Last year I wrote about how our datums are changing.  NOAA is working on recalibrating the nation’s elevation data as part of its update to the National Spatial Reference System, expected in 2022/23.  The height modernization program corrects local elevation data which has not been updated since 1988.  GPS and gravity mapping are being used to update elevation. 

This will have some implications, the greatest impacts will be further west and north you go, shrinking the US in the Pacific Northwest.  That mountain may not be as high as it was or your community is now in a floodplain when it wasn’t.  Click below to read more about it.