Tag Archives: NAD_83

Site velocities with respect to NAD 83(2011) epoch 2010.00. Credit: National Oceanic and Atmospheric Administration (NOAA).

Datum Epochs, And How to Understand Them

Understanding datum epochs for accurate measurements and locations in dynamic tectonic areas. What are datum epochs? Let’s start at the beginning. “Epoch” is a scientific term used to denote a specific moment or period in time. Land surveying and geodesy use a numerical “epoch” in decimal years to state the moment at which a given...