Version 1.06

A new version of the VDatum software is presently being transitioned for release on this webpage. Four new VDatum applications have been released with this software for the following areas:

* Chesapeake and Delaware Bays
* Mobile Bay to Cape San Blas, FL
* New Jersey to Narragansett Bay, including Long Island Sound
* Southern California (Morro Bay south to US/Mexico border)

Please contact Edward Myers for informaion on how to obtain the new software and applications via ftp. Existing VDatum applications have been modified to work with the new software, and specific download instructions will be made available on this website.

For all other areas, please click below.

VDatum transformation software is accessible by clicking on the geographic names on the image map of the continental U.S.

Overview

VDatum is a software tool (Milbert, 2002; Milbert and Hess, 2001) developed jointly by NOAA's Office of Coast Survey, National Geodetic Survey, and Center for Operational Oceanographic Products and Service. VDatum is designed to transform coastal elevations between 28 different vertical datums consisting of tidal, orthometric, and ellipsoidal (3-D, three dimensional) datums. Software such as VDatum become crucial for developing the geospatial infrastructure of the U.S. coastal zone,  "one of the nation's greatest environmental, social and economic assets"  (National Research Council, 2004; Report in Brief (4 pages, pdf)).

The coastal land-water interface depends on how water levels change in both space and time. To combine or compare coastal elevations (heights and depths) from diverse sources, they must be referenced to the same vertical datum as a common framework. Using inconsistent datums can cause artificial discontinuities that become acutely problematic when producing maps at the accuracy that is critically needed by Federal, state, and local authorities to make informed decisions (Parker, 2001, 2003).

Since VDatum's inception, the advancement toward a National VDatum database involves significant collaborative effort at NOAA (Parker et al. 2003; Myers, 2005 (7 pages, pdf)). VDatum for several coastal regions is now available for many important applications and technologies, such as: storm surge and coastal inundation models, tsunami research, shoreline mapping, National Shoreline definition, coastline change analysis, sea level rise impacts, nearshore bathymetry standardization, referencing of hydrographic surveys with kinematic GPS, LIDAR data collection, ecosystem resource management, navigation services, and disaster mitigation planning.

VDatum version 1.06 transformation software, geographic boundaries, and documentation for each project area are available for download as a zipped (.zip) file.  General software documentation and a datum tutorial included in each zipped file are available at --> VDatum106 (pdf). Specific project documentation accompanies each VDatum software package.

Disclaimer: Although many of the vertical datum transformations between the North American Vertical Datum of 1988 (NAVD 88) and mean sea level, and between mean sea level and the other tidal datums, are based on tidal values from the present National Tidal Datum Epoch (NTDE, 1983 to 2001), some are based on data from older tidal epochs. NOS is in the process of updating the data in VDatum to conform to the latest NTDE. In the meantime, care should be used when applying these transformations.

For further information, contact:

Tidal Modeling Questions
Dr. Edward Myers
Coast Survey Development Laboratory
NOAA National Ocean Service

Geoid and VDatum Tool Questions
Jason Woolard
National Geodetic Survey
NOAA National Ocean Service

Bathymetry Questions
Michael Brown
Coast Survey Development Laboratory
NOAA National Ocean Service

Topography and Merged Data Questions
Stephen White
National Geodetic Survey
NOAA National Ocean Service