You can import five different file types - KMZ, KML, GPX, CSV, and BIN
There are three ways to import a file.
You can import a file from three different areas but all will have the same results. The waypoints or placemarks will be saved to the device in the Favorites section and the routes or tracks will be saved to the "Imported Routes" in the History tab.
If you import a BIN file from another GPS Tracks app, it will get added to the Saved Tracks section.
If you open a file from the Mail app or the Safari app then a copy of that file is saved to your device so you can import if you need to. Opening a file from the Mail app or the Safari app does not save the contents to the waypoints or imported routes sections of the GPS Tracks.
To use iTunes File Sharing you must have your iPhone plugged into your computer with iTunes running. Then select your device from the left side menu. From there select "Apps" from the top menu. This will display all of the apps that are on your device in the "Sync Apps" section. Below this will be a "File Sharing" section. This is where you will find a list of apps that you can transfer files to and from. Select GPS Tracks from the list on the left, a list of files contained in GPS Tracks will appear on the right. From this list you can add files to your device (by selecting "Add...") and save files from your device to your desktop (by selecting "Save to...").
You can open a file that is emailed to you from the default Mail app with GPS Tracks. To open the file, hold your finger on the file for two seconds until a menu appears. Select the "Open with..." option and then select GPS Tracks. In IOS 6 this process is slightly different in that the menu that appears initially after you hold your finger on the file for two seconds, should have Open in GPS Tracks option.
To use Dropbox to import files from you must allow GPS Tracks to access your Dropbox folder. All file interactions with Dropbox will be under the control of the user.
Once you have allowed GPS Tracks to view your Dropbox folder, Dropbox will create a folder named "Apps\GPS Tracks" in your Dropbox home directory. This will be the only folder that the app can access, so add the files to be imported here.
The BIN format is used to export a recorded track to be imported to another GPS Tracks app.
There are many different implementations of the KML file format. GPS Tracks only supports a subset of the tags. The tags that are supported for waypoints are the "Placemark" with a "Point". The tags that are supported for a route or a track are "LineString" with "coordinates".
All tags are supported for the GPX format.
The CSV file format can only import waypoints, it cannot import routes or tracks. The format for the CSV file is Latitude, Longitude, Name, Altitude, Notes.