some for student training.
The implementation, as outlined, can be accomplished as sufficient funds are available. This includes constructing new CORS, installing new passive station monuments, and performing observations, data processing, and adjustments for the entire network. The on-going support and maintenance efforts are accomplished by LSRC staff. The operational costs tend to be less than $1 million annually and are currently achieved through the support of subscribers to the Real-Time-Network services (C4Gnet.XYZ).
C4G and the LSRC have received outside support from time to time from NSF, NGS, NGA, the Legislature, the LSU Board of Regents, La. DOTD and others. At present, there are no grants or other funding sources. Annual (on-going) funds are critical to the long-term success of the network because of the cost of equipment improvement and maintenance as well as the significant geologic motion and subsidence issues throughout Louisiana.
Access to the GULFnet basic geodetic data, is available at no charge to all users. The C4Gnet.XYZ service is available by subscription and is the foundational funding for minimal day-to-day operations.