Vertical datum conversion how to#

However, the North American Vertical Datum of 1988 (NAVD 88) is now the national standard. Historically, the standard datum used by the federal government was the National Geodetic Vertical Datum of 1929 (NGVD 29). What is a Vertical Datum?Ī vertical datum is a base measurement point (or set of points) from which elevations are determined.

If you have additional questions regarding vertical datums not answered on this page or require additional assistance, please call the National Flood Insurance Program Help Center at 1(800) 427-4661 or contact the FEMA Map Information eXchange.

Vertical datum conversion how to#

Here’s a look at what vertical datums are and how to use them with the updated maps, in question and answer format. The elevations shown on the ABFE maps, preliminary work maps and preliminary FIRMs released by FEMA are referenced to the North American Vertical Datum of 1988 (NAVD88). Learn more about how FEMA recommends this information be used on the Using FEMA Flood Hazard Data page. To accomplish this, FEMA has released updated flood hazard data for certain coastal communities in New Jersey and New York affected by Hurricane Sandy, in the form of Advisory Base Flood Elevation (ABFE) maps, preliminary work maps, and preliminary Flood Insurance Rate Maps (FIRMs). The Federal Emergency Management Agency (FEMA) is committed to continuing the recovery process in New Jersey and New York by providing the best assessment of flood risk to help guide communities in their efforts to reduce the impact of flood events and protect lives and property from future damages. Understanding Vertical Datums: Frequently Asked Questions