One of the things that I like to carry with me when I'm out taking photos is a GPS system about the size of a 9 volt battery. It has its own rechargeable battery that you can charge either on your computer or with optional car charger you can charge it while you drive.
I'm not so good at writing down where I take my photos so sometimes I realize I'd like to go back and take a different photo but I'm not really sure where I was. This little device helps me keep track of that.
What it does, after you charge it up of course. Once you turn it on and get the signal that it has picked up the satellites it will record your movements every eight or so seconds. So you can turn it on and walk around or drive someplace and take photos. When you get home you can download the info into your computer and it will sync your photos to the time of your camera. They both have to be set to the same time first.
You will also get a Google map of where you went, that you can share if you choose.
I've used it several times while on trips and I've enjoyed the results. I have had a couple photos that were misplaced and I'm not sure how that worked out but I was able to figure out the real location easily. I had taken photos in two different locations about a mile apart and for some reason the photo sync had me taking one photos at one location and the next photo about a mile away and then the next photo I was back to the first location.
Because of my bad documentation history and the desire to sometimes get back to an unfamiliar location this device works really well for me. When I download the info onto my computer it is all there already. If I want to go back I know how to get back by looking at a map and not just grid co ordinates.
You can check out the details at www.i-gotu.com.
Remember the worst photo is the one not taken.