I am not sure if there is any specific rules for use, Fanuc programming manuals generally use the one you show to indicate the Work coordinate ref points G54-G59 etc, except the opposite quadrants to the one shown are shaded.
Fanuc designation show the Machine origin a bit different with an inner circle with the top left quadrant of the inner circle only shaded.
If you have access to a Fanuc programming manual it could help show it, I also have some CNC programming manuals that indicate the same for the most part, with a few minor differences.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.