V08G_25- 2007 National Readjustment of the North American Datum 1983

Welcome to 2007 National Readjustment of the North American Datum 1983! This course traces the development of the horizontal and vertical datum of the United States developed by the National Geodetic Survey (NGS) and its predecessor agencies, the Coast and Geodetic Survey, US Coast Survey and Survey of the Coast. We will also discuss the North American Datum of 1983 and its various iterations, High Accuracy Reference Network (HARN), the inclusion of Continuously Operating Reference Stations (CORS) and the relationship of NAD 83 to the International Terrestrial Frame (ITRF) and the World Geodetic System of 1984 (WGS 84). The widespread implementation of Geographic Information Systems (GIS) by state government has caused several states to consider the adoption of standard projection to facilitate statewide mapping and efficient data management. GIS require a statewide spatial database to be stored in a common projection or coordinate system to function properly. State Plane Coordinates (SPC83) is the best-known system of the standard projection in the United States and enjoys great support among surveyors and engineers. State Plane Coordinates, however, have the disadvantage of dividing states into separate zones with different projections making the existing state plane system impractical for use as the standard projection for statewide databases. Should a statewide projection be the future of an Alabama coordinate system? This topic will be discussed. 

At the end of this course, participants will be able to:

1. Describe the historical development of the horizontal and vertical datum in the United States, including the roles of the National Geodetic Survey (NGS) and its predecessor agencies.
2. Explain the key features and iterations of the North American Datum of 1983 (NAD 83), including the High Accuracy Reference Network (HARN) and Continuously Operating Reference Stations (CORS), and their relationship to the International Terrestrial Frame (ITRF) and the World Geodetic System of 1984 (WGS 84).
3. Analyze the impact of Geographic Information Systems (GIS) on state government mapping practices and the considerations for adopting a standard projection for statewide spatial databases.
4. Evaluate the advantages and disadvantages of the State Plane Coordinates (SPC83) system and discuss the potential for a statewide projection system for Alabama.