Improved Vertical Datum Transformations Now Available

Currently, the NSRS contains six vertical datums for the United States and its territories. There are also superseded vertical datums that may be of interest when referencing historical information. NGS has recently expanded and improved its tools which transform heights between historic and current vertical datums.

NGS has just made available VERTCON 3.0 release 20190601. It is integrated into the NGS Coordinate Conversion and Transformation Tool or (NCAT) Version 2.0. Both of these releases provide improved and new vertical datum transformations for users.

Access Improved Vertical Transformations

NCAT 2.0 now uses VERTCON 3.0 release 20190601 grids to support:

• Transformations between the National Geodetic Vertical Datum (NGVD 29) and the North American Vertical Datum of 1988 (NAVD 88) in CONUS and Alaska.
  
  

• Transformations for vertical datums on Pacific and Caribbean islands.

   

When using these tools, please note:

• This VERTCON 3.0 release and update to NCAT 2.0 fully replaces VERTCON 2.1.
  
  
• Currently, NCAT only supports orthometric-to-orthometric and ellipsoidal-to-ellipsoidal height transformations.
  
  
• NCAT does NOT transform between orthometric and ellipsoidal heights. 

Learn more about VERTCON 3.0

Visit the VERTCON 3.0 Digital Archive  to access raw transformation data that make up VERTCON 3.0 release 20190601 (e.g., grids, images, software).   NOAA Technical Report NOS NGS 68  (PDF, 8 MB) provides detailed information on VERTCON 3.0, and the digital archive includes plots and data.

Please send questions or comments to
ngs.infocenter@noaa.gov

NOAA's National Geodetic Survey 

geodesy.noaa.gov