Especially if you work with geospatial and/or geomatic data on a regular basis as a surveyor, geodesist, cartographer, or another profession, you need to keep in mind that previous datums will no longer be accessible after the transition. They will become historical data.
Big changes are coming to the United States National Spatial Reference System (NSRS), as the current geodetic reference datums used for surveying – the North American Datum of 1983 (NAD83) and the North American Vertical Datum of 1988 (NAVD88) – become things of the past.
Here’s what’s happening.
The plan is around 2024 – 2025, NSRS will do away with its current geodetic reference datums, NAD83 and NAVD88, which define reference points for survey mapping by using physical survey marks (or benchmarks). Currently, the NAD83 defines horizontal datums and the NAVD88 defines vertical orthometric heights based on sea-level. Replacing that datum system will be a fully modernized, digital reference system defined by Global Navigation Satellite System (GNSS) technology and gravimetric geoid modeling.
As NGS Director Juliana Blackwell has said, we must stop referring to datums as datums; instead, calling them reference points would be more apt. Instead of NAD83, we’ll have a geometric reference frame defining latitude, longitude, and ellipsoid height. Instead of NAVD88, we’ll have a geopotential/vertical reference point defining elevation, time, and gravity.
What’s the reason for this change?
The coming transition from the old system of datum referencing to the new system of reference points will not only improve accuracy of positioning and consistency within surveying, mapping, and navigation, but will also align us more closely with international reference points used by surveyors around the world. As surveyors and engineers cross countries, even continents, to work, learning a new system entirely to do the job will be rendered unnecessary. In other words, mapping will have a universal language across the board to communicate surveys of the earth.
Who is impacted?
The new datums will particularly impact individuals involved in geomatics and geospatial data recorded prior to 2022 datums; including those in mapping and navigation, demography, surveying and engineering, science, and transportation industries.
The challenge for these industry workers will be in converting old coordinates to new ones, as well as updating official documents as needed.
Why is this happening?
Simply, the earth is not a perfect ellipsoid. Datums currently cannot account for the varying degrees of elevation and have irregularities that affect measurement accuracy.
How will the new reference points benefit us?
The new reference system will improve the accuracy of results and enhance accessibility since GNSS equipment is fast, inexpensive, reliable, and reduces reliance on finding survey control or “benchmarks.” They will also create consistency across the board.
Jim Baumann, International Marketing Writer and Editor for ESRI, explains in regards to the new datums will enhance efficiency. “Efficiency will be another big motivator for using the new datums, especially in the vertical. The ability to get accurate elevations from satellite data in mere seconds will be a tremendous benefit. The goal is to provide GNSS-derived orthometric heights at an absolute accuracy of four centimeters (at 95% confidence).”
Going forward and avoiding geospatial pitfalls.
Especially if you work with geospatial and/or geomatic data on a regular basis as a surveyor, geodesist, cartographer, or another profession, you need to keep in mind that previous datums will no longer be accessible after the transition. They will become historical data.
To combat these issues, the NGS (National Geodetic Survey) – the governmental agency who is responsible for establishing and maintaining the NSRS – has been developing a plan to move away from using geodetic datums. NGS has recently released a revised version of Blueprint for the Modernized NSRS, as well as several webinars released publicly, all to help teach how to convert the old data into the new reference point system. Please click on the links for more information.
Remember, the upcoming NSRS geodetic reference points are not an update – they are a total revision, with new tools and ways of measuring.
As with any big change, difficulties will always arise and it’s good to stay realistic and be prepared. And ask yourself, do you have a plan for transforming your firm from the old system of datum referencing to the new system of reference points?