How is airport pattern altitude on the Airports page determined?

We receive our pattern altitude information from AOPA.  Traffic Pattern Altitude (TPA) is listed in the A/FD.  If the TPA is not published, then the pattern altitude is determined by our AOPA source utilizing local sources for the best information.

Image 1:  TPA published in A/FD is displayed in the information section for this airport.

 

Image 2:  AOPA sourced pattern altitude since no TPA is published in the A/FD.