With the HcX, I think once the file is save to the SD card it can only be viewed and/or exported from an SD card reader. I don't think the GPS unit accesses the saved file from the SD card. I know I have to remove the card from my HcX and read the SD card straight from my computer.
Related question: When the HcX is set to record to the SD card, does it simultaneously record to internal memory and the card? Sometimes I get the memory is 99% full and assumed that was internal memory. At what point does the HcX save the track to the SD card?
Ok I got out the GPS and played with it to try to figure out some of these answers.
The only way that I have found to retrieve the auto-saved tracks is to take out the card and download manually.
1. It records to Internal Memory when you have the Track Log On radio button selected under: Tracks > Track Log ON or OFF.
2. It will record to internal memory and to the SD when you have done step 1 above and also checked the "Log track to data card" under: Tracks > Setup > Data Card Setup > Log Track to Data Card.
It will NOT record to SD without BOTH 1 and 2 above selected to save track.
Yes it saves both to internal memory and SD but you can clear the internal memory of the saved track easily when it starts getting full or just have the "Wrap when full" checked under: Tracks > Setup > Wrap when full.
This internal memory is additional storage to your uploaded tracks so if you have uploaded all available memory it saves some space for the tracks to be saved to internal memory. The tracks it saves to internal memory contain very basic information. The tracks saved to the SD contain the detailed information such as speed, alt. etc.
Ron - You should be able to save the 21ish day trip to a 4 gig memory card. I had about 5 days worth of tracks in mine and it said the memory was only 1% full.