Navigate to map screen and then press Menu button (left hand side), then choose Setup Map option. Now navigate with joystick to right to small icon "i" Map Setup - Information. Here You can find all maps, and You can switch on/off map regions.
How to use multiple maps on 4G micro SD card in Garmin eTrex Vista HCx?
Recently I bought a Garmin eTrex Vista HCx.
I will use a 4G micro Sd card to put my maps (unlocked) on it. How to load these files on the SD card that they are 'seen' by the Garmin device?
How can I easily switch between the different maps?
What is the main purpose of "Lock On Road?" Should I turn it ON or OFF?
If you have that feature and you are driving, leave it on. If your hiking you may get better results to leave it off if there are roads or trails nearby and you are not using them. I'll try to explain.
That Road Lock feature keeps the vehicle on your map screen "locked/snapped/positioned" on the nearest road. If you shut it OFF (try it) your vehicle will appear to drift all over the place because...
(1) your actual GPS position is just not that accurate (for many many reasons) and has big variations from reality.
(2) even if your GPS were 100% accurate, your pretty maps are just not that accurate. Your maps are digitized photos at some pre determined resolution and only "approximate" where roads are really loacated. Some map areas are much more accurate than others.
So the whole point of Road Lock is a (good) compromise to deal with overally system inaccuracies and make your car appear always on the road as you are traveling when viewed on your GPS screen.
If you want to see how much variation/error there is in all of this, and have the ability in your GPS to record an uploadable "track log", upload some track into mapsource or some other tool/utility that can display your track on a map and see what ot looks like.
You may allso find times where even road lock is not foolproof. You may someday be traveling in a city with tall buildings and lots of parallel streets often to find that your GPS shows you on a street a block away (to the left or right) from where you know you are. This is often due to poor satelite reception or signal bounce (signal bounce = signal delays = mis-position)
Another way to demonstrate road lock for yourself. Just take you GPS in hand and start walking away from a road and see how long it takes before it the GPS notices/shows you have left the road. It's often as much as 75' but again, there are a lot of variables.