Wisconsin Airport FAR Part 77 Imaginary Surfaces are established with relation to the airport and to each runway. Imaginary surfaces include Primary, Approach, Transitional, Horizontal and Conical and are defined in https://www.ecfr.gov/current/title-14/chapter-I/subchapter-E/part-77/subpart-C/section-77.19. Surfaces were drawn using the Esri Airports FAA FAR 77 tool (Aviation Airports license). The size of each surface is based on the existing approach category for each runway end when this data was last updated.

Imaginary surfaces were created with respect to existing runway centerlines and airport elevations managed by the Wisconsin Department of Transportation's Bureau of Aeronautics from data published by the Federal Aviation Administration (FAA) in the Airport Data and Information Portal at: https://adip.faa.gov/agis/public/#/public. This data is updated annually or as needed and may not represent current conditions at an airport. FAA's ADIP site contains the most current airport and aeronautical data available.