U.S. flag

Yon sitwèb ofisyèl pou gouvènman ameriken an

Dot gov

Official websites use .gov

A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS

A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites..

alert - warning

Yo pa tradui paj sa a nan lang Kreyòl ayisyen. Ale sou Kreyòl ayisyen paj la pou jwenn resous nan lang sa a.

North American Vertical Datum (NAVD) of 1988

The vertical control datum established for vertical control surveying in the Unites States of America based upon the General Adjustment of the North American Datum of 1988. It replaces the National Geodetic Vertical Datum (NGVD) of 1929.