Allen Nobles, SAM Senior Vice President, Survey, will be a featured presenter at the South Florida GIS Expo providing insight on the new geometric and geopotential (vertical) datum to be released in 2022 by the National Geodetic Survey (NGS). This new shift for horizontal and vertical datums is part of the National Spatial Reference System’s (NSRS) plan to update the existing systems. This change in system also results in the establishment of new Florida State Plane Coordinate (SPCS) zones that serve as the base coordinates for most of the mapping in the US.
The NGS has a 10 year plan to modernize and improve the NSRS to provide attention to accuracy, time-changes, improvement of products and services, and replace The North American Datum of 1983 (NAD 83) and the North American Vertical Datum of 1988 (NAVD 88). These new reference frames will be easier to access and to maintain than NAD 83 and NAVD 88, which rely on physical survey marks that deteriorate over time. The new geometric datum will also change latitude, longitude, and ellipsoid height by between one and two meters and change heights on average 50cm (20″), with a one meter (39″) tilt towards the Pacific Northwest.
Nobles will offer an overall history about the NSRS, the importance of the datum change, and the new GRAV-D gravity model for vertical elevations. The GRAV-D project consists of two major components: (1) collecting airborne gravity above the United States to capture a “snapshot” of gravity across the country to build an accurate geoid model at a specific epoch and (2) monitoring the changes to the geoid over time using a combination of satellite and terrestrial measurements and geophysical modeling.
Nobles will also expand on the Florida Stakeholders involvement with establishing new SPCS zones to reduce linear distortion in survey measurements. With the new geometric and geopotential datum affecting the southeastern U.S., all agencies responsible for geographic data will be required to use the new reference frames.
With over 40 years of experience, Nobles continues to educate professionals on the emerging surveying trends that are affecting the industry. Nobles is also a member of the Florida Surveying and Mapping Society (FSMS) and the Florida Geospatial Users Group. Information on the South Florida GIS Expo can be found at the South Florida GIS Expo website.