[Proj] Help translating NAD83 coordinates to WGS84

John D. Evans jdevans at gst.com
Mon Sep 20 13:16:38 EDT 2004


Can someone point me to an authoritative, published (pref. online) 
reference that states an upper bound on the difference between NAD83 and 
WGS84 over North America?

I went looking for such a reference some time ago and the best I could 
find was some NIMA or DMA Technical Report that said the two differed 
"in some places by a meter or more".

Ed McNierney wrote,

>> In North America, NAD83 and WGS84 coordinates are so extremely
>> similar that no conversion is necessary or appropriate in most
>> cases.  Unless your data is acquired with a precision of
>> millimeters (literally) you can treat the two datums as identical.
>> Most applications do that.


   - John D. Evans, Ph.D. <jdevans at gst.com>
     Global Science & Technology, Inc. (GST)
         Geospatial Interoperability Group
     1-240-542-1133  /  1-301-286-0803

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