Template:GCM generates an external link to an airport information page at the Great Circle Mapper website. The links are used as a reference in airport articles when a better source is not available online (such as a link to the Aeronautical Information Publication).
Usage
The template requires one unnamed parameter which can be either the IATA or the ICAO airport location identifier.
The optional source parameter can be used to specify the source of the data as shown on the website. If the source is DAFIF the template adds the text "(effective October 2006)".