This is a section of the aprs.fi user guide.
The APRS data export tool allows you to export and download APRS positions from the aprs.fi database. An aprs.fi user account is required for using this tool. If you have not logged in already, a login form will be presented.
The tool can export to KMZ format (zip'ed KML + embedded symbol graphics in the same file) which can be opened in Google Earth, and some third-party software tools can also digest the KML file inside the KMZ archive.
It can also export to CSV which opens up nicely in Excel, and both JSON and XML (for the programmers out there).
This feature is aimed at people who wish to download their balloon's track afterwards, or their path to Dayton and back. It's not aimed at people who wish to download the whole aprs.fi database, so it's rate limited quite heavily – you can only use it a few times per day. Also, it's not an API.
The KMZ format is described by Google's KML documentation.
The CSV file is comma-separated, with dates in YYYY-MM-DD HH:MM:SS format in UTC.
Coordinates are provided in decimal format, north and east being positive. Other measurement units are metric: speed in km/h, altitude in meters, distance in kilometers.
The JSON and XML files use the Unix timestamp format (seconds since 1970-01-01 00:00:00 excluding leap seconds), which can be converted to UTC using gmtime() and local time using strftime() functions (and their relatives in other programming languages).
aprs.fi user guide