Get Prepared

1. For Legacy Data: Evaluate your existing geospatial data, related products, and their accuracy requirements

NGS’ 2021 Blueprint for the Modernized NSRS, Part 3: Working in the Modernized NSRS has a series of Use Cases, the third of which (page 92) covers ‘Transitioning Data to the Modernized NSRS’. Three methods for transitioning existing data are described:

1. Resurvey: Return to the field and collect new observations, relying on geodetic control that has coordinates in the new datum
2. Readjust: Using existing observations, re-compute new coordinates based on geodetic control that has been defined in the new datum
3. Transform: Take finished products that have coordinates in the old datum and use transformation software to estimate coordinates in the new datum

To inform your decision on which of these methods is appropriate, evaluate your accuracy requirements, any remaining original observations, and the metadata for your existing geospatial data and products. In many cases, if collecting new observations or reprocessing original observations is not feasible, transforming the data will be the only option.

To prepare your data for transformation to the new system and to check whether you have the appropriate metadata to do so, run your data through the NGS Coordinate Conversion and Transformation Tool (NCAT) to transform to the current datums (NAVD 88, NAD 83 [2011]). When the modernized system is released, NCAT will be updated to transform your coordinates from current datums to coordinates in the modernized NSRS at its first reference epoch of 2020.00.

2. For New Data: Save Observations and Record Metadata

Knowing the datums and epochs (aka timestamps) for your geospatial data will simplify your datum transformations. Therefore, it is strongly advised to require complete metadata in all surveying and mapping contracts and to save all of your original observation files

3. Review State Plane Coordinate System of 2022 (SPCS2022) requirements

The preliminary data and parameters for SPCS2022 zones are available on the Alpha Preliminary Products page. Consult the basic or interactive online maps made available on the Alpha page for the most up-to-date information on SPCS2022.

4. Prepare to update legislation, as needed

The National Society of Professional Surveyors (NSPS), the American Association of Geodetic Surveying (AAGS), and NGS created template legislation to aid states in transitioning their legislation from wording that supports the current datums (NAD 83, NAVD 88) to new wording that more generally supports the NSRS without explicitly naming datums. Contact NSPS, AAGS, your NSPS state affiliate organization, or your local geospatial professionals group for more information. Examples of new state legislation are available for download.

See Appendix C of NOAA Special Publication NOS NGS 13 for a table listing SPCS 83 legislation adopted by U.S. states and territories. Only California has legislation for a vertical datum, in California Public Resource Code, Division 8, Chapter 5: 8890-8902.