Wednesday, April 7, 2010

National Geodetic Survey Provides Access to New Redefined Geoid Via OPUS

Two new features on the National Geodetic Survey (NGS) Web site allow the public to preview proposed changes to the U.S. vertical datum—the system used to define the heights of geographical information, such as mountains, lakes, floodplains, and chart depths. The U.S. Geoid 2009 Web site now features an interactive lookup for comparing new and old geoid heights. The new heights are also now being displayed on NGS’s Online Positioning User Service (OPUS) extended solution reports. Planning for the new datum is in its early stages, and more details will be discussed at an NGS-led Federal Geospatial Summit in May 2010. The new height system will make official elevations more easily and reliably accessible, thereby benefitting a multitude of geospatial applications. Orthometric heights determined using GEOID2009 (and future such models) will provide increasingly accurate estimates of true orthometric heights. Such a system will be consistent across the United States and its territories and represents the future of height determination. For more information, contact Joe Evjen.