Not too sure exactly what you are asking, if you mean load parts (tiles) of an existing map in basecamp onto your device, this is possible but a bit of a pain. Used to be easier in mapsource ,but is rather more convoluted in basecamp.
I do not really understand your question about a gpx.
If it is a gpx track, this can be used on a device with no underlying mapping, if a gpx route file it will look for a routable map on the device.
The image is a gpx track on a device with no maps.
Not too sure exactly what you are asking, if you mean load parts (tiles) of an existing map in basecamp onto your device, this is possible but a bit of a pain. Used to be easier in mapsource ,but is rather more convoluted in basecamp.
I do not really understand your question about a gpx.
If it is a gpx track, this can be used on a device with no underlying mapping, if a gpx route file it will look for a routable map on the device.
The image is a gpx track on a device with no maps.