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FAQ: How do I know if a fixation is in a specific Interest Area?
#1
A fixation is assigned to an Interest Area if its average gaze position—calculated from all the data samples that make up that fixation—falls within that area's boundaries.

The easiest way to understand this is in the Spatial Overlay view, where the center of each fixation circle represents this average position:
  • Center: The center of the circle marks the average (X, Y) gaze position for that fixation. You can see the precise pixel coordinates in the Inspector window (look for Avg. X Position and Avg. Y Position).
  • Size: The diameter of the circle represents the fixation's duration.
Important: A fixation is assigned to an Interest Area (IA) only if the center point of its circle falls within the IA's boundaries. A simple overlap of the circle's edge is not enough to count as a hit.
   

To see which IA each fixation was assigned to, you can generate a Fixation Report (Analysis > Reports > Fixation Report).

In the report, look for variables that begin with CURRENT_FIX_INTEREST_AREA. The following are particularly useful:
  • CURRENT_FIX_INTEREST_AREA_ID: The numerical ID of the IA.
  • CURRENT_FIX_INTEREST_AREA_LABEL: The text label of the IA.

For Overlapping Interest Areas
For more information on how fixations are handled when Interest Areas overlap, please see this guide: How do events get assigned to multiple overlapping Interest Areas?