Coordinate Reference Systems
Remarks
In this area the NGVD29 vertical reference surface is approximately 0 to 0.5m above the NAVD88 surface. Interpolation within the gridded data file may be made using either NAD27 or any of the realisations of NAD83 applicable to US conus.
Frequently Asked Questions
What is the accuracy of the NGVD29 height (m) to NAVD88 height transformation?
This transformation (EPSG:7971) has an accuracy of 0.02m using the Vertical Offset by Grid Interpolation (VERTCON) method. Area of use: USA - CONUS east of 89°W - onshore.