The geolocation system search pulls in the user’s geolocation settings (if they allow that access in the browser setting)
The search will find the system that the user is in, or find the closest system to the user’s latitude and longitude
If the user does not enable geolocation or no location is found, they can use the community/system search input below
A list of matching systems will appear as the user types, but they can only submit it when there is only one matching system left
The system’s polygon bounds are set in Appearance > Customize > Transit System Settings and are set as a comma-separated list in the format of (long, lat, 0 long, lat, 0)

Transit System Geolocation