Garmin G3X Pilot's Manual page 288

Additional Features
Zero Pitch
Line (ZPL)
Flight
Path
Marker
PATHWAYS
NOTE: Pathways and terrain features are not a substitute for standard course
and altitude deviation information provided by the CDI, VSI, and VDI.
NOTE: Pathways boxes may not be displayed for holding patterns, procedure
turns and certain portions of the flight plan being received from an external
GPS navigator.
Pathways provide a three-dimensional perspective view of the selected route of
flight shown as colored rectangular boxes representing the horizontal and vertical
flight path of the active flight plan. The box size represents 700 feet wide by 200 feet
tall during enroute, oceanic, and terminal flight phases. During an approach, the box
width is 700 feet or one half full scale deviation on the HSI, whichever is less. Other
than the descending portion of an ILS or WAAS GPS approach (starting from the leg
leading into the FAF), pathways boxes are shown at the level of the altitude bug.
266
Synthetic Vision on PFD
Garmin G3X Pilot's Guide
Airport
Runway
190-01115-00 Rev. K