How large is the North American Datum (NAD) 27 to NAD 83 shift?
Within the conterminous 48 states, the NAD27-NAD83 shift of the latitude/longitude graticule (lines showing parallels of latitude and meridians of longitude for the earth) is in the range of 10-100 ground meters. Changes to UTM values are generally larger, around 200 meters, and changes for other coordinate systems are different. For more detail about the effects of datum changes on USGS quadrangle maps, see this technical paper.
Related Content
Why are the historical maps referenced to outdated datums?
Why are the NAD 83 position values so far from the NAD 27 values? Were the old coordinates wrong?
How are different map projections used?
What location coordinates (datum) does the Geographic Names Information System use?
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