This video describes what datums are and how datums are derived from true geometric counterparts just as simulated datums are derived from datum feature simulators.
See my playlist of other definitions here: https://youtube.com/playlist?list=PL37yq0C_XXoycVR3EqmTTIXvIbOWumTJo&si=psqt2ZJ39Mee0aRz
