Vertical datum conversion how to#

Geodesists and surveyors use datums to create starting or reference points for floodplain maps, property boundaries, construction surveys, levee design, or other work requiring accurate coordinates that are consistent with one another.

Vertical datum conversion how to#

For instance, when you want to tell someone how to get to your house, you give them a starting point that they know, like a crossroads or a building address. In this way, datums act similar to starting points when you give someone directions. When it is completed, users will be able to get accurate heights to within about an inch for most locations around the nation.Ī geodetic datum is an abstract coordinate system with a reference surface (such as sea level) that serves to provide known locations to begin surveys and create maps. This project is called the Gravity for the Redefinition of the American Vertical Datum, or GRAV-D for short. Scientists at the National Geodetic Survey are working on a long-term project to make accurate height measurement better, faster, and cheaper.This update will deliver more accurate water level measurements throughout the Great Lakes. and Canadian partners are undertaking a multi-year initiative to update the International Great Lakes Datum. This update will help improve navigation safety, storm surge prediction, sea-level monitoring, and ecosystem research.

Scientists with the Center for Operational Oceanographic Products and Services are updating the National Tidal Datum Epoch - the framework used to measure water levels along U.S.