FAQ: How do I know if a fixation is in a specific Interest Area?
In the Spatial Overlay view, the location of a particular fixation is relative to the center of the circle that represents it. The precise location in pixel coordinate of any fixation can be found in the bottom panel of the Inspector window in the Data tab (Avg. X Position and Avg. Y Position). The overall size of each circle represents the duration of the given fixation. So, if the center of the circle falls within a given Interest Area it will be counted as being within that Interest Area. However if only the edge of the circle overlaps with the Interest Area then it is likely that it will not count as being within that Interest Area.


Additionally, the Interest Area to which a fixation is assigned can be obtained from a Fixation Report (Analysis menu -> Reports -> Fixation Report). Any of the variables beginning with CURRENT_FIX_INTEREST_AREA* refer to the Interest Area associated with the current fixation.

CURRENT_FIX_INTEREST_AREA_LABEL and CURRENT_FIX_INTEREST_AREA_ID are particularly useful for identifying the Interest Area with which the fixation is associated.

See How do events get assigned to multiple overlapping Interest Areas? for more information about how fixations are assigned to multiple Interest Areas.