You might have noticed that most of the photos in this website appear with the camera EXIF data at the bottom of the post. Within that, you’ll often find the geocoordinates of the photo. Geotagging is important, because the sights and scenery will change over the next few years and it’ll be important to be able to go back to the same location and compare earlier photos with later ones.
I use a combination of hardware and software to geotag photos. In some cases (such as with Apple’s iPhone), geotagging photos occurs automatically. In other cases (such as when you use a camera without GPS capability), you need to also carry along a separate GPS device that will record your location as you take the photos. Then, a software program will take a gpx-format data file from your GPS device, and compare that to the time your photos were shot, then will write the geocoordinates into the camera EXIF data of the image for you.