Quote:
Originally Posted by KC911
So tell me about elevation....
Are all these topo maps and surveys gonna be wrong when the sea level rises a foot?
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THE DATUM has a date as of 1927 for the standard stuff
then they were switching to 1983 when I quit in 2000
they do not adjust it very often
https://www.usgs.gov/faqs/how-large-north-american-datum-1927-nad-27-nad-83-shift
it is just numbers avg over a time
and tides vary by air pressure wind direction also