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Is there a way to transform between NAD27 and NAD83?
Two such methods for transforming between NAD27 and NAD83 have been developed by the United States and Canada for use in their respective countries. NADCON, an acronym for North American Datum Conversion, is a datum transformation program created by the U.S. National Geodetic Survey (NGS).
How much uncertainty is there in transforming coverage between NADCON and NAD83?
In areas of sparse geodetic data coverage, NADCON may yield less accurate results but seldom in excess of 1.0 m. Transformations between NAD83 and the States/Regions with High Accuracy Reference Networks (HARN) introduce approximately 0.05 m uncertainty.
When did the North American Datum change to NAD 83?
The readjustment of the North American Datum of 1927 (NAD 27), Old Hawaiian Datum and Puerto Rico Datum to the North American Datum of 1983 (NAD 83 (1986)) in July 1986 was both a change in reference ellipsoid and a “clean up” of nearly 200 years of surveying data held by NGS.
How is NADCON used to convert datums?
NADCON was developed in order to facilitate conversion between the datums,. The grids used by the program are based on more than 150,000 horizontal control points whose coordinates reside in NGS’ data base, and provide transformed positions based on the shifts of the control nearest to the input position.
Which is a common transformation between NAD 1983 and WGS 1984?
A common transformation in North American data is between NAD 1983 and WGS 1984, such as between the GCS_North_American_1983 and GCS_WGS_1984 geographic coordinate systems. See ESRI Support KnowledgeBase article 24159 for tips on how to determine which transformation to use between NAD 1983 and WGS 1984.
Is the North American Datum ( NAD ) based on NAD83?
Adoption of the North American Datum (NAD) of 1983 requires that you store and use map data in a coordinate system based on NAD83. However, many of you might have automated your original data layers using NAD27 and continue to do so, primarily because some source data is collected from maps based on NAD27.