This article hopes to clear up some misunderstandings about the Garmin GPSmap 60cx receiver (no doubt others in the same range, too) and help you to understand just how the memory and memory card are used. The object of the exercise is to save a file(s) of points automatically stored whilst you are moving about. This file can then be used to geocode photographs. A key requirement is that all saved points MUST have their time as well as position.
How do you tell the GPSmap 60cx receiver to store a file of constantly updated positions whilst you are moving about? Find the 'Tracks' page, and notice that there is a dot next to 'Off'. Use the Rocker Key to highlight the word 'On', then press 'Enter' to move the dot to there. You are now recording all your moves, and will continue to do so until you change the setting back to 'Off'. These positions will be stored in a file called the 'Active Tracklog'. The 'Active Tracklog' records time, date, position, altitude, leg speed, leg distance, leg time, and leg course. To control just how it does this, and set such things as 'Wrap When Full', go back to the 'Tracks' page and select 'Setup'.
OK. We've now finished our walk, and turned the track storage to 'Off'. The obvious thing to do is to go back to the 'Tracks' page and click on the 'Save' button to save the track you've just made. WRONG! If you do that, the saved tracklog will lose its timestamps. Simple lesson: don't save your tracklog on the GPS, counter-intuitive though this is!
If you just want to store your track the track you have just made, you need to access the 'Active Tracklog' with some suitable software. I would suggest the free and excellent program 'DNRgarmin' which you can find out about, and download, by clicking here. Install and start the program, then click 'GPS >> Open Port'. The program will tell you what kind of GPS it is seeing. Then click 'Track >> Download' to grab the entire Active Tracklog. You can then save this by clicking 'File >> Save to >> File', and choosing 'Save as Type' as Text File. All your track will be saved, and no data will be lost. You can open it up in 'Notepad' to see for yourself.
The above notes are all very well as long as the tracks you want to store are in the Active Tracklog. But what happens if you are going on an extended walking tour, and want to save the tracks for your entire trip? The Active Tracklog can only save 10,000 points. After that, the recording will stop, or will be over-written, depending on how you have configured the Tracks Setup page. The answer is to set your Garmin GPSmap 60cx receiver to save tracks on to the removable Micro SD card, which lives in the rear compartment, just under the batteries. It will automatically save a separate file for each day, and will continue to do this as long as there is space on your Micro SD card. These .gpx files saved to the Micro SD card do NOT lose any data. The number of files on the card are only limited by the size of your card. In practise they take up very little space on the card - typically 120 bytes per trackpoint. That's approximately 8.3 million trackpoints on a 1GB card. In other words, if you are recording at the rate of 1 per second, 24 hours a day, it would take 96 days to fill up!
You can delete your Active Tracklog, which is saved in the main memory, at any time, but the GPX files will remain on the Micro SD card and do not affect the number of trackpoints in the main memory. Note that tracks stored on the card cannot, however, be displayed on the screen. You can only display the contents of the Active Tracklog on the screen, which effectively means you can only display (at most) the last 10,000 recorded track-points.
To access the files in the Micro SD card, you need a PC with Windows XP or above. Connect your Garmin GPSmap 60cx receiver to the PC using the USB lead supplied. Put the GPS in Mass storage mode: Main Menu >> Setup >> Interface, and click the 'USB MASS STORAGE BUTTON'. Back on your PC, start 'My Computer' and look for 'Removable Disc' - this is the SD datacard in your GPS, and will contain .gpx files for each automatically saved track. They will be named with the date: 'YYYYMMDD.gpx', and can be copied and pasted to another folder on your PC for later use. To end the USB mass storage mode, simply eject by clicking on the 'Safely Remove Hardware' button in the System Tray. The GPS will then reset to its normal mode.
To do useful things with these .gpx files, start the DNRgarmin program, choose File >> Load from >> File, and navigate to one of the .gpx files. Define the file as Point, Track, or Route when asked, and DNRgarmin will import and display the track. To export, choose File >> Save to >> File, then chose the format from the drop-down 'Save as type' box. You can also geotag photos with the excellent 'RoboGeo' program - see my last Blog entry: 'How to Geo-Tag Photos' for details.
Finally, I'd like to mention that during my research, noting all the details down as I discovered or amended them, this article almost wrote itself. If everyone noted down things during their researches, then published the notes on a Blog, we'd all save a lot of time!
