What are NGVD 29 and NAVD 88?
**NGVD/NAVD questions shown below were taken from National Geodetic Survey website** “The National Geodetic Vertical Datum of 1929: The name, after May 10, 1973, of (the) Sea Level Datum of 1929.” (vertical control datum established for vertical control in the United States by the general adjustment of 1929.